Abstract
An electroplated part, which contains hardly any organic residues and has a uniform electroplated layer. An electroplating method for preparing the electroplated part is also provided. By controlling the ratio of the length of the motion trajectory of the electroplated part relative to an anode during the electroplating process to the width of the anode, and adding auxiliary cathodes to the electroplated part, the electroplating method improves the uniformity of the thickness of the electroplated layer at various positions of the electroplated part. A fixture for implementing the electroplating method and an electroplating apparatus are provided. The electroplated layer of the electroplated part prepared by the electroplating method has relatively uniform thickness and a high coverage rate, problems such as burn and fracture have hardly occurred during the electroplating process of the electroplated part, the yield of electroplated parts is high, and the scrap rate is low. In addition, the precision of the weight of plated layers of electroplated parts can reach 99% or above.
Claims
1. An electroplated part, comprising a substrate and an electroplated layer, the electroplated layer covering the substrate, wherein the content of organic residues in the electroplated layer is less than 0.2%.
2. The electroplated part according to claim 1, wherein the content of organic residues in the electroplated layer is less than 0.1%; the content of organic residues in the electroplated layer is less than 0.05%; the content of organic residues in the electroplated layer is less than 0.019%; wherein the ratio of the thickness of the electroplated layer at the thickest place to the thickness at the thinnest place on the substrate is (1-30]:1; the ratio of the thickness of the electroplated layer at the thickest place to the thickness at the thinnest place on the substrate is (1-20]:1; the ratio of the thickness of the electroplated layer at the thickest place to the thickness at the thinnest place on the substrate is (1-15]:1; the ratio of the thickness of the electroplated layer at the thickest place to the thickness at the thinnest place on the substrate is (1-12]:1.
3. (canceled)
4. The electroplated part according to claim 1, wherein the average thickness of the electroplated layer is 0.5-5 m; the thickness of the electroplated layer at the thickest place on the substrate is (1, 7.5] times the average thickness; the thickness of the electroplated layer at the thinnest place on the substrate is [0.25, 1) times the average thickness; wherein the thickness of the electroplated layer at the thinnest place on the substrate is 0.25-4.25 m; the thickness of the electroplated layer at the thinnest place on the substrate is 0.375-3.2 m; the thickness of the electroplated layer at the thinnest place on the substrate is 0.6-3.2 m; the thickness of the electroplated layer at the thinnest place on the substrate is 0.6-2.5 m: or wherein the thickness of the electroplated layer at the thickest place on the substrate is 1.1-15 m; the thickness of the electroplated layer at the thickest place on the substrate is 1.1-9.75 m; the thickness of the electroplated layer at the thickest place on the substrate is 1.1-7.5 m; the thickness of the electroplated layer at the thickest place on the substrate is 1.2-5 m.
5-6. (canceled)
7. The electroplated part according to claim 1, wherein the electroplated layer covers more than 99% of a surface of the substrate; the electroplated layer is a pure metal layer or an alloy layer; the content of zinc in the electroplated layer is not less than 50%; the content of zinc in the electroplated layer is more than 99%; wherein the mass-to-volume ratio of the electroplated part is 0.001-10 g/cm.sup.3; the mass-to-volume ratio of the electroplated part is 0.001-5 g/cm.sup.3; the mass-to-volume ratio of the electroplated part is 0.001-0.4 g/cm.sup.3; and an iron alloy comprises at least one of a low alloy steel or an iron-based alloy having a carbon content of no more than 2.5 wt. %.
8. The electroplated part according to claim 1, wherein a medical device comprises a vascular stent, a non-vascular endoluminal stent, an occluder, an orthopedic implant, a heart valve, a spacer, an artificial vessel, a dental implant device, a vascular clamp, a dental implant, a respiratory implant, a gynecological implant, an andrological implant, a suture, and a bolt; the substrate is made of a degradable metal or a degradable non-metal material; the substrate comprises at least one of pure iron, an iron alloy, pure zinc, a zinc alloy, pure magnesium, and a magnesium alloy.
9. (canceled)
10. A preparation method of the electroplated part according to claim 1, wherein the electroplated part is placed in an electroplating solution and moves relative to an anode at a certain amplitude and frequency with a fixture, wherein the length of a motion trajectory of the electroplated part relative to the anode during an electroplating process is 2-980 times the width of the anode; and/or auxiliary cathodes are connected to the electroplated part.
11. The preparation method according to claim 10, wherein the length of the motion trajectory of the electroplated part relative to the anode during the electroplating process is 2-540 times the width of the anode; the length of the motion trajectory of the electroplated part relative to the anode during the electroplating process is 2-400 times the width of the anode; the length of the motion trajectory of the electroplated part relative to the anode during the electroplating process is 2-240 times the width of the anode; the length of the motion trajectory of the electroplated part relative to the anode during the electroplating process is 2-150 times the width of the anode.
12. The preparation method according to claim 10, wherein the width of the anode is 0.1 cm; the amplitude of swing of the electroplated part relative to the anode is 0-180; the auxiliary cathodes are connected to two ends of the electroplated part in a longitudinal axis direction or in a direction parallel to an anode surface.
13. The preparation method according to claim 10, wherein the amplitude of swing of the electroplated part relative to the anode is 0-160; the frequency of motion of the electroplated part relative to the anode is 0.1 s-20 s/cycle; wherein the area of the auxiliary cathode is 30%-70% of the area of a cathode; the auxiliary cathode has a length of 0.5 mm-20 mm; the auxiliary cathode has a length of 0.5 mm-10 mm; the auxiliary cathode is of any shape; the auxiliary cathode comprises at least one of a linear type, an annular type, a ring type, a prismatic type, a pyramidal type, a spiral type, a wheel type, a cylindrical type, and a corrugated type.
14. (canceled)
15. The preparation method according to claim 10, wherein the cross-sectional area of the auxiliary cathode in a direction perpendicular to an anode surface or a longitudinal axis direction of the electroplated part is larger than the cross-sectional area of the short axis of the electroplated part; the auxiliary cathode is connected to the electroplated part through a linkage or a point.
16. The preparation method according to claim 15, wherein the linkage is one of a straight line or a non-straight line; the linkage is at least one of a linear type, an S type, a type, or a 0 type; the linkage is fixedly or detachably connected to the electroplated part, the fixture, and the auxiliary cathode.
17. The preparation method according to claim 10, wherein the electroplated part is subjected to a force of the fixture during the electroplating process; the magnitude of the force applied to the electroplated part by the fixture during the electroplating process is 110.sup.3 N-0.5 N; wherein the contact area between the electroplated part and the fixture is not more than 0.1 mm.sup.2; or wherein the temperature of the electroplating solution during the electroplating process of the electroplated part is 10 C.-50 C.; the current density during the electroplating process of the electroplated part is 1 A.Math.dm.sup.2-20 A.Math.dm.sup.2; the electroplating time during the electroplating process of the electroplated part is 10-300 s.
18-19. (canceled)
20. The preparation method according to claim 10, wherein each component in the electroplating solution is an inorganic substance.
21. The preparation method according to claim 10, wherein when zinc is contained in a plated layer, the electroplating solution comprises 3.4-4.5 wt. % of a zinc-containing component and 2.1-3.1 wt. % of a pH adjusting agent; or the electroplating solution comprises 1.5-3.0 wt. % of the zinc-containing component and 6.5-8.8 wt. % of the pH adjusting agent; the zinc-containing component is at least one of zinc chloride, zinc sulfate, and zinc oxide; the pH adjusting agent is at least one of boric acid, sodium borate, potassium borate, calcium borate, sodium hydroxide, and potassium hydroxide.
22. The preparation method according to claim 21, wherein the electroplating solution further comprises 15.5-19.5 wt. % of a chloride salt; the chloride salt is at least one of sodium chloride, potassium chloride, and ammonium chloride.
23. A fixture, configured to fix an electroplated part in an electroplating bath and drive the electroplated part to move relative to an anode.
24. The fixture according to claim 23, comprising a connecting portion and clamping portions perpendicularly connected to the connecting portion, wherein the clamping portion is parallel to a long axis direction of the electroplated part; an end of the connecting portion near the electroplated part has at least two connecting rods, and at least one clamping portion is connected to each connecting rod.
25. The fixture according to claim 24, wherein the distance between two connecting rods is [0.6, 0.98] times the distance between corresponding contact points of the electroplated part and the connecting rod; wherein the ratio of a distance between any two points connected by a straight line on a cross section of the clamping portion perpendicular to the length direction of the electroplated part to an inner diameter of the electroplated part is 1:1-1:20; the clamping portion has a length of 0.16 mm-7 mm.
26. (canceled)
27. The fixture according to claim 24, wherein more than 95% of a surface of the fixture is covered with an insulating layer; or more than 25% of the surface of the fixture is covered with the insulating layer; wherein a fixing part is further connected to an end of the connecting portion away from the electroplated part.
28. (canceled)
29. An electroplating apparatus, comprising the fixture according to claim 23, and further comprising a power supply, an electrolytic bath, and anodes, wherein the fixture is connected to the electroplating apparatus through a supporting rod.
30. The electroplating apparatus according to claim 29, wherein the number of the anodes is greater than or equal to 2; the center position of the two or more anodes coincides with the center position of a motion trajectory of an electroplated part; wherein the width of the anode is 0.1 cm; the electroplating apparatus further comprises a component configured to control and drive relative motion of the fixture and the anode; and further comprising a display screen.
31-32. (canceled)
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0097] Various other advantages and benefits will become apparent to a person skilled in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for the purpose of illustrating the preferred embodiments and are not to be construed as limiting the present invention. Moreover, throughout the accompanying drawings, the same components are indicated by the same reference numerals.
[0098] FIG. 1 is an exemplary view of an electroplating apparatus adopted in examples and comparative examples of the present invention, where:1positive electrode, 2negative electrode, 3direct current power supply, 4anode, 5electroplating bath, 6fixture (cathode), 7electroplated part, and 8transmission mechanism; and
[0099] FIGS. 2-8 are exemplary views of fixtures adopted in examples and comparative examples of the present invention, where:1fixing part, 2connecting portion, 3clamping portion, Ddistance between connecting rods, i.e., width of the connecting portion, and 9auxiliary cathode.
DETAILED DESCRIPTION OF THE INVENTION
[0100] The following descriptions are only preferred embodiments of the present invention, and the protection of the present invention is not limited to the following preferred embodiments. For example, in the examples, the description is given by taking a stent or a stent of a certain model as an example, but it does not mean that the technical solution of the present invention is only suitable for the stent or the stent of a certain model. It should be noted that several variations and improvements made by a person skilled in the art based on the present inventive concept fall within the scope of the present invention. The reagents or instruments used are conventional products that are commercially available through regular channels without specifying the manufacturer.
Test Methods
1. Determination of Thickness of Electroplated Layer
[0101] In the present invention, the thickness of the electroplated layer is determined using an X-ray fluorescence plating thickness gauge method. First, the apparatus is calibrated using a standard block of a corresponding element. After the calibration is completed, a stent sample for testing the thickness of the electroplated layer is fixed on a sample stage and put into the X-ray fluorescence plating thickness gauge. The types of coating and substrate metal are set, the measurement time is set as 10-15 s, and the thickness is in m. OK is clicked to test the thicknesses of the plated layer at various positions on the electroplated part, and the thicknesses at the thickest place and the thinnest place are determined.
2. Determination of Organic Residues in Plated Layer
[0102] According to the method recorded in the national standard GB/T 2013-2006/ISO 15350:2000 Steel and iron-Determination of total carbon and sulfur content-Infrared absorption method after combustion in an induction furnace, the carbon contents C.sub.1 and C.sub.2 in the electroplated part substrate and the electroplated part are detected, respectively, and the carbon content C=C.sub.1C.sub.2 in the electroplated layer is determined.
[0103] According to the statistics on the percentage contents of carbon atoms in various types of organic substances, formic acid has the lowest carbon content of 26.1%. Benzene and acetylene have the highest carbon content of 92.3%. Therefore, it can be considered that the carbon content in organic substances is generally between 26.1%-92.3%, and therefore the content of organic residues is 1.083-3.831 times the carbon content. Therefore, in the present application, the percentage of organic residues in the present application is obtained by multiplying the carbon content measured according to the above-mentioned national standard by 3.831.
[0104] It should be noted that, in the present invention, the carbon content in the electroplated part is determined using the method recorded in the national standard GB/T 2013-2006/ISO 15350:2000 Steel and iron-Determination of total carbon and sulfur content-Infrared absorption method after combustion in an induction furnace, and in the second paragraph of 1 Scope of this standard, it is clearly stated that the method is applicable to the determination of carbon content with a mass fraction of 0.005%-4.3%. Therefore, the organic residues in the electroplated layer have a low mass fraction ranging from 0.019% to 16.47%. Therefore, in the present invention, when the carbon content in a test object cannot be measured using the method, it can be considered that the carbon content in the test object is less than 0.005%, and further it can be considered that the mass percentage content of the organic residues in the test object is less than 0.019%, and even less than 0.0125% (based on the calculation from the carbon content in glucose).
Example 1
[0105] As shown in FIG. 1, the anode width was 20 mm, a trajectory of one cycle of stent motion was 50 mm, the motion period was 1 s, and the swing angle was 60. In a zinc plating solution containing 50 g/L zinc chloride, 25 g/L boric acid, and 200 g/L potassium chloride, a 30018 stent was used for electroplating. The solution temperature was 10 C., the stent area was 0.009 dm.sup.2, the mass-lumen volume ratio was 0.012 g/cm.sup.3, and the stent length was 18 mm. As shown in FIG. 2, the fixture width D was 16 mm, the ratio of the fixture width to an electroplated part length was 0.89, the contact area between the fixture and the stent was 0.1 mm.sup.2, and the clamping force was 0.005 N. With a current of 0.09 A, a current density of 10 A/dm.sup.2, and an electroplating time of 19 s, a zinc layer with an average thickness of 1 m was obtained. The maximum thickness at a head end of an outer wall of the stent was 3.5 m, the minimum thickness at a middle part of an inner wall was 0.75 m, and the ratio of the maximum thickness to the minimum thickness was 4.67. Five stents were electroplated consecutively, and the RSD of the mass of the electroplated layer was 0.35%. There was no burn or fracture of the stents. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%. Two stents were implanted into the abdominal aorta of rabbits. A first stent was removed after 3 months. The stent structure was complete, and the measured radial support strength was 74 kPa, which met the mechanical performance requirements for the early 3 months of implantation. A second stent was removed after 6 months with no cell proliferation and no stent rod fracture.
Example 2
[0106] As shown in FIG. 1, the anode width was 20 mm, the trajectory of one cycle of stent motion was 80 mm, the motion period was 2 s, and the swing angle was 90. In a zinc plating solution containing 50 g/L zinc chloride, 25 g/L boric acid, and 200 g/L potassium chloride, a 30018 stent was used for electroplating. The solution temperature was 20 C., the stent area was 0.009 dm.sup.2, the mass-lumen volume ratio was 0.012 g/cm.sup.3, and the stent length was 18 mm. As shown in FIG. 2, the fixture width D was 16 mm, the ratio of the fixture width to an electroplated part length was 0.89, the contact area between the fixture and the stent was 0.1 mm.sup.2, and the clamping force was 0.005 N. With a current of 0.09 A, a current density of 10 A/dm.sup.2, and an electroplating time of 19 s, a zinc layer with an average thickness of 1 m was obtained. The maximum thickness at a head end of an outer wall of the stent was 3.0 m, the minimum thickness at a middle part of an inner wall was 0.76 m, and the ratio of the maximum thickness to the minimum thickness was 3.94. Five stents were electroplated consecutively, and the RSD of the mass of the electroplated layer was 0.34%. There was no burn or fracture of the stents. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%. Two stents were implanted into the abdominal aorta of rabbits. A first stent was removed after 3 months. The stent structure was complete, and the measured radial support strength was 76 kPa, which met the mechanical performance requirements for the early 3 months of implantation. A second stent was removed after 6 months with no cell proliferation and no stent rod fracture.
Example 3
[0107] As shown in FIG. 1, the anode width was 20 mm, the trajectory of one cycle of stent motion was 120 mm, the motion period was 3 s, and the swing angle was 120. In a zinc plating solution containing 15 g/L zinc oxide and 120 g/L sodium hydroxide, a 30018 stent was used for electroplating. The solution temperature was 30 C., the stent area was 0.009 dm.sup.2, the mass-lumen volume ratio was 0.012 g/cm.sup.3, and the stent length was 18 mm. As shown in FIG. 5, the fixture width D was 16 mm, the ratio of the fixture width to an electroplated part length was 0.89, the contact area between the fixture and the stent was 0.1 mm.sup.2, and the clamping force was 0.005 N. With a current of 0.09 A, a current density of 10 A/dm.sup.2, and an electroplating time of 19 s, a zinc layer with an average thickness of 1 m was obtained. The maximum thickness at a head end of an outer wall of the stent was 2.8 m, the minimum thickness at a middle part of an inner wall was 0.77 m, and the ratio of the maximum thickness to the minimum thickness was 3.63. Five stents were electroplated consecutively, and the RSD of the mass of the electroplated layer was 0.33%. There was no burn or fracture of the stents. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%. Two stents were implanted into the abdominal aorta of rabbits. A first stent was removed after 3 months. The stent structure was complete, and the measured radial support strength was 78 kPa, which met the mechanical performance requirements for the early 3 months of implantation. A second stent was removed after 6 months with no cell proliferation and no stent rod fracture.
Example 4
[0108] As shown in FIG. 1, the anode width was 20 mm, the trajectory of one cycle of stent motion was 160 mm, the motion period was 4 s, and the swing angle was 135. In a zinc plating solution containing 15 g/L zinc oxide and 120 g/L sodium hydroxide, a 30018 stent was used for electroplating. The solution temperature was 40 C., a stent area was 0.009 dm.sup.2, the mass-lumen volume ratio was 0.012 g/cm.sup.3, and the stent length was 18 mm. As shown in FIG. 4, the fixture width D was 16 mm, the ratio of the fixture width to an electroplated part length was 0.89, the contact area between the fixture and the stent was 0.1 mm.sup.2, and the clamping force was 0.005 N. With a current of 0.09 A, a current density of 10 A/dm.sup.2, and an electroplating time of 19 s, a zinc layer with an average thickness of 1 m was obtained. The maximum thickness at a head end of an outer wall of the stent was 2.6 m, the minimum thickness at a middle part of an inner wall was 0.78 m, and the ratio of the maximum thickness to the minimum thickness was 3.33. Five stents were electroplated consecutively, and the RSD of the mass of the electroplated layer was 0.32%. There was no burn or fracture of the stents. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%. Two stents were implanted into the abdominal aorta of rabbits. A first stent was removed after 3 months. The stent structure was complete, and the measured radial support strength was 81 kPa, which met the mechanical performance requirements for the early 3 months of implantation. A second stent was removed after 6 months with no cell proliferation and no stent rod fracture.
Example 5
[0109] As shown in FIG. 1, the anode width was 20 mm, the trajectory of one cycle of stent motion was 800 mm, the motion period was 5 s, and the swing angle was 150. In a zinc plating solution containing 50 g/L zinc chloride, 25 g/L boric acid, and 200 g/L potassium chloride, an 80023 stent was used for electroplating. The solution temperature was 50 C., the stent area was 0.025 dm.sup.2, a mass-lumen volume ratio was 0.033 g/cm.sup.3, and the stent length was 23 mm. As shown in FIG. 2, the fixture width D was 18.5 mm, the ratio of the fixture width to an electroplated part length was 0.8, the contact area between the fixture and the stent was 0.1 mm.sup.2, and the clamping force was 0.05 N. With a current of 0.25 A, a current density of 10 A/dm.sup.2, and an electroplating time of 19 s, a zinc layer with an average thickness of 1 m was obtained. The maximum thickness at a head end of an outer wall of the stent was 2.2 m, the minimum thickness at a middle part of an inner wall was 0.79 m, and the ratio of the maximum thickness to the minimum thickness was 3.09. Five stents were electroplated consecutively, and the RSD of the weight of the electroplated layer was 0.31%. There was no burn or fracture of the stents. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%. Two stents were implanted into the abdominal aorta of rabbits. A first stent was removed after 3 months. The stent structure was complete, and the measured radial support strength was 83 kPa, which met the mechanical performance requirements for the early 3 months of implantation. A second stent was removed after 6 months with no cell proliferation and no stent rod fracture.
Example 6
[0110] As shown in FIG. 1, the anode width was 200 mm, the trajectory of one cycle of stent motion was 200 mm, the motion period was 1 s, and the swing angle was 60. In a zinc plating solution containing 50 g/L zinc chloride, 25 g/L boric acid, and 200 g/L potassium chloride, a 30018 stent was used for electroplating. The solution temperature was 25 C., the stent area was 0.009 dm.sup.2, the mass-lumen volume ratio was 0.012 g/cm.sup.3, and the stent length was 18 mm. As shown in FIG. 3, the fixture width D was 16 mm, the ratio of the fixture width to an electroplated part length was 0.89, the contact area between the fixture and the stent was 0.1 mm.sup.2, and the clamping force was 0.005 N. With a current of 0.06 A, a current density of 5 A/dm.sup.2, and an electroplating time of 19 s, a zinc layer with an average thickness of 0.5 m was obtained. The maximum thickness at a head end of an outer wall of the stent was 2.5 m, the minimum thickness at a middle part of an inner wall was 0.375 m, and the ratio of the maximum thickness to the minimum thickness was 4.67. Five stents were electroplated consecutively, and the RSD of the mass of the electroplated layer was 0.25%. There was no burn or fracture of the stents. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%. Two stents were implanted into the abdominal aorta of rabbits. A first stent was removed after 3 months. The stent structure was complete, and the measured radial support strength was 50 kPa, which met the mechanical performance requirements for the early 3 months of implantation. A second stent was removed after 6 months with no cell proliferation and partial stent rod fracture.
Example 7
[0111] As shown in FIG. 1, the anode width was 200 mm, the trajectory of one cycle of stent motion was 400 mm, the motion period was 1 s, and the swing angle was 60. In a zinc plating solution containing 50 g/L zinc chloride, 25 g/L boric acid, and 200 g/L potassium chloride, a 30018 stent was used for electroplating. The solution temperature was 25 C., a stent area was 0.009 dm.sup.2, the mass-lumen volume ratio was 0.012 g/cm.sup.3, and the stent length was 18 mm. As shown in FIG. 7, the fixture width D was 16 mm, the ratio of the fixture width to an electroplated part length was 0.89, the contact area between the fixture and the stent was 0.1 mm.sup.2, and the clamping force was 0.005 N. With a current of 0.15 A, a current density of 10 A/dm.sup.2, and an electroplating time of 57 s, a zinc layer with an average thickness of 3 m was obtained. The maximum thickness at a head end of an outer wall of the stent was 9.75 m, the minimum thickness at a middle part of an inner wall was 2.34 m, and the ratio of the maximum thickness to the minimum thickness was 4.17. Five stents were electroplated consecutively, and the RSD of the mass of the electroplated layer was 0.30%. There was no burn or fracture of the stents. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%. Two stents were implanted into the abdominal aorta of rabbits. A first stent was removed after 3 months. The stent structure was complete, and the measured radial support strength was 90 kPa, which met the mechanical performance requirements for the early 3 months of implantation. A second stent was removed after 6 months with slight cell proliferation, a vascular stenosis rate reaching 27%, and no stent rod fracture.
Example 8
[0112] As shown in FIG. 1, the anode width was 200 mm, the trajectory of one cycle of stent motion was 400 mm, the motion period was 1 s, and the swing angle was 60. In a zinc plating solution containing 50 g/L zinc chloride, 25 g/L boric acid, and 200 g/L potassium chloride, a 30018 stent was used for electroplating. The solution temperature was 25 C., the stent area was 0.009 dm.sup.2, the mass-lumen volume ratio was 0.012 g/cm.sup.3, and the stent length was 18 mm. As shown in FIG. 8, the fixture width D was 16 mm, the ratio of the fixture width to an electroplated part length was 0.89, the contact area between the fixture and the stent was 0.1 mm.sup.2, and the clamping force was 0.005 N. With a current of 0.27 A, a current density of 15 A/dm.sup.2, and an electroplating time of 50.7 s, a zinc layer with an average thickness of 4 m was obtained. The maximum thickness at a head end of an outer wall of the stent was 12.8 m, the minimum thickness at a middle part of an inner wall was 3.2 m, and the ratio of the maximum thickness to the minimum thickness was 4. Five stents were electroplated consecutively, and the RSD of the mass of the electroplated layer was 0.35%. There was no burn or fracture of the stents. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%. Two stents were implanted into the abdominal aorta of rabbits. A first stent was removed after 3 months. The stent structure was complete, and the measured radial support strength was 94 kPa, which met the mechanical performance requirements for the early 3 months of implantation. A second stent was removed after 6 months with slight cell proliferation in some sites, a vascular stenosis rate reaching 30%, and no stent rod fracture.
Example 9
[0113] As shown in FIG. 1, the anode width was 20 mm, the trajectory of one cycle of stent motion was 400 mm, the motion period was 1 s, and the swing angle was 60. In a zinc plating solution containing 50 g/L zinc chloride, 25 g/L boric acid, and 200 g/L potassium chloride, a 30018 stent was used for electroplating. The solution temperature was 25 C., the stent area was 0.009 dm.sup.2, the mass-lumen volume ratio was 0.012 g/cm.sup.3, and the stent length was 18 mm. As shown in FIG. 6, the fixture width D was 16 mm, the ratio of the fixture width to an electroplated part length was 0.89, the contact area between the fixture and the stent was 0.1 mm.sup.2, and the clamping force was 0.010 N. With a current of 0.36 A, a current density of 20 A/dm.sup.2, and an electroplating time of 47.5 s, a zinc layer with an average thickness of 5 m was obtained. The maximum thickness at a head end of an outer wall of the stent was 15 m, the minimum thickness at a middle part of an inner wall was 4.25 m, and the ratio of the maximum thickness to the minimum thickness was 3.53. Five stents were electroplated consecutively, and the RSD of the mass of the electroplated layer was 0.35%. There was no burn or fracture of the stents. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%. Two stents were implanted into the abdominal aorta of rabbits. A first stent was removed after 3 months. The stent structure was complete, and the measured radial support strength was 98 kPa, which met the mechanical performance requirements for the early 3 months of implantation. A second stent was removed after 6 months with certain cell proliferation in some sites, a vascular stenosis rate reaching 35%, and no stent rod fracture.
Example 10
[0114] As shown in FIG. 1, the anode width was 200 mm, the trajectory of one cycle of stent motion was 400 mm, the motion period was 1 s, and the swing angle was 60. In a zinc plating solution containing 50 g/L zinc chloride, 25 g/L boric acid, and 200 g/L potassium chloride, two sections of electroplating were added at two ends of a 30018 stent. The solution temperature was 25 C., the stent area was 0.012 dm.sup.2, the mass-lumen volume ratio was 0.012 g/cm.sup.3, and the stent length was 22 mm. As shown in FIG. 2, the fixture width D was 20 mm, the ratio of the fixture width to an electroplated part length was 0.91, the contact area between the fixture and the stent was 0.1 mm.sup.2, and the clamping force was 0.005 N. With a current of 0.06 A, a current density of 5 A/dm.sup.2, and an electroplating time of 38 s, a zinc layer with an average thickness of 1 m was obtained. Each of two sections at the ends of the stent was removed by 2 mm. The maximum thickness at a head end of an outer wall of the stent was 2.48 m, the minimum thickness at a middle part of an inner wall was 0.6 m, and the ratio of the maximum thickness to the minimum thickness was 4.13. Five stents were electroplated consecutively, and the RSD of the mass of the electroplated layer was 0.35%. There was no burn or fracture of the stents. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%. Two stents were implanted into the abdominal aorta of rabbits. A first stent was removed after 3 months. The stent structure was complete, and the measured radial support strength was 76 kPa, which met the mechanical performance requirements for the early 3 months of implantation. A second stent was removed after 6 months with no cell proliferation and no stent rod fracture.
Example 11
[0115] As shown in FIG. 1, the anode width was 200 mm, the trajectory of one cycle of magnesium bone nail motion was 400 mm, the motion period was 1 s, and the swing angle was 60. In an electroplating solution containing 90 g/L zinc chloride, 10 g/L ferrous sulfate, and 200 g/L potassium chloride, the magnesium bone nail was electroplated. The solution temperature was 25 C., the bone nail surface area was 0.009 dm.sup.2, and the bone nail length was 18 mm. As shown in FIG. 3, the fixture width D was 16 mm, the ratio of the fixture width to the bone nail length was 0.89, the contact area between the fixture and the bone nail was 0.1 mm.sup.2, and the clamping force was 0.28 N. With a current of 0.018 A, a current density of 2 A/dm.sup.2, and an electroplating time of 95 s, a zinc-iron alloy layer with an average thickness of 1 m was obtained, which contained 99.5% zinc and 0.5% iron. The maximum thickness at a head end of the bone nail was 2.4 m, the minimum thickness at a middle part was 0.8 m, and the ratio of the maximum thickness to the minimum thickness was 3.0. Five bone nails were electroplated consecutively, and the RSD of the mass of the electroplated layer was 0.25%. There was no burn or fracture of the bone nails. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%. Two bone nails were implanted into the ankle joint of rabbits. A first bone nail was removed after 3 months, and the bone nail structure was complete. A second bone nail was removed after 6 months with no cell proliferation, and the bone nail substrate was basically free from corrosion.
Example 12
[0116] As shown in FIG. 1, the anode width was 200 mm, the trajectory of one cycle of iron-manganese occluder motion was 100 mm, the motion period was 1 s, and the swing angle was 60. Electroplating was performed in a zinc plating solution containing 50 g/L zinc chloride, 25 g/L boric acid, and 200 g/L potassium chloride. The solution temperature was 25 C., the occluder had a surface area of 0.09 dm.sup.2 and the diameter of 18 mm. As shown in FIG. 2, the fixture width D was 16 mm, the ratio of the fixture width to the occluder diameter was 0.89, a contact area between the fixture and the occluder was 0.1 mm.sup.2, and the clamping force was 0.35 N. With a current of 0.72 A, a current density of 8 A/dm.sup.2, and an electroplating time of 23.8 s, a zinc layer with an average thickness of 1 m was obtained. The maximum thickness of a circumference of the occluder was 7.5 m, the minimum thickness of a central interior was 0.25 m, and a ratio of the maximum thickness to the minimum thickness was 30. Five occluders were electroplated consecutively, and the RSD of the mass of the electroplated layer was 0.25%. There was no burn or fracture of the occluders. Two occluders were implanted into the interatrial septum of rabbits. A first occluder was removed after 1 month with no endothelialization in the middle position and removed after 2 months with no endothelialization in the middle position and complete endothelialization at the end portion of an outer wall. A second occluder was removed after 6 months, and cell proliferation at the end portion was severe.
Example 13
[0117] As shown in FIG. 1, the anode width was 120 mm, the trajectory of one cycle of stent motion was 120 mm, the motion period was 3 s, and the swing angle was 120. In a zinc plating solution containing 15 g/L zinc oxide and 120 g/L sodium hydroxide, a 30018 stent was used for electroplating. The solution temperature was 30 C., the stent area was 0.009 dm.sup.2, the mass-lumen volume ratio was 0.012 g/cm.sup.3, and the stent length was 18 mm. As shown in FIG. 2, the fixture width D was 16 mm, the ratio of the fixture width to an electroplated part length was 0.89, the contact area between the fixture and the stent was 0.1 mm.sup.2, and the clamping force was 0.005 N. With a current of 0.09 A, a current density of 10 A/dm.sup.2, and an electroplating time of 19 s, a zinc layer with an average thickness of 1 m was obtained. The maximum thickness at a head end of an outer wall of the stent was 5.0 m, the minimum thickness at a middle part of an inner wall was 0.6 m, and the ratio of the maximum thickness to the minimum thickness was 8.33. Five stents were electroplated consecutively, and the RSD of the mass of the electroplated layer was 0.3%. There was no burn or fracture of the stents. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%. Two stents were implanted into the abdominal aorta of rabbits. A first stent was removed after 3 months. The stent structure was complete, and the measured radial support strength was 65 kPa, which met the mechanical performance requirements for the early 3 months of implantation. A second stent was removed after 6 months with no cell proliferation and no stent rod fracture.
Comparative Example 1
[0118] As shown in FIG. 1, the anode width was 20 mm, the trajectory of one cycle of stent motion was 50 mm, the motion period was 1 s, and the swing angle was 60. In a zinc plating solution containing 50 g/L zinc chloride, 25 g/L boric acid, and 200 g/L potassium chloride, a 30018 stent was used for electroplating. The solution temperature was 10 C., the stent area was 0.009 dm.sup.2, the mass-lumen volume ratio was 0.012 g/cm.sup.3, and the stent length was 18 mm. As shown in FIG. 2, the fixture width D was 17.5 mm, the ratio of the fixture width to an electroplated part length was 0.97, the contact area between the fixture and the stent was 0.1 mm.sup.2, and the clamping force was 0.0005 N. With a current of 0.09 A, a current density of 10 A/dm.sup.2, and an electroplating time of 19 s, a zinc layer with an average thickness of 1 m was obtained. The maximum thickness at a head end of an outer wall of the stent was 3.6 m, the minimum thickness at a middle part of an inner wall was 0.76 m, and the ratio of the maximum thickness to the minimum thickness was 4.73. Two ends of the stent were ablated and fused with the fixture, resulting in disqualification. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%.
Comparative Example 2
[0119] As shown in FIG. 1, the anode width was 20 mm, the trajectory of one cycle of stent motion was 80 mm, the motion period was 2 s, and the swing angle was 90. In a zinc plating solution containing 50 g/L zinc chloride, 25 g/L boric acid, and 200 g/L potassium chloride, a 30018 stent was used for electroplating. The solution temperature was 20 C., the stent area was 0.009 dm.sup.2, the mass-lumen volume ratio was 0.012 g/cm.sup.3, and the stent length was 18 mm. As shown in FIG. 2, the fixture width D was 12 mm, the ratio of the fixture width to an electroplated part length was 0.67, the contact area between the fixture and the stent was 0.1 mm.sup.2, and the clamping force was 0.8 N. With a current of 0.09 A, a current density of 10 A/dm.sup.2, and an electroplating time of 19 s, a zinc layer with an average thickness of 1 m was obtained. The stent was disqualified due to overall distortion and deformation. Five stents were electroplated consecutively, and the RSD of the mass of the electroplated layer was 0.4%. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%.
Comparative Example 3
[0120] As shown in FIG. 1, the anode width was 200 mm, the trajectory of one cycle of stent motion was 200 mm, the motion period was 1 s, and the swing angle was 60. In a zinc plating solution containing 50 g/L zinc chloride, 25 g/L boric acid, 200 g/L potassium chloride, 0.1 g/L benzylideneacetone, 0.6 g/L fatty alcohol polyoxyethylene ether O-20, and 0.2 g/L sodium benzenesulfonate, a 30018 stent was used for electroplating. The solution temperature was 25 C., a stent area was 0.009 dm.sup.2, the mass-lumen volume ratio was 0.012 g/cm.sup.3, and the stent length was 18 mm. As shown in FIG. 2, the fixture width D was 16 mm, the ratio of the fixture width to an electroplated part length was 0.89, the contact area between the fixture and the stent was 0.1 mm.sup.2, and the clamping force was 0.005 N. With a current of 0.09 A, a current density of 10 A/dm.sup.2, and an electroplating time of 19 s, a zinc layer with an average thickness of 1 m was obtained. The maximum thickness at a head end of an outer wall of the stent was 2.4 m, the minimum thickness at a middle part of an inner wall was 0.8 m, and a ratio of the maximum thickness to the minimum thickness was 3. Five stents were electroplated consecutively, the RSD of the mass of the electroplated layer was 0.25%, and there was no burn or fracture of the stents. The mass percentage content of the organic residues in the electroplated layer was 0.8%. Two weeks after stent implantation in the abdominal aorta of rabbits, the stent was removed, and the vessels showed massive inflammation and pustules.
Comparative Example 4
[0121] As shown in FIG. 1, the anode width was 600 mm, the trajectory of one cycle of stent motion was 50 mm, the motion period was 4 s, and the swing angle was 35. In a zinc plating solution containing 15 g/L zinc oxide and 120 g/L sodium hydroxide, a 30018 stent was used for electroplating. The solution temperature was 40 C., the total stent area was 0.009 dm.sup.2, the mass-lumen volume ratio was 0.012 g/cm.sup.3, and the stent length was 18 mm. A single fixture width D was 16 mm, the ratio of the fixture width to an electroplated part length was 0.87, the contact area between the fixture and the stent was 1 mm.sup.2, and the single clamping force was 0.005 N. With a current of 0.09 A, a current density of 10 A/dm.sup.2, and an electroplating time of 95 s, a zinc layer with an average thickness of 5 m was obtained. The maximum thickness at a head end of an outer wall of the stent was 18 m, the minimum thickness at a middle part of an inner wall was 0.34 m, and the ratio of the maximum thickness to the minimum thickness was 52.9. Five stents were electroplated consecutively, and the RSD of the mass of the electroplated layer was 0.5%. There was no burn or fracture of the stents. The carbon content was not detected, and the content of organic residues in the electroplated layer was lower than a detection limit. Therefore, the mass percentage content of the organic residues in the electroplated layer was less than 0.019%. Two stents were implanted into the abdominal aorta of rabbits. A first stent was removed after 3 months, and the stent structure was complete. A second stent was removed after 6 months with obvious cell proliferation in most sites, a vascular restenosis rate reaching 70%, and partial stent rod fracture.
[0122] Numerous other examples of the present invention are possible. Without departing from the spirit of the present invention and the essence thereof, a person skilled in the art may make various corresponding changes and deformations in accordance with the present invention, and these corresponding changes and deformations shall fall within the scope of the claims appended to the present invention.
