METHOD FOR SURFACE TREATMENT AND/OR PRODUCTION OF A MEDICAL PRODUCT, AND A MEDICAL PRODUCT

Abstract

A medical product and a method of surface treatment and/or manufacture of the medical product. The method includes the step of electrochemically etching the medical product. The medical product can include a metal or alloy and have one or more of the following features: a pitting corrosion potential of 100 mV to 1200 mV, a contact angle of 90° to 140°, and a passive layer having a thickness of 1 nm to 10 nm that coats at least sections of the surface of the medical product.

Claims

1.-14. (canceled)

15. A method of surface treating and/or producing a precursor or a component of a surgical instrument, the precursor or the component of the surgical instrument comprising a metal or an alloy, the method comprising the step of electrochemically etching the precursor or the component of the surgical instrument at a voltage applied to an anode of 1.4 V to 1.7 V and/or at a current density of 1.6 A/dm.sup.2 to 2.2 A/dm.sup.2.

16. The method according to claim 15, wherein the step of electrochemically etching the precursor or the component of the surgical instrument is preceded by a grinding operation on a surface of the precursor or the component of the surgical instrument.

17. The method according to claim 15, wherein the surface of the precursor or the component of the surgical instrument is not treated with a blasting agent and/or is not electropolished.

18. The method according to claim 15, wherein the step of electrochemically etching the precursor or the component of the surgical instrument is conducted more than once.

19. The method according to claim 15, wherein the step of electrochemically etching the precursor or the component of the surgical instrument is performed using an acidic aqueous electrolyte solution.

20. The method according to claim 19, wherein the acidic aqueous electrolyte solution comprises a mineral acid or a mineral acid mixture.

21. The method according to claim 19, wherein the acidic aqueous electrolyte solution comprises a mineral acid selected from the group consisting of phosphoric acid, sulfuric acid and a mixture thereof.

22. The method according to claim 16, wherein the step of electrochemically etching the precursor or the component of the surgical instrument is conducted over a period of 6 min to 14 min.

23. The method according to claim 16, wherein the voltage applied to the anode is between 1.45 V and 1.65 V during the step of electrochemically etching the precursor or the component of the surgical instrument.

24. The method according to claim 16, wherein the current density is between 1.8 A/dm.sup.2 and 2.0 A/dm.sup.2 during the step of electrochemically etching the precursor or the component of the surgical instrument.

25. The method according to claim 16, wherein the step of electrochemically etching the precursor or the component of the surgical instrument is conducted at a temperature of 20° C. to 90° C.

26. The method according to claim 16, wherein a surface of the precursor or the component of the surgical instrument is not treated with a passivating acid or a passivating acid-containing solution.

27. The method according to claim 16, wherein the step of electrochemically etching the precursor or the component of the surgical instrument is followed by the steps of: packing the precursor or the component of the surgical instrument; and sterilizing the precursor or the component of the surgical instrument.

28. The method according to claim 27, wherein the step of sterilizing the precursor or the component of the surgical instrument is performed prior to the step of packing the precursor or the component of the surgical instrument.

29. The method according to claim 16, wherein the precursor or the component of the surgical instrument comprises a stainless steel.

30. The method according to claim 29, wherein the stainless steel is a chromium-containing stainless steel.

31. The method according to claim 30, wherein the chromium-containing stainless steel is a chromium-containing, corrosion-resistant stainless steel.

32. The method according to claim 29, wherein the stainless steel is a martensitic, corrosion-resistant stainless steel.

33. The method according to claim 16, wherein the step of electrochemically etching the precursor or the component of the surgical instrument is preceded by the step of: slide finishing on the surface of the precursor or the component of the surgical instrument; and/or belt finishing on the surface of the precursor or the component of the surgical instrument.

34. A precursor or a component of a surgical instrument produced by the method of claim 16, the precursor or the component of the surgical instrument comprising a passive layer having a thickness of 1 nm to 10 nm that coats at least sections of a surface of the precursor or the component of the surgical instrument.

Description

DETAILED DESCRIPTION

[0184] Further features and advantages of the invention will be apparent from the description of preferred embodiments with reference to examples that follows. It is possible here for features of the invention each to be implemented on their own or in combination with one another. The embodiments described hereinafter serve to further elucidate the invention without restriction thereto.

EXAMPLES

1. Surface Treatment of a Surgical Instrument or Representative Specimen by a Method of the Invention

[0185] The specimens used, and also surgical instruments, were produced from identical martensitic nonrusting steel (X20Cr13) and by identical manufacturing steps and parameters.

[0186] SEM/EDX analyses (extraneous material and doubled-over material) were conducted on the instruments and sample platelets.

[0187] Potentiodynamic tests (pitting corrosion potential) were likewise conducted on the instruments and sample platelets.

[0188] Contact angle measurements (contact angle) were conducted on sample platelets (planar surface without shadows).

[0189] Gloss measurement (gloss) was conducted on sample platelets (planar surface without shadows).

[0190] 3D laser confocal microscopy (roughness depth) was conducted on sample platelets (planar surface without shadows).

[0191] Prior to the surface treatment, surgical instruments, corrosion specimens and sample platelets according to the current production chain of surgical instruments were shaped and heat-treated.

[0192] For subsequent surface treatment, a surgical instrument (BH110R clamp), a corrosion specimen and sample platelets were treated by means of slide finishing in acidic solution over a period of four hours and then brightened by slide finishing in aqueous solution over a period of one hour.

[0193] Thereafter, the surgical instruments, corrosion specimens and sample platelets were electrochemically etched. For this purpose, the parts were immersed into an acidic aqueous electrolyte solution having a mineral acid content of 11% by weight of phosphoric acid and 61% by weight of sulfuric acid that was at a temperature of 40° C., and a DC voltage was applied for 10 minutes, so as to result in a voltage of 1.5 V at the anode. A current density of 2.0 A/dm.sup.2 was established here.

[0194] Finally, the surgical instruments, corrosion specimens and sample platelets were passivated. For this purpose, the parts were immersed into a 10% by weight citric acid solution at a temperature of 60° C. for 10 minutes. Thereafter, the parts were pickled and cleaned in ethanol.

[0195] After the production, the formation of the surface of instruments and sample platelets was examined via scanning electron microscopy with an energy-dispersive x-ray spectroscopy unit. The SEM studies showed etching trenches distributed virtually randomly over the surface with slight localization at the grain boundaries. These were in the order of magnitude range of about 5 μm. The chemical composition was homogeneous and had a lower chromium level compared to the starting material at about 0.1% by weight. This was because of the chromium carbides leached out of the surface.

[0196] In addition, the topography of the surface on the instruments and sample platelets was assessed by means of 3D laser confocal microscopy and by metallographic sections. By means of the 3D laser confocal measurements, it was possible to determine an average roughness depth of 0.5 μm. This was attributable to the depth of the etching trenches which, according to the metallographic studies, were in the range of 1-3 μm.

[0197] The change in the reflection characteristics was examined by a gloss measurement on the test platelets. A distinct reduction in gloss was found with values of 3.7 gloss units (20°) and 21.6 gloss units (60°). The reflection characteristics could thus be determined as being strongly matt.

[0198] Analysis of the wetting by liquids was accomplished by contact angle measurement on the test platelets. An average contact angle of 116.3° was determined here.

[0199] Finally, the electrochemical/corrosive characteristics of the surface formed were examined by potentiodynamic polarization measurements on corrosion specimens, and pitting corrosion potential was ascertained. For comparison as to whether the measurements that were measured on test specimens relate to the instrument, pitting corrosion potential was measured on a laboratory instrument. The results for the test specimens were confirmed here. It was possible here to record a pitting corrosion potential of 475 mV.

2. Surface Treatment of a Surgical Instrument by a Method of the Generic Type

[0200] A surgical instrument (BH110R clamp), corrosion specimens and sample platelets were first treated by means of slide finishing over a period of four hours. Thereafter, the surgical instrument and the specimens were brightened over a period of one hour.

[0201] Thereafter, the surgical instrument and the specimens were treated by means of blasting. For this purpose, glass beads having an average diameter of 40 μm to 70 μm were used. The blasting was conducted in an injector blasting system under a pressure of 4 bar.

[0202] Subsequently, the surgical instrument and the specimens were subjected to passivation. For this purpose, a 10% citric acid solution was used. The passivating was effected at a temperature of 55° C. over a period of 10 minutes.

[0203] On conclusion of the surface treatment of the surgical instrument and of the specimens, many instances of doubled-over material or overlapping material were detectable. In addition, an extraneous material transfer of 1.4% was detected. The roughness depth was in the region of 0.151 μm. In addition, the sample platelets had a contact angle of 66.0°. The gloss was found to be 41.9 gloss units (20°) and 159.8 gloss units (60°), and could thus be described as slightly matt. The pitting corrosion potential of the corrosion specimens was 386 mV.

3. Conclusion

[0204] The above-described comparison of a method of the invention and of a method of the generic type shows that the method of the invention leads to more corrosion-resistant products with very low reflectance (gloss).