METHOD FOR FORMING SUPERHYDROPHILIC OXIDE FILM ON PURE TITANIUM SURFACE

Abstract

The present disclosure relates to a method for forming a superhydrophilic oxide film on a pure titanium surface, and has the effect capable of realizing superhydrophilicity with a contact angle of 20 or less by optimizing time and voltage under anodization treatment conditions.

Claims

1. A method for forming a superhydrophilic oxide film on a titanium surface, the method comprising the steps of: polishing the titanium (Ti) surface (step 1); and anodizing polished titanium (Ti) at 10 to 110 V for 1 to 30 minutes to form an oxide film on the titanium surface (step 2).

2. The method of claim 1, wherein titanium is pure titanium of any one of Ti grades 1 to 4 having a Ti content of 99 wt. % or more.

3. The method of claim 1, wherein the polishing in the step 1 is one or more of electrochemical polishing and chemical polishing.

4. The method of claim 1, wherein the anodized electrolyte in the step 2 is a mixture of NH.sub.4F, water, and ethylene glycol.

5. The method of claim 1, wherein the step 2 is anodizing polished titanium (Ti) at 90 to 110 V for 5 to 15 minutes.

6. The method of claim 5, wherein the step 2 is anodizing polished titanium (Ti) at 95 to 105 V for 7 to 13 minutes.

7. The method of claim 6, wherein the step 2 is anodizing polished titanium (Ti) at 99.5 to 102 V for 9.5 to 11 minutes.

8. The method of claim 7, wherein the superhydrophilic oxide film has superhydrophilicity with a contact angle of 20 or less.

9. Titanium on which a superhydrophilic oxide film prepared by the method of claim 1 is formed.

10. Titanium on which an oxide film having a surface roughness value of an average roughness of 15 or more and a root mean square roughness (RMS) of 20 or more prepared by the method of claim 1 is formed.

11. A medical device containing titanium manufactured by the method of claim 1.

12. A biotransplantation material containing titanium manufactured by the method of claim 1.

13. An aviation part containing titanium manufactured by the method of claim 1.

14. An aerospace part containing titanium manufactured by the method of claim 1.

15. A precision machine part containing titanium manufactured by the method of claim 1.

16. A plant part containing titanium manufactured by the method of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 is images obtained by photographing with a scanning electron microscope (SEM) surface shapes of oxide films obtained by applying a voltage level of 10 to 100 V with an anodization treatment time of pure titanium fixed at 10 minutes.

[0029] FIG. 2 is images obtained by photographing with a scanning electron microscope (SEM) thicknesses of oxide films obtained by applying a voltage level of 10 to 100 V with an anodization treatment time of pure titanium fixed at 10 minutes.

[0030] FIG. 3 shows images and surface roughness values obtained by measuring, with an atomic force microscope (AFM), oxide films obtained by applying a voltage level of 10 to 100 V with an anodization treatment time of pure titanium fixed at 10 minutes.

[0031] FIG. 4 is images of evaluating contact angles after a drop of water is dropped to oxide films obtained by applying a voltage level of 10 to 100 V with an anodization treatment time of pure titanium fixed at 10 minutes.

DETAILED DESCRIPTION

[0032] Hereinafter, the present disclosure will be described in more detail by the following Examples. However, the following Examples are only to illustrate the present disclosure, and the content of the present disclosure is not limited by the following Examples.

<Example> Anodization Treatment of Ti Grade 4 Pure Titanium

[0033]

TABLE-US-00002 Ti grade 4; pure titanium Component C Fe H N O Ti wt. % Max 0.1 Max 0.5 Max 0.015 Max 0.05 Max 0.4 99 Physical properties Density 4.51 g/cc Mechanical Hardness, Brinell 265 (annealed) properties Hardness, Knoop .sup.215 (unwelded sheet) Hardness, Rockwell B 100 (annealed) Hardness, Rockwell B .sup.23 (unwelded sheet) Hardness, Rockwell C 23 Hardness, Vickers 280 Tensile Strength, Ultimate 550 MPa Tensile Strength, Yield 480-552 MPa

[0034] After degreasing the pure titanium substrate using acetone and ethanol, electrochemical polishing and chemical polishing were sequentially performed as shown in Table 1 below.

[0035] Next, anodization treatment was performed under the conditions as shown in Table 1 below.

TABLE-US-00003 TABLE 1 Degreasing Polishing Anodizing Solution Acetone {circle around (1)}Electrochemical polishing .fwdarw. Electrolyte 0.25 wt. % NH.sub.4F + Ethanol {circle around (2)}Chemical polishing 2 vol. % H.sub.20 in 150 ml ethylene glycol {circle around (1)}Electrochemical polishing Temperature 0 C. Solution CH.sub.3COOH:H.sub.2SO.sub.4:HF = Anode Ti grade 4 60:15:23 (in volume) Duration 10 min Temperature 20 C. Cathode Platinum Duration 1 min Distance 3 cm Constant 1.40 A/cm.sup.2 Stirrer 100 rpm current density speed {circle around (2)}Chemical polishing Duration 1~10 min Solution HF:HNO.sub.3 = 1:3 Voltage 10~100 V (in volume) Duration 10 sec

[0036] Recognizing that 10 minutes as the anodization treatment time in this embodiment is the most optimal condition for realizing superhydrophilicity, in the following experimental examples, and experiments were conducted to find out the optimum conditions for fixing the anodization treatment time at 10 minutes, adjusting the applied voltage, and realizing superhydrophilicity.

<Experimental Example 1> Shape Evaluation of Oxide Films Obtained by Performing Anodization Treatment

[0037] Experiments were conducted to find out the surface shape, thickness, and roughness of the oxide film formed on the surface of pure titanium that had completed anodization treatment in Examples.

[0038] FIG. 1 is images obtained by photographing with a scanning electron microscope (SEM) surface shapes of oxide films obtained by applying a voltage level of 10 to 100 V with an anodization treatment time of pure titanium fixed at 10 minutes.

[0039] As shown in FIG. 1, pores are not formed on the surface of the sample to which 10 to 30 V is applied, but pores are formed on the surface of the sample to which 40 to 100 V is applied. In particular, it can be confirmed that the pores are formed to the largest pore size of about 30.22 nm in the sample to which 100 V was applied.

[0040] FIG. 2 is images obtained by photographing with a scanning electron microscope (SEM) thicknesses of oxide films obtained by applying a voltage level of 10 to 100 V with an anodization treatment time of pure titanium fixed at 10 minutes. As shown in FIG. 2, the thickness of the oxide film tends to increase as the applied voltage level increases. In particular, it can be confirmed that the thickness of the oxide film is remarkably improved when the voltage level is increased from 90 to 100 V.

[0041] FIG. 3 shows images and surface roughness values obtained by measuring, with an atomic force microscope (AFM), oxide films obtained by applying a voltage level of 10 to 100 V with an anodization treatment time of pure titanium fixed at 10 minutes.

[0042] As shown in FIG. 3, the roughness of the oxide film showed various roughnesses depending on the applied voltage level so that no particular tendency was shown, and it can be confirmed that the roughness is shown to be particularly remarkably high in the 100 V sample.

<Experimental Example 2> Hydrophilicity Evaluation

[0043] In order to find out the hydrophilicity of the samples subjected to anodization treatment in Examples, contact angle experiments were performed. The experiment was performed 5 times in total to obtain an average value.

[0044] FIG. 4 is images of evaluating contact angles after a drop of water is dropped to oxide films obtained by applying a voltage level of 10 to 100 V with an anodization treatment time of pure titanium fixed at 10 minutes.

[0045] As shown in FIG. 4, the polished sample before anodization treatment showed a contact angle of 92.1, and as the applied voltage level increases from 50 V or more, the contact angle decreases so that the hydrophilic tendency is shown to be stronger. In particular, the change in the contact angle is shown to be large in the sample where the applied voltage is increased from 90 to 100 V, and the contact angle of about 9.5 is shown in the 100 V sample so that superhydrophilicity may be confirmed to be realized. In general, for those skilled in the art, superhydrophilicity means having a contact angle of 20 or less, and it is well known that it is not easy to realize superhydrophilicity.

[0046] In summary of the results of Experimental Examples 1 and 2, the contact angle of the oxide film surface is thought to be caused by the correlation between two factors, pore size and roughness, and it can be seen that the larger the pore size, or the larger the roughness value, the lower the contact angle. Even if the roughness value is small, the contact angle can be thought to be lowered by complementing this if the pore size becomes large.

[0047] Hereinafter, an experiment was conducted to derive anodization treatment conditions for implementing superhydrophilicity in Experimental Example 3.

<Experimental Example 3> Derivation of Anodization Treatment Conditions (Time and Voltage) for Implementing Superhydrophilicity

(1) Optimization of Anodization Treatment Time

[0048] In Examples, the average values obtained by measuring five times the contact angles of the samples obtained by fixing the applied voltage to 100 V and adjusting only the time are shown in Table 2 below.

TABLE-US-00004 TABLE 2 Anodization Example Voltage (V) Time (min) Contact angle () 1-1 100 8.5 42 2.6 1-2 9 33 3.5 1-3 9.5 16 3.1 1-4 10 9.5 1.6 1-5 10.5 12 4.3 1-6 11 15 3.3 1-7 11.5 46 4.1

[0049] As shown in Table 2 above, it can be confirmed that superhydrophilicity is implemented in the samples treated for 9.5 to 11 minutes.

(2) Optimization of Anodization Treatment Voltages

[0050] In Examples, the average values obtained by measuring five times the contact angles of the samples obtained by fixing the treatment time to 10 minutes and adjusting only the applied voltage level are shown in Table 3 below.

TABLE-US-00005 TABLE 3 Anodization Examples Voltage (V) Time (min) Contact angle () 2-1 98.5 10 35.8 2.9 2-2 99 31.8 2.7 2-3 99.5 11.8 2.5 2-4 100 9.5 1.6 2-5 100.5 12.4 3.4 2-6 101 12.9 2.7 2-7 101.5 14.1 3.5 2-8 102 15.9 3.4 2-9 102.5 41.7 3.6

[0051] As shown in Table 3 above, it can be confirmed that superhydrophilicity is implemented in the samples treated at 99.5 to 102 V.

[0052] Comprehensively, it can be confirmed that a superhydrophilic oxide film with a contact angle of 20 or less is formed on the pure titanium surface subjected to anodization treatment by applying a voltage of 99.5 to 102 V for 9.5 to 11 minutes.

[0053] So far, the present disclosure has been looked at with respect to its preferred embodiments. Those skilled in the art to which the present disclosure pertains will be able to understand that the present disclosure can be implemented in a modified form without departing from the essential characteristics of the present disclosure. Therefore, the disclosed embodiments should be considered from an illustrative point of view rather than a limiting point of view. The scope of the present disclosure is shown in the claims rather than the foregoing description, and all differences within the scope equivalent thereto will be construed as being included in the present disclosure.