TWI414635B - Surface treatment of metal implants - Google Patents

Abstract

A high temperature acid liquor is firstly utilized to form uniform micrometer scale pores on surfaces of a titanium metal implant component, and a composite liquor containing hydrogen peroxide is utilized to perform deoxidation/ reoxidation treatment for the rough surface of the titanium metal implant to produce a layer of an uniform oxidation layer, thereby increasing biological compatibility of the implant.

Description

Surface treatment method for metal implants

The invention relates to a surface treatment method for a metal implant, in particular to a surface treatment method capable of forming micron-scale rough holes on the surface of a metal implant and forming a uniform oxide layer.

At present, there are various methods for forming a porous structure on the surface of a metal implant, such as sand blasting or acid etching, and the surface roughness of the metal implant can be increased by the above method. An implant surface having uniform roughness is created to promote bonding with bone tissue surrounding the implanted area.

For example, US Patent No. 6,491,723 discloses a surface treatment method for a metal implant, the surface treatment step of which is first acid etching using hydrofluoric acid (HF) to remove the surface natural oxide layer; A second acid etching was carried out with a high temperature sulfuric acid (H ₂ SO ₄ )/hydrochloric acid (HCl) mixture to form an irregular and uniform surface.

However, hydrofluoric acid is a very dangerous chemical that can enter the body through the mouth, nose, eyes or skin, causing hypocalcemia, hypomagnesemia, pulmonary edema, metabolic acidosis, ventricular arrhythmia, and even death. Severe symptoms of systemic poisoning. The sulfuric acid/hydrochloric acid mixture is a mixture of two strong acids, which will produce a vigorous exothermic dehydration reaction during preparation, which is easy to cause burns to the operator.

In view of the above, the present invention provides a surface treatment method for metal implants, which reduces the chance of dangerous damage to the human body during surface treatment and increases the biocompatibility effect.

The invention further provides a surface treatment method for a metal implant, the surface of the metal implant having a first oxide layer, the steps comprising: first, immersing the metal implant in a first acid solution to remove the first Oxide layer. Thereafter, the metal implant immersed in the first acid solution is taken out, and the metal implant is immersed in a second acid solution containing a hydrogen peroxide for roughening the metal implant. The surface forms a second oxide layer. Finally, the metal implant is removed from the second acid solution.

In an embodiment of the invention, the thickness of the second oxide layer is greater than 10 nm.

In an embodiment of the invention, the metal implant is made of a titanium metal, a titanium alloy or a metal containing a titanium element.

In an embodiment of the invention, the second acid solution further comprises a sulfuric acid or a hydrochloric acid.

In an embodiment of the invention, wherein the second acid solution is a mixed acid of hydrogen peroxide and sulfuric acid, the volume ratio of hydrogen peroxide to sulfuric acid in the mixed acid is 1:1 to 6:1, wherein peroxidation The concentration of hydrogen is 30% and the concentration of sulfuric acid is 95%.

In an embodiment of the invention, wherein the second acid solution is a mixed acid of hydrogen peroxide and hydrochloric acid, the volume ratio of hydrogen peroxide to hydrochloric acid in the mixed acid is 1:1 to 6:1, wherein peroxidation The concentration of hydrogen was 30% and the concentration of hydrochloric acid was 37%.

In an embodiment of the invention, the time during which the first acid solution is immersed is from several minutes to 60 minutes.

In an embodiment of the invention, the time during which the second acid solution is immersed is from several minutes to 24 hours.

In an embodiment of the invention, the treatment temperature when immersed in the first acid solution is from 60 ° C to 80 ° C.

In an embodiment of the invention, the treatment temperature when immersed in the second acid solution is from 20 ° C to 80 ° C.

In an embodiment of the invention, the first acid liquid is selected from the group consisting of nitric acid, hydrochloric acid and sulfuric acid.

In an embodiment of the invention, wherein the metal implant is immersed in the first acid solution, a rough hole of a plurality of micrometers is formed on the surface thereof.

In an embodiment of the invention, the surface roughness (Ra value) of the second oxide layer formed on the surface of the metal implant is about 0.3 to 0.7 μm.

In summary, the present invention firstly roughens the surface of the titanium metal implant with high-temperature hydrochloric acid or sulfuric acid to have micron-sized pores. At this stage, hydrochloric acid or sulfuric acid is mainly used to replace the highly dangerous hydrofluoric acid for the first etching, and at the same time, a rough surface is produced. And the mixture of hydrogen peroxide (H ₂ O ₂ )/sulfuric acid (H ₂ SO ₄ ) which is mildly reacted at room temperature is used for the second acid etching instead of the hydrochloric acid/sulfuric acid mixture which is subjected to high temperature operation to produce a vigorous reaction, so that Reduce the chance of dangerous harm to the human body.

The above described features and advantages of the present invention will be more apparent from the following description.

1 is a flow chart of a method of surface treatment of a metal implant according to an embodiment of the present invention. Wherein, the metal implant material may be a titanium metal, a titanium alloy or a metal containing titanium element, and after the metal implants are in contact with air, the surface thereof generally has an oxide layer, and the oxide layer may be a titanium oxide layer (TiO _2).

Referring to FIG. 1, the method for surface treatment of a metal implant comprises the following steps: First, performing a first acid etching treatment (step S100), immersing the metal implant in 37% by weight hydrochloric acid (HCl). In the solution, wherein the metal implant may be completely immersed or partially immersed in the above hydrochloric acid (HCl) solution to remove the surface oxide layer of the metal implant and form a plurality of micron-sized rough pores on the surface, and the first acid is related. The operating parameter of the etch treatment may be that the metal implant is allowed to act in a hydrochloric acid solution at a temperature of 60-80 ° C for several minutes to 60 minutes. In this embodiment, the action time of the metal implant in the hydrochloric acid solution is 10~ 30 minutes. Next, the metal implant is sequentially subjected to a process of rinsing and neutralizing, wherein the rinsing process can be washed and moistened with ultrapure water.

After the first acid etching treatment (step S100), a second etching treatment (step S200) is performed, that is, the metal implant which has been subjected to hydrochloric acid etching and neutralization treatment is immersed in a mixed acid. Among them, the mixed acid may be a mixed acid of hydrogen peroxide (30%) / sulfuric acid (95%) or a mixed acid of hydrogen peroxide (30%) / hydrochloric acid (37%).

It should be particularly noted that the mixed acid of hydrogen peroxide (30%) / sulfuric acid (95%) is mixed in an equal volume ratio or mixed in different volume ratios, wherein a volume ratio of hydrogen peroxide to sulfuric acid is preferably 1: 1~6:1. Similarly, the mixed acid of hydrogen peroxide (30%) / hydrochloric acid (37%) is mixed in equal volume ratio or mixed in different volume ratios, wherein the volume ratio of hydrogen peroxide to hydrochloric acid is preferably 1:1~6. :1.

The operating parameter for the second etching treatment may be that the metal implant is allowed to act in a mixed acid solution at room temperature for several minutes to 24 hours. In this embodiment, the action time of the metal implant in the mixed acid solution For -10 minutes, the last step is to rinse, neutralize and air dry. The washing process can be cleaned and moistened with ultrapure water.

After the second etching treatment, the metal implant has a second oxide layer formed on the surface thereof, and the second oxide layer may be a titanium oxide layer (TiO ₂ ). Among them, it is necessary to specifically specify the thickness of the oxide layer produced by the acid etching treatment, the size of which is greater than 10 nm, which is significantly different from the thickness of the natural oxide layer produced by the metal implant before the acid etching treatment.

Please refer to FIG. 2A and FIG. 2B respectively, which are respectively the surface SEM images of the metal implants treated by the above process, and the SEM magnifications are 2500 times and 5K times, respectively. As shown in Figs. 2A and 2B, it was found that the surface of the metal implant was an irregular and uniform rough surface formed by a plurality of tapered monomers which were slightly pointed, and each of the tapered monomers was approximately 1 to 3 μm apart. The surface roughness (Ra value) is about 0.3 to 0.7 μm.

Briefly, the first stage of the acid etching step of the present invention mainly replaces the hydrofluoric acid with a first acid solution such as hydrochloric acid at a high temperature to remove the surface natural oxide layer, and produces a micron-sized rough hole on the surface, and the first The second-stage acid etching step is mainly carried out by a second acid solution, such as a hydrogen peroxide/sulfuric acid mixture at room temperature, for a second acid etching treatment to perform deoxidation/reoxidation treatment to form a surface of the metal implant. A uniform layer of oxide. In this way, not only the violent reaction generated when using the acid solution or the acid solution is avoided, the risk is reduced, and a uniform and pure oxide layer is formed on the surface of the metal implant, which can be used to increase the biocompatibility of the implant. While the present invention has been described above in the foregoing embodiments, it is not intended to limit the invention, and the equivalents of the modification and retouching are still in the present invention without departing from the spirit and scope of the invention. Within the scope of patent protection.

S100, S200. . . Step flow

Figure 1 is a flow chart of a method of surface treatment of a metal implant of the present invention;

2A and 2B are surface SEM images of metal implants.

S100, S200. . . Step flow

Claims (10)

A surface treatment method for a metal implant, the surface of the metal implant having a first oxide layer, the step comprising: immersing the metal implant in a first acid solution to remove the first oxide layer, Wherein the first acid liquid is selected from the group consisting of hydrochloric acid and sulfuric acid; the metal implant immersed in the first acid liquid is taken out, and the metal implant is immersed in a second acid liquid. The second acid solution comprises a hydrogen peroxide and a hydrochloric acid for roughening the surface of the metal implant and forming a second oxide layer; and removing the metal implant from the second acid solution. The surface treatment method of claim 1, wherein the second oxide layer has a thickness greater than 10 nm. The surface treatment method according to claim 1, wherein the metal implant is made of a titanium metal, a titanium alloy or a metal containing a titanium element. The surface treatment method according to claim 1, wherein when the second acid solution is a mixed acid of hydrogen peroxide and hydrochloric acid, the volume ratio of hydrogen peroxide to hydrochloric acid in the mixed acid is 1:1. 6:1, wherein the concentration of hydrogen peroxide is 30%, and the concentration of hydrochloric acid is 37%. The surface treatment method according to claim 1, wherein the time of immersing in the first acid solution is from several minutes to 60 minutes. The surface treatment method according to claim 1, wherein the time of immersing in the second acid solution is from several minutes to 24 hours. The surface treatment method according to claim 1, wherein the treatment temperature when immersed in the first acid solution is from 60 ° C to 80 ° C. The surface treatment method according to claim 1, wherein the treatment temperature when immersed in the second acid solution is from 20 ° C to 80 ° C. The surface treatment method according to claim 1, wherein the metal implant is immersed in the first acid liquid, and a rough hole of a plurality of micrometers is formed on the surface thereof. The surface treatment method according to claim 1, wherein a surface roughness (Ra value) of the second oxide layer formed on the surface of the metal implant is about 0.3 to 0.7 μm.