METHOD FOR THE SURFACE TREATMENT OF A METAL OR ALLOY PRODUCT, AND METAL OR ALLOY PRODUCT

Abstract

A process for the surface treatment and/or production of a metal or alloy product including the steps of: a) dulling of a surface of the metal or alloy product and b) electrochemical treatment of the dulled surface of the metal or alloy product, and a metal or alloy product which produced or able to be produced by the process.

Claims

1. A process for the surface treatment and/or production of a metal or alloy product, comprising the steps of: a) dulling a surface of the metal or alloy product to form a dulled surface; and b) electrochemically treating the dulled surface.

2. The process as claimed in claim 1, wherein grinding of the surface of the metal or alloy product is carried out before step a).

3. The process as claimed in claim 1, wherein a blasting medium is used for carrying out step a).

4. The process as claimed in claim 3, wherein the blasting medium comprises a metal or an alloy.

5. The process as claimed in claim 3, wherein the blasting medium is free of corners and/or edges, or the blasting medium comprises blasting medium bodies that are free of corners and/or edges.

6. The process as claimed in claim 1, wherein electropolishing of the dulled surface of the metal or alloy product is carried out in order to carry out step b).

7. The process as claimed in claim 1, wherein anodic pickling of the dulled surface of the metal or alloy product is carried out in order to carry out step b).

8. The process as claimed in claim 1, wherein step b) is carried out a number of times.

9. The process as claimed in claim 8, wherein step b) is each time carried out over a period of from 30 s to 120 s.

10. The process as claimed in claim 1, further comprising the step of: c) carrying out passivation of the dulled surface after step b).

11. The process as claimed in claim 10, wherein an aqueous passivating solution containing citric acid and/or nitric acid is used for carrying out step c).

12. The process as claimed in claim 10 wherein a step d) packaging of the metal or alloy product is carried out after step c) and a step cd) sterilization of the metal or alloy product is carried out between step c) and step d), or a step e) sterilization of the metal or alloy product is carried out after step d).

13. The process as claimed in claim 1, wherein the metal or alloy product consists of a steel.

14. The process as claimed in claim 1, wherein the metal or alloy product is a medical engineering product or an intermediate for a medical engineering product, or is a component of a medical engineering product.

15. A metal or alloy product produced or able to be produced by a process as claimed in claim 1.

16. The process as claimed in claim 1, further comprising the step of barrel finishing and/or belt grinding of the surface of the metal or alloy product before step a).

17. The process as claimed in claim 1, wherein a ductile and nonbrittle blasting medium is used for carrying out step a).

18. The process as claimed in claim 3, wherein the blasting medium comprises stainless steel.

19. The process as claimed in claim 3, wherein the blasting medium has a spherical and/or bead shape or comprises blasting medium bodies having a spherical and/or bead shape.

20. The process as claimed in claim 1, wherein the metal or alloy product comprises a non-rusting or corrosion-resistant stainless steel.

21. The process as claimed in claim 1, wherein the metal or alloy product comprises a martensitic corrosion-resistant stainless steel.

22. The process as claimed in claim 14, wherein the medical engineering product is a medical instrument, or the intermediate is an intermediate for a medical instrument, or the component is a component for a medical instrument.

23. The process as claimed in claim 22, wherein the medical instrument is a surgical instrument.

24. The process as claimed in claim 14, wherein the intermediate is a semifinished part, a blank or a partly manufactured part.

Description

DETAILED DESCRIPTION

[0167] Further features and advantages of the invention are derived from the following description of preferred embodiments with the aid of examples. Here, features of the invention can be realized in each case either alone or in combination with one another. The embodiments described below serve to further illustrate the invention without restricting it thereto.

EXAMPLES

1. Surface Treatment of a Surgical Instrument or Representative Test Specimens Thereof by a Process According to the Invention

[0168] The test specimens used were produced from the identical material and using the identical manufacturing steps as the surgical instruments (e.g. clamps, needle holders, shears with cemented carbide and the like).

[0169] SEM/EDX analyses (foreign material and doubling of material) were carried out on the corrosion specimens and instruments.

[0170] Potentiodynamic tests (pit corrosion potential) were firstly only carried out on test specimens. To analyze the benchmark and, for comparison, whether the measured values measured on test specimens can be carried over to the instrument, instruments were measured in a laboratory. The results of the test specimens were confirmed here.

[0171] Contact angle measurements (contact angles) were partly carried out on the instrument (flat surface without shadowing), but preferably on test plates since the fluctuations were less significant here.

[0172] A surgical instrument (clamp BH110R), corrosion test specimens and test plates were firstly treated by means of barrel finishing for a period of four hours. After this, the surgical instrument and the test specimens were allowed to brighten over a period of one hour. Both the instrument and the test specimens were made of the identical material.

[0173] The surgical instrument and the test specimens were then treated by means of particle blasting. As blasting media, use was made of stainless steel beads (cast stainless steel Cr-Shot Beta 30) having an average bead diameter of from 200 μm to 400 μm. An injector blasting unit was used for the blasting operation. Blasting was carried out under a pressure of 4 bar.

[0174] The surface of the surgical instrument and of the test specimens was subsequently electropolished. This was carried out at a DC voltage of 4.5 volt. Electropolishing was carried out over a period of 45 seconds at a temperature of 80° C.

[0175] The surface of the surgical instrument and of the test specimens was subsequently passivated. For this purpose, the surgical instrument and the test specimens were dipped into 33% strength nitric acid. Passivation was carried out over a period of 30 minutes at a temperature of 30° C.

[0176] After conclusion of the surface treatment of the surgical instrument and the test specimens, no doubling of material or overlap of material and also no transfer of foreign material were able to be determined. The corrosion test specimens had a pit corrosion potential of 550 mV. The test plates had a contact angle of 86.0°.

2. Surface Treatment of a Surgical Instrument by Means of a Generic Process

[0177] A surgical instrument (clamp BH110R), corrosion test specimens and test plates were firstly treated by means of barrel finishing over a period of four hours. The surgical instrument and the test specimens were then allowed to brighten over a period of one hour.

[0178] The surgical instrument and the test specimens were then treated by means of particle blasting. Glass beads having an average diameter of from 40 μm to 70 μm were used for this purpose. Blasting was carried out in an injector blasting unit under a pressure of 4 bar.

[0179] The surgical instrument and the test specimens were subsequently subjected to passivation. A 10% strength citric acid solution was used for this purpose. Passivation was carried out over a period of 10 minutes at a temperature of 55° C.

[0180] After conclusion of the surface treatment of the surgical instrument and the test specimens, much doubling of material and overlap of material were able to be found. In addition, a transfer of foreign material of 1.4% could be detected. The pit corrosion potential of the corrosion test specimens was 386 mV. In addition, the test plates had a contact angle of 74.4°.

3. Conclusion

[0181] The above-described comparison of a process according to the invention and a generic process shows that the process according to the invention leads to more corrosion-resistant and in particular more scratch-resistant products. In addition, the process according to the invention is suitable for decreasing the risk of the occurrence of surface discoloration compared to generic processes. Furthermore, the process according to the invention leads to products which can be cleaned more easily (see measured contact angles).