# US 2022/0033974 A1 · Surface-modified magnesium alloy

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- Number: US 2022/0033974 A1
- Document ID: US20220033974A1
- Status: Published application
- Kind: A1
- Application number: 17/486,372
- Filed: 2021-09-27
- Published: 2022-02-03
- Earliest claimed: 2019-03-28
- Assignees: Japan Medical Device Technology Co., Ltd.
- Applicants: Japan Medical Device Technology Co., Ltd.
- Inventors: Shuzo YAMASHITA; Makoto SASAKI; Akira WADA
- Web page: https://patentgrep.com/patent/US20220033974A1

## CPC

- C23C 28/00: Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
- C23C 28/04: only coatings of inorganic non-metallic material
- A61L 27/047: {Other specific metals or alloys not covered by A61L27/042 - A61L27/045 or A61L27/06}
- A61L 27/303: {Carbon}
- A61L 27/34: Macromolecular materials
- A61L 27/54: Biologically active materials, e.g. therapeutic substances {(A61L27/227 takes precedence)}
- A61L 27/58: Materials at least partially resorbable by the body
- A61L 31/024: {Carbon; Graphite}
- A61L 31/028: {Other inorganic materials not covered by A61L31/022 - A61L31/026}
- A61L 31/084: {Carbon; Graphite}
- A61L 31/10: Macromolecular materials
- A61L 31/148: {Materials at least partially resorbable by the body}
- A61L 31/16: Biologically active materials, e.g. therapeutic substances {(A61L31/047 takes precedence)}
- C22C 23/04: with zinc or cadmium as the next major constituent
- C23C 8/40: using liquids, e.g. salt baths, liquid suspensions
- C23C 8/42: only one element being applied
- C23C 8/80: After-treatment
- C23C 16/26: Deposition of carbon only
- C23C 16/505: using radio frequency discharges
- C23C 28/046: {with at least one amorphous inorganic material layer, e.g. DLC, a-C:H, a-C:Me, the layer being doped or not}
- A61L 2400/18: Modification of implant surfaces in order to improve biocompatibility, cell growth, fixation of biomolecules, e.g. plasma treatment
- A61L 2430/02: for reconstruction of bones; weight-bearing implants
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K)
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

To provide a magnesium alloy with improved corrosion resistance by surface modification, and a production method thereof. (1) The surface-modified magnesium alloy comprising: a magnesium alloy having an arbitrary shape; a magnesium fluoride layer formed by fluorination of the surface of the magnesium alloy; and a diamond-like carbon layer formed on the magnesium fluoride layer. (2) The method comprising: subjecting a surface of a magnesium alloy having an arbitrary shape to fluorination treatment to form a magnesium fluoride layer on the surface of the magnesium alloy, and then subjecting the magnesium alloy with the magnesium fluoride layer to be placed in a high-frequency plasma CVD device such that a source gas containing carbon is introduced to form a diamond-like carbon layer on the magnesium fluoride layer.

## Claims

### Claim 1

A surface-modified magnesium alloy comprising:
a magnesium alloy having an arbitrary shape;
a magnesium fluoride layer formed on the magnesium alloy via fluorination of a surface of the magnesium alloy; and
a diamond-like carbon layer formed on the magnesium fluoride layer.

### Claim 2 (depends on 1)

The surface-modified magnesium alloy according to claim 1, wherein the magnesium alloy contains, in % by mass, 0.95 to 2.00% Zn, 0.05% or more and less than 0.30% Zr, 0.05 to 0.20% Mn, and the balance consisting of Mg and unavoidable impurities, with an average crystal grain size of 1.0 to 3.0 μm and a standard deviation of grain size distribution of 0.7 or less.

### Claim 3 (depends on 1)

The surface-modified magnesium alloy according to claim 1, wherein the magnesium alloy has a wheel shape, a plate shape, a rod shape, a pipe shape, a band shape, a wire shape, a ring shape, or a combination of at least one shape as described above.

### Claim 4 (depends on 1)

The surface-modified magnesium alloy according to claim 1, wherein the surface-modified magnesium alloy is an alloy for orthopedic implants, an alloy for oral surgery implants, an alloy for plastic surgery implants, an alloy for cardiovascular surgery implants, or an alloy for cerebral surgery implants.

### Claim 5 (depends on 1)

The surface-modified magnesium alloy according to claim 1, wherein the surface-modified magnesium alloy is an alloy used (1) as therapeutic implants for non-luminal region, including for suture instruments such as clips, staplers, wires, and surgical needles, and for bone junction members such as bone pins, bone screws and suture anchors, or (2) as therapeutic implants for luminal region, including gastrointestinal and esophageal implants, and other therapeutic implants including circulatory stents, lower extremity stents, and aneurysm coils.

### Claim 6 (depends on 1)

The surface-modified magnesium alloy according to claim 1, wherein the magnesium fluoride layer has a layer thickness of 0.5 to 1.5 μm.

### Claim 7 (depends on 1)

The surface-modified magnesium alloy according to claim 1, wherein the diamond-like carbon layer has a layer thickness of 10 nm to 5 μm.

### Claim 8 (depends on 1)

The surface-modified magnesium alloy according to claim 1, wherein the diamond-like carbon layer is a silicon-containing diamond-like carbon layer.

### Claim 9 (depends on 1)

The surface-modified magnesium alloy according to claim 1, wherein a biodegradable polymer layer is formed on at least a part of the surface of the diamond-like carbon layer.

### Claim 10

A method of producing a surface-modified magnesium alloy comprising a magnesium fluoride layer on a surface of a magnesium alloy and a diamond-like carbon layer on the magnesium fluoride layer, the method comprising:
(1) subjecting a surface of a magnesium alloy having an arbitrary shape to fluorination treatment to form a magnesium fluoride layer on the surface of the magnesium alloy, and then
(2) subjecting the magnesium alloy with the magnesium fluoride layer to be placed in a high-frequency plasma CVD device such that a source gas containing carbon is introduced to form a diamond-like carbon layer on the magnesium fluoride layer.

### Claim 11 (depends on 10)

The method of producing a surface-modified magnesium alloy according to claim 10, wherein the source gas containing carbon further contains silicon, and a silicon-containing diamond-like carbon layer is formed on the magnesium fluoride layer.