# US 9,414,924 B2 · Ceramic layered medical implant

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- Number: US 9,414,924 B2
- Document ID: US9414924B2
- Status: Granted
- Kind: B2
- Application number: 13/853,336
- Filed: 2013-03-29
- Published: 2013-09-05
- Granted: 2016-08-16
- Earliest claimed: 2007-06-11
- Assignees: Smith & Nephew, Inc.
- Applicants: Smith & Nephew, Inc.
- Inventors: Vivek Devidas Pawar; Shilesh C. Jani; Carolyn L. Weaver
- Web page: https://patentgrep.com/patent/US9414924B2

## CPC

- A61F 2/30767: {Special external or bone-contacting surface, e.g. coating for improving bone ingrowth}
- A61L 27/047: {Other specific metals or alloys not covered by A61L27/042 - A61L27/045 or A61L27/06}
- A61L 27/306: {Other specific inorganic materials not covered by A61L27/303 - A61L27/32}
- C23C 8/34: more than one element being applied in more than one step
- A61C 3/00: Dental tools or instruments (implanting tools A61C8/00; tools for fastening artificial teeth A61C13/12; visual inspection devices, e.g. dental mirrors, A61B1/24)
- A61F 2/30: Joints
- A61F 2/32: for the hip
- A61F 2/38: for elbows or knees
- A61F 2/44: for the spine, e.g. vertebrae or spinal discs
- A61F 2002/30922: {Hardened surfaces}
- A61F 2002/30929: {having at least two superposed coatings}
- A61F 2002/30934: {Special articulating surfaces}
- A61F 2310/00089: Zirconium or Zr-based alloys
- A61F 2310/00634: Coating made of zirconium oxide or hydroxides
- A61F 2310/00892: Coating made of zirconium nitride
- A61L 2400/18: Modification of implant surfaces in order to improve biocompatibility, cell growth, fixation of biomolecules, e.g. plasma treatment
- A61L 2420/02: Methods for coating medical devices
- A61L 2430/02: for reconstruction of bones; weight-bearing implants
- A61L 2430/24: for joint reconstruction
- C01B 3/04: by decomposition of inorganic compounds (reversible storage of hydrogen C01B3/0018)
- C21D 1/09: by direct application of electrical or wave energy; by particle radiation
- Y02E 60/36: Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)
- 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)
- 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)
- A61C: DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE (non-driven toothbrushes A46B; {tongue scrapers A61B17/24;} preparations for dentistry A61K6/00; preparations for cleaning the teeth or mouth A61K8/00, A61Q11/00)
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A new composition and medical implant made there from comprises a thick diffusion hardened zone, and layered ceramic surface. Orthopedic implants comprising the new composition, methods of making the new composition, and methods of making orthopedic implants comprising the new composition are disclosed.

## Claims

### Claim 1

A method of making a layered ceramic medical implant comprising the steps of:
forming said medical implant of zirconium or zirconium alloy; and
forming a multi-layered diffusion hardened zone in said medical implant beneath a multi-layered ceramic coating, said multi-layered ceramic coating including at least a first ceramic layer and a second ceramic layer, the first ceramic layer having a composition that is different than the second ceramic layer, said step of forming said multi-layered diffusion hardened zone and said multi-layered ceramic coating including:
treating said medical implant in the presence of one or more ceramic-forming species at temperature of 500 to 1000° C. for greater than 2 minutes, and
thereafter treating said medical implant under a reactive gas at a temperature of 500 to 700° C. to diffuse at least a portion of the one or more ceramic-forming species into the zirconium or zirconium alloy, the reactive gas being different than the one or more ceramic-forming species.

### Claim 2 (depends on 1)

The method of claim 1, wherein the steps of treating said medical implant in the presence of one or more ceramic-forming species at temperature of 500 to 1000° C. for greater than 2 minutes, and thereafter treating said implant under a reactive gas at a temperature of 500 to 700° C. are repeated.

### Claim 3 (depends on 1)

The method of claim 1, wherein the step of treating said medical implant in the presence of one or more ceramic-forming species at temperature of 500 to 1000° C. for greater than 2 minutes is performed for between 5 minutes and 12 hours.

### Claim 4 (depends on 1)

The method of claim 1, wherein the step of thereafter treating said medical implant under a reactive gas at a temperature of 500 to 700° C. is performed for between 15 minutes to 30 hours.

### Claim 5 (depends on 1)

The method of claim 1, wherein the step of thereafter treating said medical implant under a reactive gas is carried out in nitrogen.

### Claim 6 (depends on 1)

The method of claim 1, wherein the step of thereafter treating said medical implant under a reactive gas is carried out in methane.

### Claim 7 (depends on 1)

The method of claim 1, wherein the step of treating said medical implant in the presence of one or more ceramic-forming species at temperature of 500 to 1000° C. is carried out by placing said medical implant in a solid reactive mixture.

### Claim 8 (depends on 1)

The method of claim 1, wherein the step of treating said medical implant in the presence of one or more ceramic-forming species at temperature of 500 to 1000° C. for greater than 2 minutes is carried out in a nitrogen atmosphere.

### Claim 9 (depends on 1)

The method of claim 1, wherein the step of treating said medical implant in the presence of one or more ceramic-forming species at temperature of 500 to 1000° C. for greater than 2 minutes is carried out in a nitrogen and argon mixture.

### Claim 10 (depends on 1)

The method of claim 1, wherein, the step of treating said medical implant in the presence of one or more ceramic-forming species at temperature of 500 to 1000° C. for greater than 2 minutes is carried out in a methane and nitrogen mixture.

### Claim 11 (depends on 1)

The method of claim 1, wherein said reactive gas is present at a partial pressure of from 10−4 to 760 Torr.

### Claim 12 (depends on 1)

The method of claim 1, wherein said reactive gas is present at a partial pressure from 0.05 to 500 Torr.

### Claim 13 (depends on 1)

The method of claim 1, wherein said step of treating said medical implant in the presence of one or more ceramic-forming species at temperature of 500 to 1000° C. for greater than 2 minutes and said step of thereafter treating said medical implant under a reactive gas at a temperature of 500 to 700° C. comprise treating said medical implant with a diffusion hardening species selected from the group consisting of oxygen, nitrogen, boron, carbon, and any combination thereof.

### Claim 14 (depends on 13)

The method of claim 13, further comprising subjecting the medical implant to surface preparation techniques to form adherent oxide.

### Claim 15

A method of making a layered ceramic medical implant comprising the steps of:
forming said medical implant of zirconium or zirconium alloy;
treating said implant in the presence of ceramic-forming species at temperature of 500 to 1000° C. for greater than 2 minutes; and, thereafter treating said implant under a reactive gas at a temperature of 500 to 1000° C.; and
oxidizing a Zirconium-2.5 wt % niobium alloy sample in a convection furnace in air at 635° C. for 110 minutes, placing the sample in a vacuum furnace and controlling the partial pressure of nitrogen, pumping the pressure of the furnace under 10−4 Torr, heating the sample to 685° C. in approximately 1 hour, introducing high purity nitrogen gas and maintaining the partial pressure between 400 to 500 mTorr, maintaining the sample under an atmosphere of nitrogen at a temperature of 685° C. for 7.5 hours, cooling the sample to room temperature under nitrogen atmosphere in 30 minutes; and sectioning the sample and evaluating the sample using metallographic techniques.

### Claim 16 (depends on 1)

The method of claim 1, wherein the first ceramic layer comprises the zirconium or zirconium alloy and one of the one or more of the ceramic-forming species, and the second ceramic layer comprises zirconium or zirconium alloy and two of the one or more of the ceramic-forming species.

### Claim 17 (depends on 16)

The method of claim 16, wherein the step of forming said multi-layered diffusion hardened zone and said multi-layered ceramic coating further includes forming a first layer and a second layer of the multi-layered diffusion hardened zone.

### Claim 18 (depends on 17)

The method of claim 17, wherein the step of forming said multi-layered diffusion hardened zone and said multi-layered ceramic coating further includes forming a third ceramic layer of the multi-layered ceramic coating at a surface of the medical implant, the third ceramic layer comprising nitrogen and zirconium or zirconium alloy.