# US 10,501,373 B1 · Multi-phase ceramic system

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- Number: US 10,501,373 B1
- Document ID: US10501373B1
- Status: Granted
- Kind: B1
- Application number: 15/363,140
- Filed: 2016-11-29
- Granted: 2019-12-10
- Earliest claimed: 2014-01-24
- Assignees: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
- Applicants: Frederick Dynys; Ali Sayir
- Inventors: Frederick Dynys; Ali Sayir
- Web page: https://patentgrep.com/patent/US10501373B1

## CPC

- C04B 35/10: based on aluminium oxide
- C04B 35/117: Composites
- A61F 2/30767: {Special external or bone-contacting surface, e.g. coating for improving bone ingrowth}
- A61F 2/3094: {Designing or manufacturing processes}
- A61F 2/32: for the hip
- A61F 2/34: Acetabular cups
- A61F 2/36: Femoral heads {; Femoral endoprostheses}
- A61L 27/10: Ceramics or glasses
- A61L 27/105: {containing Al2O3}
- A61L 27/427: {of other specific inorganic materials not covered by A61L27/422 or A61L27/425}
- A61L 27/50: Materials characterised by their function or physical properties {, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials}
- C04B 35/50: based on rare-earth compounds {(non-oxide rare earth compounds C04B35/5156)}
- C04B 35/6261: {Milling}
- C04B 35/6264: {Mixing media, e.g. organic solvents}
- C04B 35/64: Burning or sintering processes (C04B33/32 takes precedence {; powder metallurgy B22F})
- A61F 2002/30934: {Special articulating surfaces}
- A61F 2002/30968: {Sintering}
- A61F 2310/00203: containing alumina or aluminium oxide
- C04B 2235/3217: Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B 2235/3222: Aluminates other than alumino-silicates, e.g. spinel (MgAl2O4)
- C04B 2235/3224: Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
- C04B 2235/604: Pressing at temperatures other than sintering temperatures
- C04B 2235/6567: Treatment time
- C04B 2235/80: Phases present in the sintered or melt-cast ceramic products other than the main phase
- C04B 2235/96: Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- 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)

## Abstract

Systems, methods, and other embodiments associated with multi-phase ceramic composites are described herein. Specifically, a multi-phase ceramic composite having a microstructure having at least one solid-state lubricant phase and at least one wear resistant material phase.

## Claims

### Claim 1

A method for making a multi-phase ceramic composite, the method comprising;
providing a rare earth metal powder;
providing an Al2O3 powder;
mixing the rare earth metal powder first powder and the Al2O3 powder to form a mixed powder;
drying the mixed powder;
isostatically pressing the mixed powder to form a green component; and
sintering the green component to form a sintered component;
wherein the sintered component includes continuous networks of two phases, namely, a solid-state lubricant phase comprising gadolinium and a wear resistant phase comprising Al2O3, and wherein the two phases are randomly interspersed, wherein a molar ratio of the wear resistant phase to the solid state lubricant phase is between 0.3 and 2.0, wherein an entirety of the sintered component is constructed from constituents of the rare earth metal and Al2O3 powders.

### Claim 2 (depends on 1)

The method of claim 1, wherein the solid-state lubricant phase comprises Gd4Al2O9 or Gd2O3.

### Claim 3 (depends on 1)

The method of claim 1, wherein the mixing step is performed by wet milling the Al2O3 powder and the rare earth metal powder in ethanol.

### Claim 4 (depends on 3)

The method of claim 3, wherein the sintering step is performed at 1450 degrees C. for 4 hours in air.

### Claim 5 (depends on 1)

The method of claim 1, wherein the multi-phase ceramic composite comprises the solid-state lubricant phase, the wear resistant phase, and a third phase.

### Claim 6 (depends on 1)

The method of claim 1, further comprising using the multi-phase ceramic composite in a joint prosthesis.

### Claim 7 (depends on 6)

The method of claim 6, further comprising using the multi-phase ceramic composite on interacting surfaces of an artificial acetabular cup and a femoral head of a hip replacement.

### Claim 8 (depends on 1)

The method of claim 1, wherein the molar ratio is less than 1.0.

### Claim 9 (depends on 8)

The method of claim 8, wherein the solid state lubricant phase does not include aluminum.

### Claim 10

A method for making a multi-phase ceramic composite, the method comprising;
providing a Gd2O3 powder;
providing an Al2O3 powder;
mixing the Gd2O3 powder and the Al2O3 powder to form a mixed powder;
drying the mixed powder;
isostatically pressing the mixed powder to form a green component; and
sintering the green component to form a sintered component;
wherein the sintered component includes continuous networks of two phases, namely, a solid-state lubricant phase comprising Gd2O3 and a wear resistant phase comprising Al2O3, wherein the two phases are randomly interspersed throughout the multi-phase ceramic composite, wherein a molar ratio of the wear resistant phase to the solid state lubricant phase is between 0.3 and 2.0, wherein an entirety of the sintered component is constructed from constituents of the Gd2O3 powder and the Al2O3 powder.

### Claim 11 (depends on 10)

The method of claim 10, wherein the mixing step is performed by wet milling the Al2O3 powder and the Gd2O3 powder in ethanol.

### Claim 12 (depends on 11)

The method of claim 11, wherein the sintering step is performed at 1450 degrees C. for 4 hours in air.

### Claim 13 (depends on 10)

The method of claim 10, wherein the multi-phase ceramic composite comprises the at least one solid-state lubricant phase, the at least one wear resistant phase, and a third phase.

### Claim 14 (depends on 10)

The method of claim 10, further comprising using the multi-phase ceramic composite in a joint prosthesis.

### Claim 15 (depends on 14)

The method of claim 14, further comprising using the multi-phase ceramic composite on interacting surfaces of an artificial acetabular cup and a femoral head of a hip replacement.