Treatments to reduce frictional wear between components made of ultra-high molecular weight polyethylene and metal alloys

A method for making an orthopaedic implant comprising a metal alloy substrate in frictional contact with an ultra-high molecular weight polyethylene component, said method comprising the steps of:

• immersing said ultra-high molecular weight polyethylene component in an organic solvent for a first amount of time and at a temperature sufficient to dissolve polyethylene fibrils that are susceptible to frictional shearing off during use but insufficient to result in damage due to swelling of said ultra-high molecular weight polyethylene component, said organic solvent being selected from the group consisting of an aromatic hydrocarbon, an alicyclic hydrocarbon, an aliphatic hydrocarbon, and a mixture thereof;
• exposing said component to a vacuum at a pressure of about 10.sup.-3 torr for a second amount of time sufficient to remove residual solvent;
• exposing a substrate comprising a metal alloy selected from the group consisting of cobalt, nickel, titanium, zirconium, chromium, molybdenum, tungsten, platinum, palladium, and combinations thereof, to a vacuum at a pressure of about 10.sup.-5 torr or less;
• heating said substrate to about 300.degree. C. or, if said metal alloy is temperature sensitive, to a highest temperature acceptable for said metal alloy;
• depositing silicon onto said substrate to a thickness of between about 100-200 nm;
• substantially simultaneously bombarding said deposited silicon with a first energetic beam of nitrogen ions having a first energy of between about 10-30 keV at a first ion density and for a third amount of a time sufficient to form an inner bonding layer of metal-silicide cohesively bonded to an outer layer of silicon;
• cooling said substrate to about 80.degree. C.;
• condensing a diamond-like carbon precursor onto said outer layer of silicon for a fourth amount of time sufficient to form a film of precursor molecules on said outer layer of silicon;
• substantially simultaneously bombarding said diamond-like carbon precursor with a second energetic beam of nitrogen ions having a second energy of between about 10-30 keV at a second ion density and for a fifth amount of time sufficient to form a silicon carbide bonding layer cohesively bonded to an outer coating of diamond-like carbon.

A method for coating a metal alloy substrate with diamond-like carbon comprising:

• exposing said metal alloy substrate to a vacuum at a pressure of about 10.sup.-5 torr or less;
• heating said substrate to a first temperature of about 300.degree. C. or, if said metal alloy is temperature sensitive, to a highest temperature acceptable for said metal alloy;
• depositing silicon onto said substrate in an amount sufficient to form an inner bonding layer of metal-silicide cohesively bonded to an outer layer of silicon;
• substantially simultaneously bombarding said deposited silicon with a first energetic beam of ions at a first energy, a first ion density, and for a first amount of time sufficient to form said inner metal-silicide bonding layer cohesively bonded to said outer layer of silicon;
• condensing a diamond-like carbon precursor onto said outer layer of silicon at a second temperature and for a second amount of time sufficient to form a film of precursor molecules on said outer layer of silicon, wherein said second temperature is sufficiently low that said diamond-like carbon precursor is not vaporized off of said substrate;
• substantially simultaneously bombarding said diamond-like carbon precursor with a second energetic beam of ions at a second energy, a second ion density, and for a third amount of time sufficient to form an inner silicon carbide layer cohesively bonded to an outer coating of diamond-like carbon.

A method for coating a metal alloy substrate with diamond-like carbon comprising:

• providing a substrate comprised of a metal alloy selected from the group consisting of cobalt, nickel, titanium, zirconium, chromium, molybdenum, tungsten, platinum, palladium, and combinations thereof;
• exposing said substrate to a vacuum at a pressure of about 10.sup.-5 torr or less;
• heating said substrate to a first temperature of about 300.degree. C. or, if said metal alloy is temperature sensitive, to a highest temperature acceptable for said metal alloy;
• depositing silicon onto said substrate in an amount sufficient to form an inner bonding layer of metal-silicide cohesively bonded to an outer layer of silicon;
• substantially simultaneously bombarding said deposited silicon with a first energetic beam of ions at a first energy, a first ion density, and for a first amount of time sufficient to form said inner metal-silicide bonding layer cohesively bonded to said outer layer of silicon;
• condensing a diamond-like carbon precursor onto said outer layer of silicon at a second temperature and for a second amount of time sufficient to form a film of precursor molecules on said outer layer of silicon, wherein said second temperature is sufficiently low that said diamond-like carbon precursor is not vaporized off of said substrate;
• substantially simultaneously bombarding said diamond-like carbon precursor with a second energetic beam of ions at a second energy, a second ion density, and for a third amount of time sufficient to form an inner silicon carbide layer cohesively bonded to an outer coating of diamond-like carbon.

A method for making an orthopaedic implant comprising a metal alloy substrate in frictional contact with an ultra-high molecular weight polyethylene component, said method comprising the steps of:

• exposing a substrate comprising a metal alloy selected from the group consisting of cobalt, nickel, titanium, zirconium, chromium, molybdenum, tungsten, platinum, palladium, and combinations thereof, to a vacuum at a pressure of about 10.sup.-5 torr or less;
• heating said substrate to about 300.degree. C. or, if said metal alloy is temperature sensitive, to a highest temperature acceptable for said metal alloy;
• depositing silicon onto said substrate to a thickness of between about 100-200 nm;
• substantially simultaneously bombarding said deposited silicon with a first energetic beam of nitrogen ions having a first energy of between about 10-30 keV at a first ion density and for a third amount of a time sufficient to form an inner bonding layer of metal-silicide cohesively bonded to an outer layer of silicon;
• cooling said substrate to about 80.degree. C.;
• condensing a diamond-like carbon precursor onto said outer layer of silicon for a fourth amount of time sufficient to form a film of precursor molecules on said outer layer of silicon;
• substantially simultaneously bombarding said diamond-like carbon precursor with a second energetic beam of nitrogen ions having a second energy of between about 10-30 keV at a second ion density and for a fifth amount of time sufficient to form a silicon carbide bonding layer cohesively bonded to an outer coating of diamond-like carbon.

A method for coating a metal alloy orthopaedic component with diamond-like carbon comprising:

• exposing said metal alloy orthopaedic component to a vacuum at a pressure of about 10.sup.-5 torr or less;
• heating said component to a first temperature of about 300.degree. C. or, if said metal alloy is temperature sensitive, to a highest temperature acceptable for said metal alloy;
• depositing silicon onto said component in an amount sufficient to form an inner bonding layer of metal-silicide cohesively bonded to an outer layer of silicon;
• substantially simultaneously bombarding said deposited silicon with a first energetic beam of ions at a first energy, a first ion density, and for a first amount of time sufficient to form said inner metal-silicide bonding layer cohesively bonded to said outer layer of silicon;
• condensing a diamond-like carbon precursor onto said outer layer of silicon at a second temperature and for a second amount of time sufficient to form a film of precursor molecules on said outer layer of silicon, wherein said second temperature is sufficiently low that said diamond-like carbon precursor is not vaporized off of said component;
• substantially simultaneously bombarding said diamond-like carbon precursor with a second energetic beam of ions at a second energy, a second ion density, and for a third amount of time sufficient to form an inner silicon carbide layer cohesively bonded to an outer coating of diamond-like carbon.

A method for coating a metal alloy orthopaedic component with diamond-like carbon comprising:

• providing an orthopaedic component comprised of a metal alloy selected from the group consisting of cobalt, nickel, titanium, zirconium, chromium, molybdenum, tungsten, platinum, palladium, and combinations thereof;
• exposing said component to a vacuum at a pressure of about 10.sup.-5 torr or less;
• heating said component to a first temperature of about 300.degree. C. or, if said metal alloy is temperature sensitive, to a highest temperature acceptable for said metal alloy;
• depositing silicon onto said component in an amount sufficient to form an inner bonding layer of metal-silicide cohesively bonded to an outer layer of silicon;
• substantially simultaneously bombarding said deposited silicon with a first energetic beam of ions at a first energy, a first ion density, and for a first amount of time sufficient to form said inner metal-silicide bonding layer cohesively bonded to said outer layer of silicon;
• condensing a diamond-like carbon precursor onto said outer layer of silicon at a second temperature and for a second amount of time sufficient to form a film of precursor molecules on said outer layer of silicon, wherein said second temperature is sufficiently low that said diamond-like carbon precursor is not vaporized off of said component;
• substantially simultaneously bombarding said diamond-like carbon precursor with a second energetic beam of ions at a second energy, a second ion density, and for a third amount of time sufficient to form an inner silicon carbide layer cohesively bonded to an outer coating of diamond-like carbon.