Method for growing an alumina surface on orthopaedic implant components

A process for ion beam treating a metallic orthopaedic implant component comprising:

• (a) immersing the implant component in an oxygen-containing gas at a pressure between 5.times.10.sup.-6 and 1.times.10.sup.-3 Torr;
• (b) applying an ion beam of aluminum to a surface of the immersed component to form an ion-implanted surface, and a graded interface layer of aluminum oxide at outer portions of the component, wherein the graded interface layer has a concentration of aluminum oxide that varies according to distance from the ion-implanted surface of the component and wherein the concentration increases in purity toward the ion-implanted surface of the component;
• (c) applying a source of heating to the immersed component using an independent radiant heating source while applying the ion beam in order to cause diffusion of the aluminum and oxygen, thereby facilitating formation of the aluminum oxide;
• and
• (d) applying a flux of aluminum or aluminum oxide vapor to the immersed component, so that the flux substantially equals a sputtered atoms flux induced by the ion beam of aluminum during formation of the interface.

A process for ion beam treating a metallic orthopaedic implant component comprising:

• (a) immersing the implant component in an oxygen containing gas at a pressure between 5.times.10.sup.-6 and 1.times.10.sup.-3 Torr;
• (b) applying an ion beam of aluminum atoms at an energy between 20 keV and 400 kev and at a current density of at least 10 microamperes/cm.sup.2 to a surface of the immersed component to form an ion-implantable surface;
• and
• (c) applying a source of heating to the immersed component using an independent radiant heating source to obtain a temperature between 400.degree. C. and 660.degree. C. while applying the ion beam, thereby inducing ion assisted diffusion of the implanted aluminum atoms and oxygen atoms of the oxygen-containing gas to provide an aluminum oxide graded interface layer of 50 .ANG. to 5000 .ANG. thick beneath the ion-implanted surface of at least one outer portion of the component and to provide a coincidentally grown aluminum oxide surface layer on the at least one outer portion of the ion-implanted surface of the component, wherein the graded interface layer has a concentration of aluminum oxide that varies according to distance from the ion-implanted surface of the component and wherein the concentration is nearly pure at the ion-implanted surface before the aluminum oxide surface layer is grown.

A process for ion beam treating a metallic orthopaedic implant component comprising:

• (a) immersing the implant component in an oxygen-containing gas at a pressure between approximately 5.times.10.sup.-6 Torr and approximately 1.times.10.sup.-3 Tort;
• (b) applying an ion beam of aluminum to a surface of the immersed component to form an ion-implanted surface, and a graded interface layer of aluminum oxide at outer portions of the component, wherein the graded interface layer has a concentration of aluminum oxide that varies according to distance from the ion-implanted surface of the component and wherein the concentration increases in purity toward the ion-implanted surface of the component;
• (c) applying a source of heating to the immersed component using an independent radiant heating source while applying the ion beam in order to cause diffusion of the aluminum and oxygen, thereby facilitating formation of the aluminum oxide;
• and
• (d) applying a source of aluminum or aluminum oxide vapor to the immersed component.