Bonded alumina coating for stainless steel

Patent metadata

Field	Value
Publication number	US-9757498-B2
Application number	US-201615041344-A
Country	US
Kind code	B2
Filing date	Feb 11, 2016
Priority date	May 21, 2014
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

A method for manufacturing an alumina-based layer structure having transition regions between layers is disclosed. The method may include ion milling a stainless steel structure surface to partially reduce a metal oxide layer from, and create an exposed portion of, the surface. The method may include oxidizing the exposed portion of the surface to form a crystallized metal oxide bonding layer, growing a crystallized alumina layer onto the metal oxide bonding layer, and diffusing metal from the surface into the crystallized alumina layer, to form a graded aluminate spinel layer. The method may include forming a first transition region from the graded aluminate spinel layer to a crystalline alumina layer, growing the crystalline alumina layer from the first transition region, forming a second transition region from the crystalline alumina layer to an amorphous alumina layer, and growing the amorphous alumina layer from the second transition region.

First claim

What is claimed is:

1. An apparatus comprising:
a stainless steel structure;
an at least partially polycrystalline alumina-based layer structure bonded to an exposed portion of the stainless steel structure, the layer structure including:
a crystallized metal oxide bonding layer formed on the exposed portion of the stainless steel structure;
a graded aluminate spinel layer formed on the crystallized metal oxide bonding layer, the graded aluminate spinel layer having:
metal diffused from the stainless steel surface;
and an at least partially polycrystalline structure;

a crystalline alumina layer;
a first transition region includes a metal concentration gradient extending from the graded aluminate spinel layer to the crystalline alumina layer;
an amorphous alumina layer; and
a second transition region includes a crystalline structure gradient extending from the crystalline alumina layer to the amorphous alumina layer.

2. The apparatus of claim 1 , wherein the apparatus is a medical device and the stainless steel structure comprises medical-grade stainless steel.

3. The apparatus of claim 1 , wherein the amorphous alumina layer is biologically inert.

4. The apparatus of claim 1 , wherein the alumina-based layer structure is atomically bonded to the stainless steel structure.

Assignees

• IBM

Inventors

• Biskeborn Robert G
• Lo Calvin S
• Rice Philip M
• Topuria Teya

Classifications

• A61L31/088

  Other specific inorganic materials not covered by A61L31/084 or A61L31/086 · CPC title

• C23C14/0084

  Producing gradient compositions · CPC title

• A61L31/022 Primary

  Metals or alloys · CPC title

• C23C14/0094

  in transition mode · CPC title

• A61L2430/02

  for reconstruction of bones; weight-bearing implants · CPC title