Surface modification of high temperature iron alloys
AssigneeThe University of Chicago
InventorJong-Hee Park
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Abstract
A method and article of manufacture of a coated iron based alloy. The method includes providing an iron based alloy substrate, depositing a silicon containing layer on the alloy surface while maintaining the alloy at a temperature of about 700.degree. C.-1200.degree. C. to diffuse silicon into the alloy surface and exposing the alloy surface to an ammonia atmosphere to form a silicon/oxygen/nitrogen containing protective layer on the iron based alloy.
Claims17
A method of preparing a coated iron based alloy, comprising the steps of:
- (a) providing an iron based alloy substrate having a surface;
- (b) depositing a silicon containing layer on said surface using a deposition source mixture of NaF--Si--SiO.sub.2 while maintaining said substrate at a temperature of at least about 700.degree. C.;
- and
- (c) while maintaining said substrate at the temperature of at least about 700.degree. C., exposing said silicon containing layer to an ammonia atmosphere to form said coated iron based alloy.
A method of preparing a stabilizing protective coating for iron based alloys, comprising the steps of:
- (a) providing an iron based alloy substrate having a surface;
- (b) depositing a silicon and oxygen containing layer on said surface being held at a temperature in the range of about 700.degree. C. to about 1200.degree. C. using a deposition source mixture of NaF--Si--SiO.sub.2 ;
- and
- (c) exposing said silicon and oxygen containing layer to a nitrogen containing atmosphere to form said stabilizing protective coating.
A method of preparing a coated iron-chromium alloy, comprising the steps of:
- (a) providing an iron chromium alloy having a surface available for coating;
- (b) depositing a silicon/oxygen containing layer on said surface using a deposition source, mixture of NaF--Si--SiO.sub.2 while maintaining said alloy at a temperature of about 700.degree.-1200.degree. C. and diffusing silicon into said iron chromium alloy;
- and
- (c) exposing said silicon/oxygen containing layer to a nitrogen containing atmosphere to form a silicon/oxygen/nitrogen containing coating on said iron-chromium surface.
Dependencies are inferred from the claim text.