Patent ID: 7431777
Filing Date: 2008-10-07
Classification: C23C

Abstract:
1. A process for preparing a composition gradient cermet material comprising the steps of: in a first step, heating a metal alloy containing from 18 to 60 wt % chromium at a temperature in the range of about 600° C. to about 1150° C. in a hydrogen environment to form a heated metal alloy; in a second step, exposing said heated metal alloy to a reactive carbon gaseous environment comprising H in a third step, cooling said reacted alloy to a temperature below about 40° C. to provide a composition gradient cermet material, wherein one surface of the cermet is ceramic-rich and a second unexposed surface is metal-rich, and wherein said cooling step further comprises cooling said reacted alloy to a temperature in the range of 500° C. to 100° C., holding the temperature at any temperature in the range of 500° C. to 100° C. for a time period between 5 minutes to 10 hours and thereafter cooling at a rate in the range of 0.5° C. per second to 25° C. per second to below about 40° C.