Chromia spray powders and a process for making the same
AssigneeSaint-Gobain Ceramics & Plastics, Inc.
InventorsSung H. Yu, Howard Wallar
Life of this patent
Estimating the term…
Abstract
Particles particularly useful for thermal spraying a wear resistant coating on to a substrate comprise an essentially single phase crystalline structure comprising from 45 to 100% by weight of chromia and from 0 to 55% by weight of alpha alumina.
Claims9
An essentially single-phase, thermosprayable powder comprising from 45 to 100% chromia and correspondingly from 0 to 55% of alpha alumina, all proportions being by weight, and less than 200 ppm of each of any compound effective to stabilize chromium inn the hexavalent state.
A process for the production of a thermosprayable powder which comprises mixing an alumina powder having a content of alkali metal and alkaline earth metal oxide impurities of not more than 120 ppm of each, with a chromia powder also having less than 120 ppm of any impurity effective to stabilize chromium in the hexavalent state, the powders being mixed in proportions to give, upon firing, an essentially single phase crystalline powder comprising from 45 to 99% of chromia and from 55 to 1% of alpha alumina, all proportions being by weight, and firing the mixture at a temperature of from 1300 to 1500° C. to produce the said essentially single-phase crystalline powder.
Dependencies are inferred from the claim text.