MANUFACTURE OF CERAMIC OR CERMET COMPOSITIONS

摘要

1363414 Granular ceramic or cermet materials ALBRIGHT & WILSON Ltd 27 July 1971 [31 July 1970] 37203/70 Headings C1A C1J and C1N Granular ceramic or cermet material is produced by slurrying at least one powdered ceramic material, optionally in admixture with at least one powdered metal in an aqueous solution of a thermally decomposable water-soluble metal compound other than chromium trioxide and forming the slurry into heat dried granules. In a modification alkali is added to an aqueous solution of a water soluble salt in which the powdered ceramic material has been slurried to precipitate a thermally decomposable hydroxide, basic salt or hydrated oxide, the consequent mixture being formed into heat dried granules. The powdered ceramic material may comprise Ni, Cr, Al, Zr, W, Ti, and/or Mg oxides or carbides. Many inorganic and organic thermally decomposable Ni, Cr, Zr, W, Mg, Ti, Al compounds are listed. In Examples 1-3 slurries of nickel oxide in nickel acetate solution are spray dried and then heated at 400‹ C. or 600‹ C. to decompose the nickel acetate (to NiO). In Example 4 alumina is slurried in ammonium dichromate solution, then spray dried and finally sprayed with a plasma torch. A slurry of chromia and chromium carbide in aqueous chromic nitrate (Example 5), a slurry of chromia and chromium metal in aqueous chromic acetate (Example 6), a slurry of titania in aqueous titanium tetrachloride (Example 7) and a slurry of magnesia in aqueous magnesium nitrate (Example 8) were utilized using the procedure of Example 4. Particle size details of both the powdered ceramic materials and the granules are given. The granular ceramic material or cermet material may be suitable for coating metal surfaces by plasma or flame spraying.