Use of Bureau of Mines turbomill to produce high-purity ultrafine nonoxide ceramic powders.
Tuscaloosa, AL: U.S. Department of the Interior, Bureau of Mines, RI 8854, 1984 Jan; :1-12
Nonoxide ceramic materials could substitute for high-temperature alloy steels containing imported critical and strategic materials such as cobalt, chromium, and nickel if their high-temperature properties can be improved. An important result of this substitution would be a reduction of the nation's need for imports of critical and strategic materials. In this Bureau of Mines investigation, the primary objective was to produce high-purity ultrafine (particles < 5 um equivalent spherical diameter (esd)) alpha-silicon carbide (alpha-SiC) powders with improved high-temperature properties using the Bureau's patented turbomilling process. A secondary objective was to determine the feasibility of using polymer mill construction materials as a means of eliminating metal contamination from the turbomill. Ultrafine alpha-SiC powders with Brunauer-Emmett-Teller surface areas from 30 to 35 m2/g ( 0.06 microm particle esd) were produced in an all-polymer turbomill. These high-purity powders (with 1-pct B and 1-pct C additions) hot-pressed to greater than 99 pct of their optimal density and exhibited properties commensurate with those of commercially available alpha-SiC. The most promising of the construction materials tested for the major wear surfaces of the turbomill was ultra-high-molecular-weight polyethylene, a polymer thermoplastic.
Silicon-carbides; Ultrafines; Ceramics; Comminution; Turbomills; Nanotechnology
IH; Report of Investigations
NTIS Accession No.
Tuscaloosa, AL: U.S. Department of the Interior, Bureau of Mines, RI 8854