ASSESSMENT OF THE REACTION OF SIC POWDERS WITH IRON-BASED ALLOYS

The degree of reaction and dispersion achieved when SiC powders are br ought into contact with liquid iron-based alloys has been assessed by a levitation dispersion test. SiC was found to react rapidly with molt en iron matrices to form iron silicides and graphite. Attempts to gene rate protective TiC or Al2O3 coatings on SiC in situ in liquid iron pr oved unsuccessful; neither was precoating SiC and Ni and/or Cu success ful in providing protection against molten iron alloys. Unprotected Si C also reacted readily with iron in the solid state (1000-1200-degrees -C). Precoating with Ni, however, provides protection and prevents SiC dissolution and silicide formation during sintering at such temperatu res.