RESEARCH STUDY TO DETERMINE THE PHASE EQUILIBRIUM RELATIONS OF SELECTED METAL CARBIDES AT HIGH TEMPERATURES
Rept. for Mar 1962-28 Feb 1963
UNION CARBIDE CORP PARMA OH
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This report is the result of investigations of phase equilibria in the binary systems, zirconium-carbon, tantalum-carbon, and boron-carbon. A completed phase diagram which encompasses experimental results and considerations heretofore unreported in the literature, is presented for the zirconium-carbon system. A tentative phase diagram for the tantalum-carbon system is included, which, in general, resembles the version released by Ellinger in 1943. Preliminary results for the boron-carbon system, depicting maximum solubility in the graphite lattice below the eutectic temperature of approximately 2390 C, are also included. The zirconium-carbon system is characterized by eutectic temperatures of 1850 and 2850 C on the zirconium-rich and carbon rich sides of ZrC, respectively. The tantalum carbon system is characterized by two high temperature phases, TaC and Ta2C. A eutectic is observed at 2825 C between Ta and Ta2C. Below the B4C-C eutectic temperature of 2390 C, maximum boron solubilities in graphite are found to be 1.50, 2.25, and 2.75 atomic per cent at temperatures of 2000, 2200, and 2350 C, respectively.
- Ceramics, Refractories and Glass