THE LANTHANUM-CARBON SYSTEM
From thermal, metallographic, x-ray, dilatometric, and electrical resistance data a phase diagram is proposed for the La-C system. Two compounds are formed, body-centered-cubic La/sub 2/C/sub 3/ having a large range of solid solubility, and body-centered-tetragonal LaC/sub 2/. The former melts incongruently at 1415 C, and at 25 C it has an electrical resistivity about two and one-half times that of pure lanthanum. The latter melts congruently at 2356 C and at room temperature has an electrical resistivity about equal to that of pure lanthanum. The addition of carbon to La lowers the melting point of La about 115 C, raises the higher ( 6 wt.% Ru-U all - ) transformation about 10 C and appears to have no effect on the lower ( alpha - 6 wt.% Ru-U all ) transformation. The addition of carbon appears to lower the oxygen content in the metal and improve the machinability; however, the tendency to oxidize is increased. Two eutectics are formed in the system. The first occurs at 2.2% C and melts at 806 C, while the second occurs between LaC/sub 2/ and C with a melting point of 2271 C. (auth)
- Research Organization:
- Iowa State Coll., Ames; Los Alamos Scientific Lab., N. Mex.
- NSA Number:
- NSA-13-011914
- OSTI ID:
- 4273087
- Journal Information:
- Trans. Met. Soc. AIME, Journal Name: Trans. Met. Soc. AIME Vol. Vol: 215
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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