THE NIOBIUM—NIOBIUM CARBIDE SYSTEM1
THE NIOBIUM—NIOBIUM CARBIDE SYSTEM1
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DOI：
10.1021/j100839a029
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发表时间：
1960-10
期刊：
影响因子：
--
通讯作者：
E. Storms;N. Krikorian
中科院分区：
文献类型：
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作者：
E. Storms;N. Krikorian
测定了Nb-NbC相图的固相含量。测量以下特征温度：NbC/sub 0.08/和NbC/sub 0.39/之间的共晶温度为2335 ± 20 ℃，NbC/sub 0.52/和NbC/sub 0.56/之间的周晶温度为3090 ± 50 ℃，以及在约NbC/sub 0.86/处的熔点最大值为3500 ± 75 ℃。在2800 ℃下，在NbC/ sub 0.71附近的组成下，真空中发生一致蒸发。低于2000 ℃时，Nb/sub 2/C具有非常窄的均匀性范围。在相界平衡时Nb/sub 2/C相的晶格参数为a/sub 0/=3.128 ± 0.001 A，当NbC存在且a/sub 0/ = 3.126 ± 0.001、c/sub 0/ = 4.965 ± 0.001且检测到Nb相时，c/sub 0/ = 4.972 ± 0.001。在这两种情况下，c/a = 1.59。均匀性范围的狭窄似乎排除了在该区域中获得组成和晶格参数之间的可靠关系的可能性。（auth）
The solid pontion of the Nb--NbC phase diagram was determined. The following characteristic temperatures were measured: a eutectic temperature between NbC/sub 0.08/ and NbC/sub 0.39/ of 2335 plus or minus 20 deg C, a peritectic temperature between NbC/sub 0.52/ and NbC/sub 0.56/ of 3090 deg 50 deg C and a melting point maximum at about NbC/sub 0.86/ of 3500 plus or minus 75 deg C. Congruent vaporization in vacuo takes place at a composition near NbC/ sub 0.71/ at 2800 deg C. Below 2000 deg C Nb/sub 2/C has a very narrow range of homogeneity. Lattice parameters for the Nb/sub 2/C phase in equilibrium at the phase boundary were foundtobe a/sub 0/=3.128 plus or minus 0.001 A., c/sub 0/ =4.972 plus or minus 0.001A, when NbC was present and a/sub 0/ = 3.126 plus or minus 0.001, c/sub 0/ = 4.965 plus or minus 0.001 and the Nb phase was detected. In both cases c/a = 1.59. The narrowness of the homogeneity range seems to preclude the possibility of obtaining a reliable relationship between composition and lattice parameter in this region. (auth)