Oxidation of ultrafine boron carbide, vanadium carbide, and chromium carbide powders
Oxidation of ultrafine boron carbide, vanadium carbide, and chromium carbide powders
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超细碳化硼、碳化钒、碳化铬粉末的氧化
DOI：
10.1007/bf00802637
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
A. Kornilov
中科院分区：
文献类型：
--
作者：
Yu. L. Krut;G. V. Galevskii;A. Kornilov
这些化合物在空气中的热力学稳定性按B~ C<Cr 3C 2 < VC的顺序增加（碳化铬和碳化钒的稳定性几乎相同）[3]。表i中引用了通过通常的碳热法生产的粉末形式的这些碳化物的氧化的文献数据。碳化硼在空气中的抗氧化性（实际上相对较高）与其颗粒上液体氧化硼的不可渗透膜的外观有关，这可以防止氧气到达它们[7]。因此，只有在高温下，当氧化硼的蒸发变得明显时，B~ C才发生完全氧化（表I）。碳化物的化学成分通过标准技术测定[7]。粉末的平均粒度用表达式[8]计算
The thermodynamic stability of these compounds in air increases in the order B~ C< Cr3C2< VC (the stabilities of chromium carbide and vanadium carbide are practically identical)[3]. Literature data on the oxidation of these carbides in the form of powders produced by the usual carbothermic method are cited in Table i. The oxidation resistance of boron carbide in air (which is in fact comparatively high) is linked with the appearance on its grains of impervious films of liquid boron oxide, which prevent oxygen from reaching them [7]. Because of this, full oxidation of B~ C takes place only at elevated temperatures (Table I), when evaporation of the boron oxide becomes appreciable.In the work described below, a study was made of the atmospheric oxidation of ultrafine boron carbide, vanadium carbide, and chromium carbide powders produced by the gaseousphase method. The chemical compositions of the carbides were determined by standard techniques [7]. The mean particle sizes of the powders were calculated with the expression [8]