查看文章

The chemical reactivity of boron carbide (B₄C) with metallic aluminium (Al) was studied at temperatures ranging from 900 to 1273 K (627–1000 °C). Al–B₄C powder mixtures were cold pressed, heated for 1–450 h under 10⁵ Pa of purified argon and characterized by X-ray diffraction (XRD) optical metallography (OM), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). Whatever the temperature in the investigated range, B₄C has been observed to react with solid or liquid Al. As long as the temperature is lower than 933 K (660 °C), i.e. as long as Al is in the solid state, interaction proceeds very slowly, giving rise to the formation of ternary carbide (Al₃BC) and to diboride (AlB₂). At temperatures higher or equal to 933 K, Al is in the liquid state and the reaction rate increases sharply. Up to 1141 ± 4 K (868 ± 4 °C), the reaction products are Al₃BC and AlB₂: at temperatures higher …