Reaction Synthesis of Cr2AlC Ceramics Powders

摘要

Polycrystalline Cr2AlC was fabricated by a solid reaction synthesis of a mixture of Cr,Al and graphite powders in a flowing or the atmosphere in the temperature range of 700 to 1450 ℃.The products for identification and analysis were characterized by X-ray diffraction (XRD).The effects of the composition of the initial elemental powders and temperature of purity and formation of Cr2AlC were examined.It is found that the co-existence of Cr7C3 with Cr2AlC is attributed to the surplus ot carbon in the starting powders at 1350 ℃,selecting the starting materials with a Cr∶ Al∶ C molar ratio of 2∶ (1.1-1.6)∶ 1.For sample obtained from the starting elemental powders with the Cr∶ Al∶ C molar ratio of 2∶ 1.2∶ 0.94,no other phases but Cr2AlC were detected.In addition,the effect of temperature on the formation of Cr2AlC ceramic powders was carried out.