Thermal formation of corundum from aluminium hydroxides prepared from various aluminium salts

[摘要] Aluminium hydroxides have been precipitated from various aluminium salts and the differences in their thermal behaviour have been investigated. Pseudoboehmite derived from the nitrate, sulfate and chloride all form ð›�?-Al₂O₃ at ∼ 400°C but the formation of ð›�?-Al₂O₃ at 1200°C occurs more readily in the material derived from the sulfate. This contains a higher concentration of anionic impurities related to differences in the solubility of the original aluminium salts. The sulfate is retained in the gel to higher temperatures at which its eventual decomposition may lead to the formation of a reactive pore structure which facilitates the nucleation of ð›�?-Al₂O₃.

[学科分类] 材料工程

[关键词] Aluminium hydroxide;corundum;thermal transformation.