不同酸催化溶胶-凝胶法制备负热膨胀ZrW_2O_8粉体及其性能

Preparation and Property of Negative Thermal Expansion ZrW_2O_8 Powder by Sol-Gel Method with Different Acid Catalysts

分别以HAc、HClO_4、H_2SO_4、H_3PO_4、(NH_4)_2HPO_4、HCl和HNO_3为催化剂,以硝酸氧锆和钨酸铵为原料,采用溶胶-凝胶法制备ZrW_2O_8粉体,分析了不同酸催化剂对该粉体的微观形貌和负热膨胀性能的影响。结果表明:当加入的酸性催化剂为HCl和HNO_3时,能够获得结晶良好、纯度高的纳米ZrW_2O_8粉体,而以其他5种酸为催化剂均未能得到ZrW_2O_8粉体;以HCl为催化剂时,ZrW_2O_8粉体呈絮状团聚,以HNO_3为催化剂时则呈规则棒状;ZrW_2O_8粉体均表现出良好的负热膨胀性能,在相同的温度下,晶胞参数较小的其热膨胀系数较大。

Using HAc,HClO4 ,H2 SO4 ,H3 PO4 ,（NH4 ）2 HPO4 ,HCl and HNO3 as catalysts respectively, zirconium oxynitrate and ammonium metatungstate as raw materials,ZrW2 O8 powder was prepared by the sol-gel method.The effects of different acid catalysts on the micromorphology and negative thermal expansion property were analyzed.The results show that the well-crystallized and pure ZrW2 O8 powder was obtained when the added acid catalyst was HCl or HNO3 ,while no ZrW2 O8 powder was obtained with the other five kinds of acid catalysts. The ZrW2 O8 powder was flocculent aggregation using HCl catalyst while that was regular rod-like with HNO3 catalyst;the negative thermal expansion property of the ZrW2 O8 powder was strong and the heat expansion coefficient with a relatively small unit cell parameter was a relatively high at the same temperature.