水热共还原法制备La_2O_3掺杂W-Cu复合粉末工艺研究

La_2O_3 Doped W-Cu Composite Powder Prepared by Hydrothermal-Coreduction Method

以水热合成法为基础,制备了La2O3掺杂量为2.0%(质量分数)的W-20Cu复合粉体,并通过SEM,HRTEM,DTA/TG及XRD等手段对复合粉体的物相、形貌和微观结构进行了表征。结果表明:水热共沉淀法制备稀土La2O3掺杂W-Cu复合粉时,对应前驱溶液的最佳p H为5.5。与不加稀土相比,水热产物分解温度降低,470℃煅烧2 h后,La与W形成复合氧化物La2W3O12,且分解形成的WO3相依附La(OH)3生长,其结晶性提高。在推杆式还原炉850℃于H2介质中还原2 h后,煅烧粉完全被转化为W,Cu和La2O3,HRTEM表征发现La2O3吸附在W和Cu颗粒的表面,阻止晶粒的长大,有望提高还原粉体的烧结性能。

This research was based on the hydrothermal synthesis process to prepare the 2. 0%（ mass fraction）La2O3doped W-20 Cu composite powders,and the phase,morphology and microstructure of composite powders were characterized through SEM,HRTEM,DTA / TG and XRD method. The results showed that the corresponding optimal p H of the precursor solution was 5. 5. The decomposition temperature of hydrothermal products was lower than the hydrothermal products with no rare earths. After annealing at 470 ℃ for 2 h,La and W would form the oxide in La2W3O12,and WO3 could grow attached to La（ OH）3,which will improve the crystalline. After reduced at850 ℃ for 2 h,the mixture calcined powders were converted into W,Cu and La2O3 phases completely,and the La2O3 adsorped on the surface of W-Cu particles could be found by HRTEM,so as to prevent the growth up of grains,and will greatly improve the sinter ability.