溶剂热法结合熔盐辅助硼碳热还原合成(Ti_(0.2)Mo_(0.2)W_(0.2)Ta_(0.2)Nb_(0.2))B_(2)粉体

Solvent Thermal Method Combined with Molten Salt Assisted Boron Carbon Thermal Reduction to Synthesize(Ti_(0.2)Mo_(0.2)W_(0.2)Ta_(0.2)Nb_(0.2))B_(2) Powder

以(Ti、Mo、W、Ta、Nb)过渡金属氯化物、乙醇、十六烷基三甲基溴化铵及氢氧化钠为原料,采用溶剂热法合成高熵前驱体,研究NaOH加入量对合成高熵前驱体的影响;随后,以TiMoWTaNb高熵前驱体和碳化硼为原料,采用溶剂热法结合熔盐辅助硼碳热还原工艺合成(Ti_(0.2)Mo_(0.2)W_(0.2)Ta_(0.2)Nb_(0.2))B_(2)粉体,分别研究了反应温度、保温时间及反应物用量对所合成粉体的物相组成和显微结构的影响。结果表明:当反应温度为1473 K、保温时间为3 h、NaOH的加入量为64 mmol,且TiMoWTaNb高熵前驱体与碳化硼(B_4C)摩尔比为1.0∶1.1、熔盐介质/反应物质量比为5.0∶1.0时,所制得样品为纯相,合成的单相(Ti_(0.2)Mo_(0.2)W_(0.2)Ta_(0.2)Nb_(0.2))B_(2)粉体中元素分布均匀。

High entropy precursors were first synthesized by using a solvothermal method with(Ti,Mo,W,Ta,Nb)transition metal chlorides,ethanol,cetyltrimethylammonium bromide and sodium hydroxide as raw materials,with the effect of NaOH to be studied.Subsequently,(Ti_(0.2)Mo_(0.2)W_(0.2)Ta_(0.2)Nb_(0.2))B_(2) powder was derived from the TiMoWTaNb high-entropy precursors and boron carbide by using a solvothermal method combined with a molten salt-assisted boron-carbon thermal reduction process.The effects of reaction temperature,holding time and reactant dosage on phase composition and microstructure of the powder were studied.When the reaction temperature is 1473 K,the holding time is 3 h,the content of NaOH is 64 mmol,niMowTanb:nB.c=1.0:1.1,and the salt-feed ratio is 5.0:1.0,the highest purity can be achieved.The single-phase(Ti_(0.2)Mo_(0.2)W_(0.2)Ta_(0.2)Nb_(0.2))B_(2) powder has a uniform element distribution.