锆英石碳热还原制备ZrB2-ZrO2-SiC复合粉体

以锆英石、硼酸和炭黑为原料，在流通氩气气氛中于1 500℃煅烧制备ZrB₂-ZrO₂-SiC复合粉体，研究了保温时间（分别为3、6和9 h）和添加剂AlF₃添加量（质量分数分别为0、0.5%、1.0%、1.5%、2.0%和2.5%）对合成产物物相组成和显微结构的影响。结果表明：1)将锆英石在流通氩气气氛中于1 500℃碳热还原可制备ZrB₂-ZrO₂-SiC复合粉体；ZrB₂、ZrO₂呈粒状，SiC呈纤维状。2)随着保温时间的延长，ZrB₂的量逐渐增多，m-ZrO₂和SiC的量均逐渐减少，非氧化物ZrB₂、SiC、ZrC的总量逐渐增多。3)与未添加AlF₃的试样相比，添加0.5%（w）AlF₃的试样中m-ZrO₂量显著减少，ZrB₂的量显著增多，SiC的量有所减少；但随着AlF

Preparation of ZrB2-ZrO2-SiC composite powder using zircon by carbothermal reduction method

Using zircon,boric acid and carbon black as starting materials,ZrB₂-ZrO₂-SiC composite powder was synthesized by calcining at 1500℃in flowing argon atmosphere.The effects of the soaking time(3,6 and 9 h)and the addition of additive AlF₃(0,0.5%,1.0%,1.5%,2.0%and 2.5%,by mass)on the phase composition and the microstructure of the synthesized products were investigated.The results show that:(1)ZrB₂-ZrO₂-SiC composite powder can be synthesized by carbothermal reduction at 1500℃in flowing argon atmosphere;ZrB₂ and ZrO₂ are granular-like,and SiC crystals are fiberous;(2)with the soaking time increasing,the amount of ZrB₂ increases,the amounts of m-ZrO₂ and SiC decrease,and the total amount of non-oxides ZrB₂,SiC and ZrC gradually increases;(3)compared with the specimen without AlF₃,the specimen with 0.5%AlF₃ has decreased m-ZrO₂ amount,noticeably increased ZrB₂ amount but decreased SiC amount;however,when the amount of AlF₃ increases from 0.5%to 2.5%,the m-ZrO₂ amount increases,the ZrB₂ amount decreases,and the SiC amount changes slightly;the optimum AlF₃ addition is 0.5%.