煅烧条件对溶胶-凝胶法合成超细ZrB_(2)粉体的影响

Effect of Calcination Conditions on Synthesis of Ultrafine ZrB_(2) Powder by Sol-Gel Method

ZrB_(2)基陶瓷材料在超高温领域具有广阔的应用前景,为研究煅烧条件对ZrB_(2)粉体的影响,本研究分别以正丙醇锆、蔗糖和硼酸为Zr源、C源和B源,采用溶胶-凝胶法制备ZrB_(2)粉体,研究了煅烧温度、保温时间及氩气流量对ZrB_(2)粉体合成的影响。结果表明,随着煅烧温度的升高,生成物中的杂质相含量逐渐降低,ZrB_(2)相含量逐渐增加。B∶Zr∶C摩尔比为2.85∶1∶7的前驱体粉体在氩气气氛、1550℃下分别保温30、60和120 min后均得到了纯ZrB_(2)粉体。由Scherrer公式计算得到的ZrB_(2)平均晶粒尺寸远小于SEM观测的粒径,表明制得的ZrB_(2)粉体由小晶粒组成。煅烧过程中通入的氩气流量会影响B_(2)O_(3)的挥发程度,进而影响产物的物相组成。

ZrB_(2)-based ceramics have broad application prospects in the field of ultra-high temperature.ZrB_(2) powders are prepared by sol-gel method with zirconium propanol,sucrose and boric acid as Zr,C and B sources,respectively,and the effects of calcination temperature,holding time and argon flow rate on the synthesis of ZrB_(2) powder are studied.The results show that with the increase of calcination temperature,the content of impurity phase in the product decreases gradually,and that the content of ZrB_(2) phase increases gradually.Pure ZrB_(2) powders are obtained by holding the precursor powders with a molar ratio of 2.85∶1∶7 of B∶Zr∶C in argon atmosphere at 1550℃ for 30,60 and 120 minutes.The average grain size of ZrB_(2) powders calculated by Scherrer formula is much smaller than that observed by SEM,indicating that the ZrB_(2) powders are composed of small grains.The argon flow rate during calcination process will affect the volatilization degree of B_(2)O_(3),and then affect the phase composition of the product.