添加ZrO_2对Ta_2O_5陶瓷结构与性能的影响

EFFECT OF ZrO_2 ADDITIVE ON MICROSTRUCTURE AND PROPERTIES OF Ta_2O_5 CERAMIC

以ZrO2和Ta2O5粉体为原料,采用固相反应法制备了ZrO2掺杂Ta2O5陶瓷。研究了ZrO2掺杂对Ta2O5陶瓷的相组成、微观结构、抗弯强度、热膨胀系数和抗热震性能的影响。结果表明:ZrO2掺杂可在烧成过程中抑制β-Ta2O5相向α-Ta2O5相的转变,5%(质量分数,下同)ZrO2掺杂Ta2O5陶瓷为β-Ta2O5单相固溶体。3%ZrO2掺杂,显著抑制了Ta2O5陶瓷高温烧结过程中的晶粒长大,避免了晶界开裂;掺杂量达到5%以上时,可显著促进Ta2O5陶瓷的烧结致密化。5%ZrO2掺杂的Ta2O5陶瓷表现出较高的抗弯强度(74.5MPa),低的热膨胀系数(1.96×10-6/℃)和良好的抗热震性能。

Ta2O5 ceramics doped with ZrO2 were prepared through solid-state reaction using Ta2O5 and ZrO2 micro-powders as raw materials. The effects of ZrO2 addition on the properties of Ta2O5 ceramics,such as phase composition,microstructure,bending strength,thermal expansion coefficient and thermal shock resistance,were investigated. The results show that the phase transformation for Ta2O5 ceramic from the orthorhombic （β） phase to the tetragonal （α） phase is inhibited by the introduction of ZrO2,and the Ta2O5 ceramic with 5% in mass ZrO2 doping is composed of pure β-Ta2O5 solid solution. With the addition of 3% ZrO2,the grain growth of Ta2O5 ceramic during sintering can be inhibited,and the cracking along grain boundary can be obviously avoided. The densification of Ta2O5 ceramic can be greatly improved when the amount of ZrO2 doped is more than 5%. The 5% ZrO2 doped Ta2O5 ceramic has high bending strength （74.5 MPa）,a low thermal expansion coefficient（1.96 × 10-6/ ℃ ） and good thermal shock resistance.