感应区熔法制备Al_2O_3/MgAl_2O_4/ZrO_2共晶陶瓷

Preparation of Al_2O_3/MgAl_2O_4/ZrO_2 Eutectic Ceramic by Induction Zone Melting Method

利用感应区熔法制备了Al2O3/MgAl2O4/ZrO2共晶陶瓷。当坩埚壁温为2200℃、行走速度为2 mm/h时,制备了10 mm×62 mm表面光滑致密的陶瓷样品。扫描电镜微观组织图显示Al2O3相和MgAl2O4相为基体相,ZrO2相以棒状镶嵌在基体中。定向凝固共晶陶瓷硬度和断裂韧性达到12 GPa和6.1 MPa·m1/2,为预烧结体的2倍和1.7倍。气孔和晶界的消失及细小规整ZrO2相在基体中的弥散分布,有效提高了材料的硬度和断裂韧性。

Al2O3/MgAl2O4/ZrO2 eutectic ceramic was prepared with induction zone melting （ZM） method. When the crucible wall temperature is 2200 ℃, and the crucible rate is 2 mm/h, a dense rod sample was prepared with smooth surface. Its microstructure reveals that the Al2O：MgAl2O4 phase is the matrix, and the ZrO2 stick sets in the matrix. Its hardness reaches 12 GPa, which is about two times of the sintered sample. Its fracture toughness at temperature reaches 6.1 MPa·m^1/2, which is about 1.7 times of the sintered sample. The disappearance of the grain boundaries and pores, and the dispersion of the fine ZrO2 phases with round shape in the matrix result in the improvement of the materialg hardness and fracture toughness.