MgO-CaZrO_3-ZrO_2系含MgO复合陶瓷的结构与烧结性能

以烧结镁砂、单斜氧化锆和实验室预合成锆酸钙为原料,采用常压烧结法制备了MgO-CaZrO_3-ZrO_2系含MgO复合陶瓷,研究了ZrO_2含量、CaZrO_3含量及CaZrO_3/ZrO_2质量比对其复合陶瓷结构与烧结性能的影响。结果表明:高温下Zr⁴⁺、Ca²⁺、Mg²⁺离子的扩散、c-ZrO_2(Zr_(0. 875)Mg_(0. 125)O_(1. 875)或Zr_(0. 8)Mg_(0. 2)O_(1. 8))的形成及CaZrO_3脱CaO分解等,是影响MgO-CaZrO_3-ZrO_2系含MgO复合陶瓷结构与烧结性能的重要因素;其中MgO-ZrO_2复合陶瓷的断裂方式为穿晶断裂,MgO-CaZrO3复合陶瓷和MgO-CaZrO_3-ZrO_2复合陶瓷的断裂方式为以沿晶断裂为主的混合断裂,其复合陶瓷的烧结强度依次降低;当ZrO_2含量为20wt%～40wt%、CaZrO_3含量为10wt%～40wt%及CaZrO_3/ZrO_2质量比为6/1～5/2时可分别制得烧结性能较好的MgO-ZrO_2、MgO-CaZrO3和MgO-CaZrO_3-ZrO_2复相陶瓷。

Microstructure and Sintering Properties of MgO-CaZrO3-ZrO2 Series Composite Ceramics Containing MgO

Using sintered magnesite, monoclinic zirconia and pre-synthesis calcium zirconate as raw materials and using atmospheric pressure sintering method, MgO-CaZrO 3-ZrO 2 series composite ceramics containing MgO were prepared. And the effects of the dosage of CaZrO 3, the dosage of ZrO 2 and the mass ratio of CaZrO 3/ZrO 2 on the microstructure and sintering properties of composite ceramics were studied. The results show that at high temperature the ion diffusion of Zr^4+, Ca 2+ and Mg 2+, the formation of c-ZrO 2(Zr 0.875 Mg 0.125 O 1.875 or Zr 0.8 Mg 0.2 O 1.8 ) and the decomposition of CaZrO 3 because of the detachment of CaO were the important factors influencing the microstructure and sintering properties of MgO-CaZrO 3-ZrO 2 series composite ceramics containing MgO. The fracture mode of MgO-ZrO 2 ceramic was transgranular fracture, and the fracture mode of MgO-CaZrO 3 ceramic and MgO-CaZrO 3-ZrO 2 ceramic was a mixed fracture dominated by intergranular fracture. The sintering strength of composite ceramics decreased in turn. When the dosage of ZrO 2 was 20wt%-40wt%, the dosage of CaZrO 3 was 10wt%-40wt% and the mass ratio of CaZrO 3/ZrO 2 was 6/1-5/2, MgO-ZrO 2 ceramic, MgO-CaZrO 3 ceramic and MgO-CaZrO 3-ZrO 2 ceramic with good sintering properties were obtained, respectively.