High‐performance alumina composite ceramics with brick‐and‐mortar structure derived from microsphere

• DOI: 10.1002/ces2.70002
• Publication Date: 2025-03-16T14:35:46Z
• Authors: Yedong Rong; Shihui Zhao; Qifan Zhang; Jianli Qiao; Guolong Sang; Xiaoqing Xi; Jinlong Yang

AbstractA series of alumina composite ceramics with a brick‐and‐mortar structure were successfully prepared by coating with different contents of ZrO2 and alumina sol on Al2O3 microspheres and hot pressing. By changing the process parameters, the influence of hot pressing on the mechanical properties of the material was explored. The synergistic effect of brick‐and‐mortar structure toughening, phase transformation toughening, and alumina sol self‐toughening improves the mechanical properties of the alumina composite ceramics. The samples coated with ZrO2 and alumina sol achieved the best performance when hot pressing pressure is 30 MPa and the temperature is 1540°C, with a fracture toughness of 7.4 MPa·m1/2 and a flexural strength of 671 MPa. The ZrO2 content of this sample is only 2 wt%. Compared with the control group of Al2O3 solid microspheres directly hot pressed, the fracture toughness increased by 17% and 26%, respectively. Self‐toughening Al2O3 ceramics were successfully prepared by coating alumina sol. Its fracture toughness is 6.8 MPa·m1/2 and its flexural strength is 600 MPa. This method is not only suitable for toughening alumina composite ceramics, but also maintains their high strength, with the potential for industrial production.