Effect of Rare Earths on Mechanical Properties and Microstructure of Si_3N_4 Ceramic
MU Bai chun 1, LI Ming 2, YOU Xiang qun 1, LIU Bing yu 1, GU Zhi gang 2, LIU Da wei 3 ( 1. Department of Material Engineering, Liaoning Institute of Technology, Jinzhou 121001, China; 2. Television University of Jinzhou Railway Bureau, Jinzho
The effects of Y 2O 3, La 2O 3 and Nd 2O 3 on the mechanical properties and microstructure of Si 3N 4 ceramics were studied. The experimental results show that the mechanical properties can be improved by adding rare earth in Si 3N 4. When Y 2O 3 and La 2O 3 are both added, fracture toughness and flexural strength 7 8 MPa·m 1/2 and 962 MPa respeolively. The reason is that the rare earths added in Si 3N 4 can improve the microstructure and increase the aspect ratio of crystal grains.