稀土对Si_3N_4陶瓷力学性能和显微组织的影响

Effect of Rare Earths on Mechanical Properties and Microstructure of Si_3N_4 Ceramic

研究了Y2 O3,La2 O3,Nd2 O3等稀土氧化物对Si3N4 陶瓷力学性能和显微组织的影响。添加稀土氧化物的Si3N4 陶瓷可以获得较好的力学性能。添加复合稀土氧化物 (Y2 O3+La2 O3)后 ,断裂韧性达 7 8MPa·m1 2 ,抗弯强度达 962MPa,其性能提高的主要原因是稀土氧化物改善了材料的显微组织 ,提高了 β Si3N4 晶粒的长径比。

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.