Abstract:Using α-Si3N4 as raw powder and MgO-Y2O3-Re2O3 as sintering assistant, Si3N4 ceramics were prepared by hot-pressing sintering, and the density, phase composition, microstructure, thermal conductivity, bending strength and fracture toughness of Si3N4 were tested by archimedean drainage method, XRD, SEM, laser flash method, three-point bending method and indentation method. Studies show that in samples with MgO-Y2O3-Re2O3 (Re=Er, Sm, Dy, La, Y, Yb) added, Sm2O3 , Y2O3 ,Yb2O3 are easy to facilitate Y2O3 to form the second phase Y2SiO3 , Y2Si3O3N4 and Y2SiO5 , respectively. Meanwhile, in the Si3N4 with MgO-Y2O3-Re2O3 (Re=Sm, Dy, La,Yb) added, the long columnar crystals are uniformly embedded in the smaller matrix grains, with self-strengthening and toughening. The bending strength is above 920 MPa, and the fracture toughness of indentation is above 6.93 MPa∙m1/2. Compared with traditional binary sintering assistant MgO-Re2O3, MgO-Y2O3-Re2O3 ternary additive has no regular influence on the microstructure, bending strength and fracture toughness of Si3N4 ceramics with the change of Re3+ radius, but its thermal conductivity increases with the decrease of Re3+ radius.
鲁欣欣, 刘伟, 李林, 李建斌. MgO-Y2O3-Re2O3添加对氮化硅陶瓷微观组织及性能的影响[J]. 粉末冶金材料科学与工程, 2019, 24(6): 536-541.
LU Xinxin, LIU Wei, LI Lin, LI Jianbin. Effects of MgO-Y2O3-Re2O3 on microstructure and properties of Si3N4 ceramics. Materials Science and Engineering of Powder Metallurgy, 2019, 24(6): 536-541.
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