摘要
Porous SiO2-Si3N4 composite ceramics with high porosity and excellent mechanical properties were fabricated by pressureless-sintering at relatively low temperature of 1 500 ~C using diatomite as pore forming agent. The effects of diatomite on flexural strength, fracture toughness, shrinkage, porosity and phase transformation of the porous ceramics were investigated in detail. Compared with that of the ceramic without adding diatomite, the porosity of the ceramic with 10% diatomite is increased by about 27.4%, the flexural strength and fracture toughness reaches 78.04 MPa and 1.25 MPa.m1/2, respectively. As the porosity increases, the dielectric constant of porous SiO2-Si3N4 ceramic decreases obviously from 3.65 to 2.95.
Porous SiO2-Si3N4 composite ceramics with high porosity and excellent mechanical properties were fabricated by pressureless-sintering at relatively low temperature of 1 500 ~C using diatomite as pore forming agent. The effects of diatomite on flexural strength, fracture toughness, shrinkage, porosity and phase transformation of the porous ceramics were investigated in detail. Compared with that of the ceramic without adding diatomite, the porosity of the ceramic with 10% diatomite is increased by about 27.4%, the flexural strength and fracture toughness reaches 78.04 MPa and 1.25 MPa.m1/2, respectively. As the porosity increases, the dielectric constant of porous SiO2-Si3N4 ceramic decreases obviously from 3.65 to 2.95.
基金
Supported by the National Natural Science Foundation of China(No.51272132)
Independent Innovation Foundation of Shandong University(No.2012TS213)
State Key Laboratory of New Ceramic and Fine Processing,Tsinghua University(No.KF201403)
