Wear behaviour and electrical conductivity of β-Sialon-ZrN composites fabricated by reaction bonding and gas pressure sintering process

2019 ◽  
Vol 45 (2) ◽  
pp. 2266-2274 ◽  
Author(s):  
Li Yin ◽  
Wei Gao ◽  
Mark Ian Jones
Keyword(s):  
Electrical Conductivity ◽  
Gas Pressure ◽  
Wear Behaviour ◽  
Sintering Process ◽  
Reaction Bonding ◽  
Gas Pressure Sintering

Influence of YAG-Based Composite Sintering Aids on Gas Pressure Sintered BNw/Si3N4 Composites

2015 ◽  
Vol 655 ◽  
pp. 53-57
Author(s):  
Xian Li Wang ◽  
Hong Yu Gong ◽  
Yu Jun Zhang ◽  
Song Wei Che
Keyword(s):  
Dielectric Properties ◽  
Bending Strength ◽  
Mechanical Performance ◽  
Raw Materials ◽  
Gas Pressure ◽  
Apparent Porosity ◽  
Sintering Process ◽  
Sintering Aids ◽  
Liquid Phases ◽  
Gas Pressure Sintering

BNw/Si3N4composites were fabricated by gas pressure sintering process using α-Si3N4powder and self-made BN whisker as principal raw materials. The effects of different sintering additives such as YAG, MgO+YAG and RE2O3+YAG(RE=La, Sm, Dy) on the apparent porosity, microstructure, phase composition, mechanical performance and dielectric properties of the composites were analysed. The results revealed that composite sintering aids at certain ratio (MgO/RE2O3:YAG=1:5) was more conducive to ceramic densification than single YAG additive. The BNw/Si3N4sintered with La2O3+YAG acquired the highest density and the maximum bending strength (272.46 MPa) and fracture toughness(4.9 MPa·m1/2). It was speculated that ceramic densification process was related to formation of different eutectic liquid phases with different viscosity. Additionally, when the apparent porosity of BNw/Si3N4composites was 20% or less, dielectric properties of the material were mainly influenced by the porosity and the value of the permittivity and dielectric loss decreased with the increase of ceramic porosity.

Defects Analysis of Large Size Silicon Nitride Balls Sintered by Gas Pressure Sintering

2010 ◽  
Vol 434-435 ◽  
pp. 61-63
Author(s):  
Feng Sun ◽  
Wei Ru Zhang ◽  
Ting Yan Tian ◽  
Xiang Hong Teng ◽  
Min Chao Ru ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Silicon Nitride ◽  
Temperature Gradient ◽  
Raw Materials ◽  
Gas Pressure ◽  
Sintering Process ◽  
The Core ◽  
Large Size ◽  
Defects Analysis ◽  
Gas Pressure Sintering

The sections of Φ55mm silicon nitride balls, sintered by gas pressure sintering were analyzed. The results show that temperature gradient during of the sintering process from the surface to the core of large size silicon nitride balls occurred because of the lower thermal conductivity of Si3N4. With the diameter increasing, the temperature gradient was more visible. The impurity of raw materials, such as free Si, free C and other metal oxides, like the SiO2 could produce gas, such as SiO, CO and so on, during the sintering process through the thermodynamic analysis. The producing gas exhausted more difficultly with the diameter of silicon nitride balls increasing. These factors were the most important to the defects of large size silicon nitride balls during the sintering process and made cracks and crescent on the surface of balls.

Sign in / Sign up

Export Citation Format

Share Document