Effect of nano-sized sintering additives on microstructure and mechanical properties of Si3N4 ceramics

2019 ◽  
Vol 750 ◽  
pp. 132-140 ◽  
Author(s):  
Anil Kumar ◽  
Aditya Gokhale ◽  
Sudarsan Ghosh ◽  
Sivanandam Aravindan
Keyword(s):  
Mechanical Properties ◽  
Sintering Additives ◽  
Microstructure And Mechanical Properties ◽  
Si3n4 Ceramics

Effects of Sintering Additives on the Microstructure and Mechanical Properties of Silicon Nitride Ceramics by GPS

2010 ◽  
Vol 105-106 ◽  
pp. 27-30 ◽  
Author(s):  
Wei Ru Zhang ◽  
Feng Sun ◽  
Ting Yan Tian ◽  
Xiang Hong Teng ◽  
Min Chao Ru ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Transformation ◽  
Silicon Nitride ◽  
Porous Silicon ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Additives ◽  
Microstructure And Mechanical Properties ◽  
Nitride Ceramics

Silicon nitride ceramics were prepared by gas pressure sintering (GPS) with different sintering additives, including La2O3, Sm2O3 and Al2O3. Effect of sintering additives on the phase-transformation, microstructure and mechanical properties of porous silicon nitride ceramics was investigated. The results show that the reaction of sintering additives each other and with SiO2 had key effects on the phase-transformation, grain growing and grain boundaries. With 9MPa N2 atmosphere pressure, holding 1h at 1850°C, adding 10wt% one of the La2O3, Sm2O3, Al2O3, porous silicon nitride was prepared and the relative density was 78%, 72%, 85% respectively. The flexural strength was less than 500MPa, and the fracture toughness was less than 4.8MPam1/2. Dropping compounds sintering additives, such as La2O3+Al2O3, Sm2O3+Al2O3 effectively improves the sintering and mechanical properties. The relative density was 99.2% and 98.7% with 10wt% compounds sintering additives. The grain ratio of length to diameter was up to 1:8. The flexural strength was more than 900MPa, and the fracture toughness was more than 8.9MPam1/2.

scholarly journals Effect of particle size of Y2O3-Al2O3 additives on microstructure and mechanical properties of Si3N4 ceramic balls for bearing applications

2021 ◽  
Vol 15 (3) ◽  
pp. 297-305
Author(s):  
Jing Zhang ◽  
Wenxue Wang ◽  
Feng Sun ◽  
Weiru Zhang ◽  
Boheng Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Relative Density ◽  
Si3n4 Ceramic ◽  
Sintering Additives ◽  
Microstructure And Mechanical Properties ◽  
Indentation Fracture Toughness ◽  
Effect Of Particle Size ◽  
Gas Pressure Sintering ◽  
Si3n4 Matrix

Si3N4 ceramic balls were prepared by gas pressure sintering with Y2O3 and Al2O3 as sintering additives. The effects of particle size of Y2O3-Al2O3 additives on densification, microstructure and mechanical properties of Si3N4 ceramic balls were investigated. The reliability of Si3N4 ceramic balls was evaluated through the Weibull modulus. The results showed that Si3N4 ceramic balls containing nanosized Y2O3-Al2O3 additives have a higher relative density and better comprehensivemechanical properties compared with the samples containing microsized additives, with relative density of 98.9 ? 0.2%TD, Vickers hardness of 14.7 ? 0.1GPa, indentation fracture toughness of 6.5 ? 0.1MPa?m1/2 and crushing strength of 254 ? 8.5MPa. The more homogeneous and extensive dispersion of the nanosized sintering additives in the Si3N4 matrix is the main reason for the enhancement in density and mechanical properties of the Si3N4 ceramic balls.

Microstructure and Mechanical Properties of Heat-Resistant Silicon Carbide Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 1409-1413 ◽  
Author(s):  
Young Wook Kim ◽  
Yong Seong Chun ◽  
Sung Hee Lee ◽  
Ji Yeon Park ◽  
Toshiyuki Nishimura ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Carbide ◽  
Intergranular Phase ◽  
Sintering Additives ◽  
Heat Resistant ◽  
Sic Ceramics ◽  
Microstructure And Mechanical Properties ◽  
Carbide Ceramics ◽  
Silicon Carbide Ceramics

There has been a great progress in the development of heat-resistant silicon carbide ceramics, owing to the better understanding of composition-microstructure-properties relations. Based on the progress, it has been possible to fabricate heat-resistant SiC ceramics with improved fracture toughness. In this paper, three rare-earth oxides (Re2O3, Re=Er, Lu, and Sc) in combination with AlN were used as sintering additives for a β-SiC containing 1 vol% α-SiC seeds. The effect of intergranular phase, using Re2O3 and AlN as sintering additives, on the microstructure and mechanical properties of liquid-phasesintered, and subsequently annealed SiC ceramics were investigated. The microstructure and mechanical properties were strongly influenced by the sintering additive composition, which determines the chemistry and structure of IGP. The strength and fracture toughness of the Lu2O3-doped SiC were ∼700 MPa at 1400oC and ∼6 MPa.m1/2 at room temperature, respectively. The beneficial effect of the new additive compositions on high-temperature strength was attributed to the crystallization of the intergranular phase.

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