Hot Press Sintering and Superplastic Forming of Fine-Grained Si3N4-Si2N2O Composites

2006 ◽  
pp. 25-28
Author(s):  
Qing Zhang ◽  
Jun Ting Luo ◽  
Kai Feng Zhang
Keyword(s):  
Superplastic Forming ◽  
Hot Press ◽  
Fine Grained ◽  
Hot Press Sintering

Hot Press Sintering and Superplastic Forming of Fine-Grained Si3N4-Si2N2O Composites

2006 ◽  
Vol 532-533 ◽  
pp. 25-28 ◽  
Author(s):  
Qing Zhang ◽  
Jun Ting Luo ◽  
Kai Feng Zhang
Keyword(s):  
Grain Size ◽  
Complex Shape ◽  
Sintering Temperature ◽  
Superplastic Forming ◽  
Hot Press ◽  
Fine Grained ◽  
Sinter Forging ◽  
Average Grain Size ◽  
Hot Press Sintering

Si3N4- Si2N2O composites were fabricated with amorphous nano-sized silicon nitride powders by the hot press sintering(HPS). The Si2N2O phase was generated by an in-situ reaction 2Si3N4(s)+1.5O2(g)=3Si2N2O(s)+N2(g). The content of Si2N2O phase up to 60% was accepted when the sintering temperature was 1650°C and decreased whether the sintering temperature was increased or not, which indicated that the reaction was reversible. The mass loss, relative density and average grain size increased with raising of sintering temperature. The average grain size was less than 500nm if the sintering temperature was below 1700°C. The sintered body crystaled completely at 1600°C . The microstructure crystaled in 1600°C indicated that most of the grain size was in 150-250nm. The aspect ratio of some grains reached 1.5. The superplastic deep-drawing forming could be undertaken at 1550°C with a forming velocity of 0.2mm/min. The complex-shape gears could be formed by a sinter-forging technology when the sintering temperature was 1600°C and the superplastic forging temperature was 1550°C.

Effect of Sintering Process on Microstructure of Al2O3/LiTaO3 Composite Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 2363-2365
Author(s):  
You Feng Zhang ◽  
Yu Zhou ◽  
De Chang Jia ◽  
Qing Chang Meng
Keyword(s):  
Grain Boundaries ◽  
Relative Density ◽  
Theoretical Density ◽  
Pressureless Sintering ◽  
Sintering Process ◽  
Hot Press ◽  
Composite Ceramics ◽  
Fine Grained ◽  
N2 Atmosphere ◽  
Hot Press Sintering

Effects of different sintering methods such as pressureless sintering and hot press sintering on relative density and microstructure of the Al2O3p/LiTaO3 (ALT) composite ceramics were investigated to obtain a preferable sintering process. Relative densities of all ALT composites are below 90% when sintered with the cold isostatical pressing followed by pressureless sintering at temperatures of 1250 to 1350°C. The relative densities and microstructure of ALT composite ceramics with the hot press sintering process in a N2 atmosphere at 1150 and 1300°C were investigated. The relative density of ALT composite hot pressed at 1150°C is only 77%, and almost theoretical density at 1300°C. This indicates that sintering pressure plays an important role in the densification of ALT composite ceramics in temperature range of 1150 to 1350°C. Investigation on morphologies of the composites shows that the Al2O3 particles distributed along grain boundaries of LiTaO3, which leads to a fine-grained microstructure in the ALT composite ceramics

A NOVEL LEAD-FREE TRANSPARENT CERAMIC WITH HIGH ELECTRO-OPTIC COEFFICIENT

2011 ◽  
Vol 04 (03) ◽  
pp. 237-240 ◽  
Author(s):  
K. W. KWOK ◽  
FALIANG LI ◽  
DUNMIN LIN
Keyword(s):  
Piezoelectric Properties ◽  
Optical Scattering ◽  
Lead Free ◽  
Relaxor Behavior ◽  
Hot Press ◽  
Pure Perovskite Structure ◽  
Fine Grained ◽  
Near Ir ◽  
Electro Optic ◽  
Hot Press Sintering

A novel lead-free transparent electro-optic ceramic (K0.5Na0.5)0.95 Li0.05Nb0.95Bi0.05O3+ 2 mol % excess Bi2O3 has been fabricated by hot-press sintering. The ceramic possesses a dense, fine-grained and pure-perovskite structure. Owing to the decreases in optical anisotropy of the crystal structure and optical scattering by the fine grains, the ceramic becomes visually clear. It exhibits a high transmittance of 60% in the near-IR region as well as a high effective linear electro-optic coefficient of 102 pm V-1. Although a relaxor behavior is induced, the ceramic exhibits reasonably good ferroelectric and piezoelectric properties (d33 = 64 pC N-1).

Toughness and Superplastic Deformation of Laminated Ceramic

2008 ◽  
Vol 368-372 ◽  
pp. 1799-1802
Author(s):  
Guo Feng Wang ◽  
Lin Liu ◽  
Hai Yang Wang ◽  
Kai Feng Zhang
Keyword(s):  
Superplastic Deformation ◽  
Tape Casting ◽  
Great Influence ◽  
Laminated Composite ◽  
Superplastic Forming ◽  
Hot Press ◽  
Deformation Properties ◽  
Prepared Material ◽  
Hot Press Sintering ◽  
Microstructure Of The Material

Tape casting and hot-press sintering were used to fabricate an Al2O3/3Y-TZP laminated composite. In order to investigate the deformation properties, the as-prepared material was deep drawn at high temperatures. It was found that the microstructure of the material sintered at 1550°C was fine and no significant pores were detected from SEM observations at the interfaces between the two types of layers. The superplastic forming experiment shown that, when the strain rate was constant, temperature had a great influence on the superplasticity of the Al2O3/3Y-TZP laminated composite. A hat-like part with the largest deformation height was obtained at 1500°C.

scholarly journals Remarkable plasma-resistance performance by nanocrystalline Y2O3·MgO composite ceramics for semiconductor industry applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hyeon-Myeong Oh ◽  
Young-Jo Park ◽  
Ha-Neul Kim ◽  
Kundan Kumar ◽  
Jae-Woong Ko ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Semiconductor Industry ◽  
High Plasma ◽  
Hot Press ◽  
Composite Ceramics ◽  
Plasma Resistance ◽  
Industry Applications ◽  
Hot Press Sintering ◽  
Resistance Performance ◽  
First Time

AbstractMotivated by recent finding of crystallographic-orientation-dependent etching behavior of sintered ceramics, the plasma resistance of nanocrystalline Y2O3-MgO composite ceramics (YM) was evaluated for the first time. We report a remarkably high plasma etching resistance of nanostructure YM surpassing the plasma resistance of commercially used transparent Y2O3 and MgAl2O4 ceramics. The pore-free YM ceramic with grain sizes of several hundred nm was fabricated by hot press sintering, enabling theoretical maximum densification at low temperature. The insoluble two components effectively suppressed the grain growth by mutual pinning. The engineering implication of the developed YM nanocomposite imparts enhanced mechanical reliability, better cost effectiveness with excellent plasma resistance property over their counterparts in plasma using semiconductor applications.

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