Wear Property of Superfine Grained Si2N2O-Si3N4 Composites

2008 ◽  
Vol 368-372 ◽  
pp. 917-919
Author(s):  
Jun Ting Luo ◽  
Qing Zhang ◽  
Hong Bo Li
Keyword(s):  
Grain Size ◽  
Wear Resistance ◽  
Silicon Nitride ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
High Hardness ◽  
Liquid Phase Sintering ◽  
Wear Property ◽  
Average Grain Size ◽  
Bearing Ball

Si3N4-Si2N2O composites were fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering. The mass loss, relative density and average grain size increase with increasing sintering temperature. The average grain size is less than 500nm when the sintering temperature is lower than 1700°C. Friction coefficient is from 0.35 for sintering temperature 1650°C to 0.74 for 1600°C when the composites were worn by silicon nitride bearing ball. High hardness of 21.5GPa and relative wear resistance of 32 were observed at a sintering temperature of 1600°C. The wear surface are very smooth and no grooving and subsurface fracture, which indicates that they are worn slightly.

Liquid Phase Sintering Behavior of Amorphous Nano-Sized Silicon Nitride Powders

2007 ◽  
Vol 336-338 ◽  
pp. 1069-1071 ◽  
Author(s):  
H.B. Li ◽  
Jun Ting Luo ◽  
Kai Feng Zhang
Keyword(s):  
Grain Size ◽  
Silicon Nitride ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Sintering Behavior ◽  
Average Grain Size ◽  
Sintering Method ◽  
Amorphous Si3n4

The amorphous nano-sized silicon nitride powders were sintered by liquid phase sintering method. Si3N4-Si2N2O composites were in-situ fabricated. 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 obtained at a sintering temperature of 1650°C and reduced when the sintering temperature increased or decreased, which indicates that the reaction is reversible. The mass loss, relative density and average grain size increase with increasing of sintering temperature. The average grain size is less than 500nm when the sintering temperature is below 1700°C. During the sintering procedure, there is a complex crystallization and phase transition: amorphous Si3N4 → equiaxial α-Si3N4→ equiaxial β-Si3N4 → rod-likeSi2N2O → needle-like β-Si3N4. Small round-shaped β-Si3N4 particles are entrapped in the Si2N2O grains and a high density of staking faults are situated in the middle of Si2N2O grains at a sintering temperature of 1650°C.

Low temperature sintering of nano-SiC using a novel Al8B4C7 additive

2010 ◽  
Vol 25 (3) ◽  
pp. 471-475 ◽  
Author(s):  
Sea-Hoon Lee ◽  
Byung-Nam Kim ◽  
Hidehiko Tanaka
Keyword(s):  
Grain Size ◽  
Liquid Phase ◽  
Low Temperature ◽  
Sintering Temperature ◽  
Applied Pressure ◽  
Liquid Phase Sintering ◽  
Low Temperature Sintering ◽  
Densification Rate ◽  
Sintering Additive ◽  
Average Grain Size

Al8B4C7 was used as a sintering additive for the densification of nano-SiC powder. The average grain size was approximately 70 nm after sintering SiC-12.5wt% Al8B4C7 at 1550 °C. The densification rate strongly depended on the sintering temperature and the applied pressure. The rearrangement of SiC particles occurred at the initial shrinkage, while viscous flow and liquid phase sintering became important at the middle and final stage of densification.

Synthesis of WC-10wt.%Co Nanocrystalline Powders with Grain Growth Inhibitor by MTP

2007 ◽  
Vol 534-536 ◽  
pp. 1237-1240 ◽  
Author(s):  
Dong Kyu Park ◽  
Kwang Chul Jung ◽  
Jin Chun Kim ◽  
Sung Yeal Bae ◽  
In Sup Ahn
Keyword(s):  
Grain Size ◽  
Wear Resistance ◽  
Liquid Phase ◽  
Grain Growth ◽  
Growth Inhibitor ◽  
Liquid Phase Sintering ◽  
Nanocrystalline Powders ◽  
Grain Growth Inhibitor ◽  
Nano Crystalline ◽  
Carburizing Process

To improve the fracture strength and wear resistance of WC-Co cemented carbide, various technologies have been developed related producing the nano crystalline. There have been extensive studied conducted to retard grain growth during liquid phase sintering. However, when this inhibitor is added by simple mixing, a micro-pores forms during sintering In this study, WC-Co nanocrystalline powders with grain growth inhibitor in the site were prepared by MTP (Mechano-Thermic carburizing Process) to minimize this formation of micro pores and to retard grain growth effectively during sintering. In addition, then the phase and grain size of WC-Co nanocrystalline powders were evaluated according to the condition of MTP.

Superplastic Sinter-Forging of Fine-Grained Si3N4-Si2N2O Composite at Low Temperature

2007 ◽  
Vol 551-552 ◽  
pp. 487-490 ◽  
Author(s):  
Jun Ting Luo ◽  
Qing Zhang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Complex Shape ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
Liquid Phase Sintering ◽  
Sintered Body ◽  
Fine Grained ◽  
Sinter Forging ◽  
Average Grain Size

The Si3N4- Si2N2O composites are fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering (LPS) method. XRD analysis shows sintered body consists of β-Si3N4 and Si2N2O. SEM experiment conforms that the average grain size of sintered body is less than 300nm. The complex-shape gears can be formed by a sinter-forging technology when the sintering temperature is 1600°C and the superplastic forging temperature is only 1550°C. Rod-shaped grains aligned along the perpendicular direction of pressure and the mechanical properties increase about 10% after the materials were forged.

Superplasticity and Sinter-Forging of Fine-Grained Si3N4-Si2N2O Composite

2005 ◽  
Vol 475-479 ◽  
pp. 2987-2990 ◽  
Author(s):  
Jun Ting Luo ◽  
Kai Feng Zhang ◽  
Guo Feng Wang ◽  
Wen Bo Han
Keyword(s):  
Grain Size ◽  
Complex Shape ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
Liquid Phase Sintering ◽  
Sintered Body ◽  
Fine Grained ◽  
Sinter Forging ◽  
Average Grain Size ◽  
Cavitation Failure

The Si3N4- Si2N2O composites are fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering(LPS) method in this article. XRD analysis shows that the sintered body consists of β-Si3N4 and Si2N2O. SEM experiment conforms that the average grain size of sintered body is less than 300nm. The superplastic deep-drawing forming can be proceed at a low temperature of 1550°C with a forming velocity of 0.2mm/min. There are only a few small sintered defects before forming, but there are a lot of cavity groups after forming. Cavitation failure occurs by nucleation, growth and interlinkage of cavities. The complex-shape gears can be formed by a sinter-forging technology when the sintering temperature is 1600°C and the superplastic forging temperature is 1550°C.

Role of pO2 in microstructural development and properties of YBa2Cu3Ox superconductors

1992 ◽  
Vol 7 (9) ◽  
pp. 2324-2332 ◽  
Author(s):  
J.P. Singh ◽  
R.A. Guttschow ◽  
J.T. Dusek ◽  
R.B. Poeppel
Keyword(s):  
Activation Energy ◽  
Grain Size ◽  
Liquid Phase ◽  
Liquid Phase Sintering ◽  
Microstructural Development ◽  
Sintering Behavior ◽  
Sintering Kinetics ◽  
Fine Grain ◽  
Average Grain Size

An evaluation of the effects of oxygen partial pressure (pO2) on sintering behavior and the resulting microstructure of YBa2Cu3Ox (YBCO) indicates that sintering kinetics are enhanced at reduced pO2. The density of specimens sintered at 910 °C increased from 79 to 94% theoretical when pO2 was decreased from 0.1 to 0.0001 MPa. It is believed that increase in density with decrease in pO2 is the result of enhanced sintering kinetics, due probably to increased defect concentration, decreased activation energy of the rate-controlling species, and possibly the presence of a small amount of liquid phase. Sintering at 910 °C resulted in a fine-grain microstructure, with an average grain size of ≍4 μm. Such a microstructure results in reduced microcracking. Consequently, strength as high as 191 MPa is achieved. Reduced microcracking may have important implications for developing microstructures with improved critical current density.

Electron Microscopy of Silicon Nitride-Based Ceramics

1991 ◽  
Vol 49 ◽  
pp. 926-927
Author(s):  
Gareth Thomas
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Silicon Nitride ◽  
World Wide ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
High Temperature Strength ◽  
Sintering Additives ◽  
Glass Forming ◽  
Dense Product

Silicon nitride and silicon nitride based-ceramics are now well known for their potential as hightemperature structural materials, e.g. in engines. However, as is the case for many ceramics, in order to produce a dense product, sintering additives are utilized which allow liquid-phase sintering to occur; but upon cooling from the sintering temperature residual intergranular phases are formed which can be deleterious to high-temperature strength and oxidation resistance, especially if these phases are nonviscous glasses. Many oxide sintering additives have been utilized in processing attempts world-wide to produce dense creep resistant components using Si3N4 but the problem of controlling intergranular phases requires an understanding of the glass forming and subsequent glass-crystalline transformations that can occur at the grain boundaries.

scholarly journals Synthesis and Na+ Ion Conductivity of Stoichiometric Na3Zr2Si2PO12 by Liquid-Phase Sintering with NaPO3 Glass

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3790
Author(s):  
Yongzheng Ji ◽  
Tsuyoshi Honma ◽  
Takayuki Komatsu
Keyword(s):  
Solid State ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Ion Conductivity ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Sintering Time ◽  
Lower Activation

Sodium super ionic conductor (NASICON)-type Na3Zr2Si2PO12 (NZSP) with the advantages of the high ionic conductivity, stability and safety is one of the most famous solid-state electrolytes. NZSP, however, requires the high sintering temperature about 1200 °C and long sintering time in the conventional solid-state reaction (SSR) method. In this study, the liquid-phase sintering (LPS) method was applied to synthesize NZSP with the use of NaPO3 glass with a low glass transition temperature of 292 °C. The formation of NZSP was confirmed by X-ray diffraction analyses in the samples obtained by the LPS method for the mixture of Na2ZrSi2O7, ZrO2, and NaPO3 glass. The sample sintered at 1000 °C for 10 h exhibited a higher Na+ ion conductivity of 1.81 mS/cm at 100 °C and a lower activation energy of 0.18 eV compared with the samples prepared by the SSR method. It is proposed that a new LPE method is effective for the synthesis of NZSP and the NaPO3 glass has a great contribution to the Na+ diffusion at the grain boundaries.

Recrystallization of Oxygen Contaminated Al Films

1986 ◽  
Vol 71 ◽  
Author(s):  
G.J. Van Der Kolk ◽  
M.J. Verkerk
Keyword(s):  
Grain Size ◽  
Silicon Nitride ◽  
Substrate Temperature ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Relative Increase ◽  
Partial Pressures ◽  
Average Grain Size

AbstractAl was evaporated at oxygen partial pressures, PO2, varying between 10−7 and 10−4 Pa on substrates of silicon nitride. The substrate temperature was varied between 20 °C and 250°C. The films were annealed at temperatures up to 500°C.For Al films deposited at 20°C, it was found that the average grain size decreases with increasing oxygen partial pressure. After annealing recrystallization was observed. The relative increase of grain size was less for higher values of pO2. Annealing gave rise to a broad grain size distribution.For Al films deposited at 250°C, the presence of oxygen caused the growth of rough inhomogeneous films. This inhomogeneous structure remained during annealing.

Investigation of Isothermal Treatment on the Structural, Microstructure and Physical Properties of Li2O-Al2O3-SiO2 Glass-Ceramic

2020 ◽  
Author(s):  
Husniyah Aliyah Lutpi ◽  
Hasmaliza Mohamad ◽  
Tuti Katrina Abdullah
Keyword(s):  
Grain Size ◽  
Elevated Temperature ◽  
Physical Properties ◽  
Thermal Shock ◽  
Glass Ceramic ◽  
Crystalline Phase ◽  
Sintering Temperature ◽  
Isothermal Treatment ◽  
Crystalline Phases ◽  
Average Grain Size

Abstract The present work aims to investigate the effects of isothermal treatment on the structural, microstructure and physical properties of Li2O-Al2O3-SiO2 glass-ceramic. Sintering temperature plays a major role in producing the desired lithium aluminosilicate (LAS) glass-ceramic crystalline phases. This work also aims to achieve a low thermal expansion coefficient β-spodumene (LiAlSi2O6) crystalline phase with improved density and lower porosity, which can be useful for the applications with thermal shock properties. The LAS glass-ceramic was fabricated by the melt-quenching technique at 1550 °C for 5 h before being isothermally sintered at an elevated temperature of 900 to 1200 °C for 30 min. The evolution of LAS glass-ceramic crystalline phases was identified using differential thermal analysis and the β-spodumene exothermic peak appeared at 999 °C. Based on the X-ray diffraction results, the complete transformation of β-spodumene from high-quartz solid solution (β-quartz) occurred at 1000 °C. However, the sintering temperature did not change the crystalline phase when sintered above 1000 °C, but the lattice parameter of the crystal structure was slightly altered. Moreover, it was observed that the LAS glass-ceramic grain size increased with temperature, whereby the smallest average grain size recorded (0.61 µm) for LAS glass-ceramic sintered at 1100 °C. Meanwhile, the fully densified LAS glass-ceramic at 1100 ° C was measured at 2.47 g/cm3 with 0.52% porosity. The isothermal treatment at elevated temperature indicated that sintering at 1100 °C provided a denser, less porous, and small average grain size which is preferred for thermal shock resistance applications.

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