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.

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 and Microwave Dielectric Properties of CaWO4-Mg2SiO4 Ceramics

2014 ◽  
Vol 933 ◽  
pp. 12-16 ◽  
Author(s):  
Chung Long Pan ◽  
Ping Cheng Chen ◽  
Tsu Chung Tan ◽  
Wei Cheng Lin ◽  
Chun Hsu Shen ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Solid State ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Liquid Phase Sintering ◽  
Low Temperature Sintering ◽  
Sintering Aids ◽  
Sintering Aid ◽  
Microwave Dielectric

The effect of V2O5addition on the microstructures and the microwave dielectric properties of 0.9CaWO4-0.1Mg2SiO4(9CWMS) ceramics prepared by conventional solid-state routes have been investigated. The V2O5were selected as liquid phase sintering aids to lower the sintering temperature of 9CWMS ceramics. A small amount of V2O5(0.25~1 wt%) were used for sintering aid and led to high densification at 1050°C. The dielectric properties of 9CWMS ceramics with V2O5additions are strongly dependent on the densification, the microstructure. As the amount of V2O5additives increased from 0.25 to 1.0 wt%, the dielectric constantsεrdecreased following the trend with density. The quality valuesQdecreased with the increase of V2O5amount for all sintering temperatures. The 0.25 wt% V2O5-doped 0.9CaWO4-0.1Mg2SiO4ceramicssintered at 1080°C for 2 h had the optimum dielectric properties: εr= 5.7;Q×f= 73000 (at 14 GHz).

MgAl2O4 Transparent Nano-Ceramics Prepared by Sintering under Ultrahigh Pressure

2007 ◽  
Vol 280-283 ◽  
pp. 549-552 ◽  
Author(s):  
Xiang Hui Chang ◽  
Tie Cheng Lu ◽  
Ying Zhang ◽  
Xiang Jie Luo ◽  
Qiang Liu ◽  
...  
Keyword(s):  
Grain Size ◽  
Low Temperature ◽  
Sintering Temperature ◽  
Ultrahigh Pressure ◽  
Transparent Ceramics ◽  
Grain Sizes ◽  
Average Grain Size ◽  
Temperature And Pressure ◽  
Sintering Characteristics ◽  
Sintering Condition

The first experimental work to produce transparent MgAl2O4 nano-ceramics was reported in this paper. The sintering characteristics of transparent nano-ceramics were investigated at relatively low temperature (800 ~ 1100°C) under ultrahigh pressure (2 ~ 5 GPa) using hydrostatic equipment. The morphologies and phases of ceramics were observed by means of SEM and XRD, respectively. The grain sizes of the ceramics are shown to be less than one hundred nanometers, far smaller than the sizes of common transparent ceramics. Furthermore, the higher the sintering temperature and pressure are, the greater the extent of densification is. At the same temperature, the higher the pressure is, the smaller the average grain size is. Under the same pressure, the higher the temperature is, the larger the average grain size is. The optimal sintering condition for preparing transparent nano-ceramics was also determined.

Low Temperature Sintering of (Ba0.98Ca0.02)(Sn0.04Ti0.96)O3 Ceramics Using CuO-B2O3 as a Sintering Additive

2014 ◽  
Vol 602-603 ◽  
pp. 813-816
Author(s):  
Jian Qiang Zhou ◽  
Ke Pi Chen
Keyword(s):  
Low Temperature ◽  
Piezoelectric Properties ◽  
Sintering Temperature ◽  
Solid State Reaction Method ◽  
Low Temperature Sintering ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Sintering Additive ◽  
Precision Impedance Analyzer

The effects of CuO-B2O3(CBO) additive on densification, microstructure, and electrical properties of (Ba0.98Ca0.02)(Sn0.04Ti0.96)O3(BCST) cermaics were investigated. The phase compositions, microstructure, dielectric, ferroelectric and piezoelectric properties of BCST ceramics were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), precision impedance analyzer, ferroelectric tester and quasi-static piezoelectric constant testing meter, respectively. The results show that CuO-B2O3(CBO) frit can improve the densification and promote low-temperature sintering of BCST ceramics prepared by a conventional solid-state reaction method. Dense BCST ceramics with CBO can be sintered at temperatures as low as 1175 °C, which is approximately 275 °C less than the sintering temperature of pure BCST. When sintered at 1200 °C, the optimized properties of the BCST ceramics with 0.5 wt% CBO were obtain asε= 1206,d33= 346 pC/N,kP= 0.39, tgδ = 0.009.

Effect of Compound Additives of Li2O-B2O3-SiO2 Glass and LiF on the Properties of CaO-Li2O-Sm2O3-TiO2 Ceramics

2011 ◽  
Vol 284-286 ◽  
pp. 1349-1352
Author(s):  
Liu Shuan Yang ◽  
Xiao Wang ◽  
Yu Bin Wang ◽  
Jin Liang Huang ◽  
Fei Long Li
Keyword(s):  
Dielectric Properties ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Sintering Aids ◽  
Microstructure And Properties ◽  
Sintering Additive ◽  
Ceramic Samples

Using Li2O-B2O3-SiO2 (LBS) glass and LiF as a liquid phase sintering additive, the effects of it on the microstructure and properties of 16CaO-9Li2O-12Sm2O3-63TiO2（CLST）ceramics were investigated. The results indicated that the compound sintering aids of LBS glass and LiF reduced the sintering temperature of CLST from 1300 °C to 950°C. Compared with the sample doped single LBS glass, the optimum dielectric properties, Kr=81, Tanδ=0.0073 could be obtained when the CLST ceramic samples doped 3 wt% LBS glass and 0.25 wt% LiF were sintered at 950°C for 3 h.

Processing and Properties of Niobia-Doped Alumina Sintered at 1400oC

2014 ◽  
Vol 798-799 ◽  
pp. 665-670 ◽  
Author(s):  
Willian Trindade ◽  
Marcelo Henrique Prado da Silva ◽  
Alaelson Vieira Gomes ◽  
José Brant de Campos ◽  
Luis Henrique Leme Louro
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Elastic Constants ◽  
Dwell Time ◽  
Sintering Temperature ◽  
X Rays ◽  
Sintering Additive ◽  
Average Grain Size ◽  
Scanning Electron

Niobia is used as a sintering additive in alumina processing because it lowers the sintering temperature. This work investigated the influence of sintering dwell time at 1400oC on the properties of 4 wt% niobia doped alumina. The sintered ceramics were characterized by scanning electron microscopy (SEM), and X rays diffraction (XRD) with Rietveld refinement. Measurements of density, average grain size, hardness, and elastic constants were also performed. The results showed that the porosity depend on the time sintering and this influence on the elastic properties. Longer sintering times improved densification and with this the Young's Modulus.

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.

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