scholarly journals Effect of the sintering temperature on the fabrication of alumina beads

2019 ◽  
Vol 16 (2) ◽  
pp. 125-135
Author(s):  
Ayse KALEMTAS
Keyword(s):  
Sintering Temperature ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Liquid Phase Sintering ◽  
Sintered Ceramic ◽  
Mullite Phase ◽  
Commercial Grade ◽  
Composite Beads ◽  
Sintering Additive ◽  
Dta Analysis

In this study, kaolin bonded alumina-alginate composite beads were fabricated via a facile one-step sol-gel process by using sodium alginate. In order to achieve sintering of the beads at lower sintering temperatures a limited amount of CC31 commercial-grade kaolin was used as a sintering additive (Al2O3:CC31 commercial-grade kaolin=14:1). Produced composite beads were heat treated at 1300°, 1400° and 1500°C for 1 hour to achieve partial densification of the beads. TG-DTA analysis of the CC31 commercial-grade kaolin showed that mullite phase formation took place approximately at 1000°C. However, XRD measurements revealed that there is only alumina phase in the sintered ceramic beads. Due to the low amount of CC31 commercial-grade kaolin, mullite formation was not detectable via XRD analysis. No significant grain growth was observed at the sintered samples depending on the increasing sintering temperature. However, when the sintering temperature was increased, densification ratio and mechanical properties of the produced beads were enhanced significantly. Microstructural investigations of the sintered beads shown that with the help of the liquid phase sintering process, a good chemical bonding was achieved between the alumina particles.

Properties of Silicon Nitride Using Cordierite as Sintering Additives

2007 ◽  
Vol 336-338 ◽  
pp. 313-315
Author(s):  
Miao Jiang ◽  
Feng Hou ◽  
Ting Xian Xu
Keyword(s):  
Silicon Nitride ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Porous Structures ◽  
Reaction Method ◽  
Low Dielectric ◽  
Sintering Additive ◽  
Low Sintering Temperature

Silicon nitride materials with low dielectric properties were prepared using nano and micron silicon nitride powders as raw materials and the green bodies were sintered with cordierite as sintering additive in flowing nitrogen. The additives of cordierite powders prepared by sol-gel method and solidstate reaction method could greatly decrease the sintering temperature. The dielectric constant of materials decreased as sintering temperature fell, whereas the strength showed relatively low as the low sintering temperature. XRD analysis showed the main phase of material was Si2N2O, which indicated that the Si3N4 could be integrated with SiO2. Porous structures were observed by SEM, showing compact sintering cannot be achieved at these temperatures, explaining the low strength.

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.

Low-Temperature Sintering of 3Y-TZP/Glass Composites as All-Ceramic Dental Materials

2007 ◽  
Vol 336-338 ◽  
pp. 1593-1595
Author(s):  
Zheng Qiu Sun ◽  
Hong Yan Miao ◽  
Guo Qiang Tan ◽  
Ao Xia
Keyword(s):  
Grain Size ◽  
Sintering Temperature ◽  
Dental Materials ◽  
Xrd Analysis ◽  
Cold Isostatic Pressing ◽  
Liquid Phase Sintering ◽  
Glass Composites ◽  
All Ceramic ◽  
Mean Grain Size ◽  
The Mean

3Y-TZP ceramics were fabricated with the addition of 10wt% MgO-Al2O3-SiO2 glass additive by cold-isostatic pressing and afterwards liquid-phase sintering at 1200-1400°C for 2 h. The densities of samples sintered at 1300°C for 2 h reaches 99.1%, but further increase of sintering temperature results in the decrease of densities. XRD analysis showed that the cordierite crystals and a small amount of amorphous phase were presented at the grain junctions, and SEM observation indicated that the mean grain size of ZrO2 with round-shape ranged from 200 to 300 nm, which was below the critical transformation size, and the increase in sintering temperature was accompanied with an increase in the mean grain size. The strength and toughness of samples were kept in the range of 396-528 MPa, 4.4-5.8 MPa·m1/2 respectively, which could meet the need of clinical applications of all-ceramic dental materials.

scholarly journals The influence of BaGeO3 on the properties of Ba(Ti1−xSx)O3 ceramics on the basis of sol-gel powders

2019 ◽  
Author(s):  
Roberto Köferstein
Keyword(s):  
Phase Transition ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Synthesis Method ◽  
Particle Sizes ◽  
Dielectric Measurements ◽  
Sintering Additive ◽  
Phase Transition Temperatures

Ba(Ti1−x−y SnxGey )O3 (BTSG-x-y; x = 0, 0.05; y = 0–0.05) powders were synthesized by a sol-gel (SG) method and for comparative purposes also by a mixed-oxide (MO) method. In this system, BaGeO3 functions as sintering additive. Due to smaller particle sizes of the SG powders a higher sintering activity was found, which resulted in reduced grain growth and in a more homogenous grain size distribution for the corresponding ceramics. The dependence on the paraelectric ⇆ ferroelectric phase transition, i.e. the phase transition temperature, thewidth of the transition region and completeness were examined by dielectric measurements,DTA as well as by SEM, EDX and XRD investigations with respect to the BaGeO3 content, synthesis method and sintering temperature. The phase transition temperatures of the SG ceramics are remarkably higher than those of the MO ceramics with the same nominal compositions. The reason is a lower tin concentration within the grains of SG ceramics as confirmed by EDX and XRD investigations. The presence of BaGeO3 in barium titanate–stannate system on the basis of a SG method caused an improved incorporation of tin in theBaTiO3 lattice.

Preparation and electrical properties of gadolinium-doped strontium tungstate electrolyte for SOFC

2020 ◽  
Vol 13 (03) ◽  
pp. 2050010
Author(s):  
Jihai Cheng ◽  
Ming Wang
Keyword(s):  
Electrical Properties ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Combustion Method ◽  
Xrd Analysis ◽  
Doping Amount ◽  
Sintered Ceramic ◽  
Auto Combustion ◽  
Electrical Conductivities ◽  
Text Content

Gadolinium-doped strontium tungstate (Sr[Formula: see text]GdxWO[Formula: see text]) powders were synthesized by the sol–gel auto-combustion method, and their electrical properties were investigated. The phase formation of Sr[Formula: see text]GdxWO[Formula: see text] powders was studied by the X-ray diffraction (XRD) analysis. The characterization of microstructure was carried out on the sintered ceramic discs. Electrochemical impedance spectroscopy (EIS) was used to estimate the electrical properties. The results displayed that these crystalline powders were scheelite-type tetragonal structures and demonstrated higher sinterability. The Sr[Formula: see text]GdxWO[Formula: see text] electrolyte ceramics with a relative density over 95% of the theoretical density were obtained after the sintering process. The electrical conductivities of Sr[Formula: see text]GdxWO[Formula: see text] increased significantly with increasing of doped-Gd[Formula: see text] content and reached [Formula: see text] S[Formula: see text]cm[Formula: see text] at 800∘C, when the doping amount was [Formula: see text]. At last, this study demonstrated that Sr[Formula: see text]GdxWO[Formula: see text] is an effective strategy to optimize middle or low-temperature SOFC.

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.

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.

Particle Coating of Talc with TiO2: Synthesis, Characterization and Photo Catalytic Degradation of Methylene Blue

2013 ◽  
Vol 781-784 ◽  
pp. 157-162
Author(s):  
Ji Pan Lou ◽  
Guo Xin Xue ◽  
Shi Zhen Li ◽  
Juan Wang
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
High Speed ◽  
Sintering Temperature ◽  
Dye Degradation ◽  
Physical Adsorption ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Particle Coating ◽  
Molecular Group

Talc was used as support for synthesis of TiO2-based photocatalyst with varying TiO2loading. A simple sol-gel method was used to impregnate titanium sol into the interlayers of talc with high speed stirring, followed by calcination at different temperature. The XRD analysis and SEM observation indicated that the anatase phases of TiO2were synthesized and individually distributed on the surface of the talc particles. FTIR were used to investigate the molecular group of TiO2/talc. The wettability of talc was improved by TiO2particle coating. The efficiency of the TiO2-talc composites to remove methylene blue from its aqueous solution was evaluated under UV irradiation. Different sintering temperature influenced the catalytic activity, TiO2-talc composites enhanced dye degradation in contrast with physical adsorption of Talc or photo-catalytic of pure TiO2.

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.

Effects of SnO2-SiO2-MgO-Bi2O3-Y2O3 Additions on Liquid Phase Sintering Silicon Nitride

2019 ◽  
Vol 798 ◽  
pp. 254-257
Author(s):  
Sasijuta Wattanarach ◽  
Siripan Nilpairach ◽  
Charusporn Mongkolkachit ◽  
Thanataon Pornphatdetaudom ◽  
Thanakorn Wasanapiarnpong
Keyword(s):  
Low Temperature ◽  
Mass Loss ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Ambient Pressure ◽  
Nitrogen Atmosphere ◽  
Liquid Phase Sintering ◽  
Full Density ◽  
Nitrogen Gas ◽  
Sintering Additive

Si3N4 ceramics were sintered at relatively low temperature of 1400-1650 °C with additives from the SnO2-SiO2-MgO-Bi2O3-Y2O3 system. The degree of densification, α-β transformation, mass loss and microstructure were measured as a function of additives composition, sintering temperature, and nitrogen gas pressure. Specimen prepared from 3 mass% SnO2, 3 mass% SiO2, 3 mass% MgO, 6 mass% Bi2O3, and 5 mass% Y2O3 as the sintering additive could be sintered to almost full density at relatively low temperature as 1550 °C for 2 h under ambient pressure of nitrogen atmosphere. The α-β transformation was not completed at this condition. The mass loss was relatively high due to the evaporation of SiO2, MgO and Bi2O3. However, the resulted dense materials have high bending strength.

Sign in / Sign up

Export Citation Format

Share Document