Preparation of the System of MgO-CaO-SiO2-Al2O3-Y2O3 Wear-Resistant Alumina Ceramics

2014 ◽  
Vol 941-944 ◽  
pp. 542-546 ◽  
Author(s):  
Yuan Xiong ◽  
Bo Lin Wu

In order to improve the wear resistance and reduce the sintering temperature of alumina ceramics, Y2O3powder added in the system of MgO-CaO-SiO2-Al2O3alumina ceramics were prepared by the technique of pressureless sintering. The properties of the ceramic samples were investigated by the measurements of bulk density, wear rate, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the wear rate of alumina ceramic contenting Y2O3 of the 0.8wt% is 0.041‰. Adding the yttrium oxide to the raw materials and then calcine them to ceramics, which can reduces the sintering temperature, promote the densification and improve wear-resistant property of alumina ceramics.

2011 ◽  
Vol 399-401 ◽  
pp. 855-859
Author(s):  
Ting Ting Wu ◽  
Bo Lin Wu

In order to improve the acid resistance and reduce the apparent density of fracturing proppants, TiO2 powder added in the system of BaO-MgO-Al2O3 fracturing proppants were prepared by the technique of pressureless sintering. The properties of the samples were investigated by the measurements of acid solubility, X-ray diffraction and scanning electron microscopy. The results show that the acid solubility of alumina matrix fracturing proppants contenting TiO2 of the 4wt% and BaO/MgO with the ratio of 3:7 is 0.15%. It is an important development in acid resistance performance of fracturing proppants research on laboratory. TiO2 is added to the raw materials and then calcine them to ceramics, which can reduces the sintering temperature, promote the densification and improve acid-resistant property of fracturing proppants.


2014 ◽  
Vol 1061-1062 ◽  
pp. 83-86
Author(s):  
Hong Wu ◽  
De Yi Zheng

In this paper, the effects of different sintering temperature on the microstructure and piezoelectric properties of Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3(PNZZT) ceramic samples were investigated. The Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3 ceramics materials was prepared by a conventional mixed oxide method. In the period of the experiment, the relationship between crystallographic phase and microstructure were analyzed by X-ray diffraction(XRD) and scanning electron microscopy(SEM) respectively. The XRD patterns shows that all of the ceramic samples are with a tetragonal perovskite structure. Along with sintering temperature increased and the x is 0.03, the grain size gradually become big. Through this experiment, it has been found that when the x is 0.03 and sintered at 1130°C for 2 h, the grains grow well, the grain-boundary intersection of the sample combined well and the porosity of the ceramics decreased, an excellent comprehensive electrical properties of the Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3 samples can be obtained. Its best electrical properties are as follows: dielectric constant (ε) is 1105, dielectric loss(tg) is 0.017, electromechanical coupling coefficient (Kp) is 0.287, piezoelectric constant(d33) is 150PC/N


2011 ◽  
Vol 335-336 ◽  
pp. 699-703
Author(s):  
Hui Hui Tan ◽  
Zhu Xing Tang ◽  
Xia Zhao ◽  
He Zhang

This paper introduces Si2ON2-SiC ceramic fabricated by pressureless sintering method and studies the effect of additives, nitriding temperatures on bulk density, porosity, phase composition and microstructure. It is discovered that additives MgO, CeO2 can increase the densities of Si2ON2-SiC ceramic apparently, and MgO additive has a better effect than CeO2. Nitriding temperature also is an important factor. The bulk density of the specimen with MgO additive reaches maximum at 1.91 g/cm3 when sintered at 1450 °C, and the bulk density of specimen with CeO2 additive is 1.86 g/cm3 at the same condition while the bulk density of the specimen without additive is only 1.75 g/cSuperscript textm3. The X-ray diffraction and scanning electron microscopy of the specimens show that the amount of Si2ON2 increase with the sintering temperature increase. But when the temperature is higher than 1500 °C the Si2ON2 grains will decompose into Si3N4, and Si2ON2 will vanish at 1550 °C


2016 ◽  
Vol 680 ◽  
pp. 257-260
Author(s):  
Meng Yun Dong ◽  
Cheng Zhang ◽  
Jin Feng Xia ◽  
Hong Qiang Nian ◽  
Dan Yu Jiang

CaF2 nano-power was prepared by direct precipitation methods with Ca(NO3)2 and KF as raw materials. The influences of presintering temperature and sintering temperature on the particle size and distribution of CaF2 nano-power were studied by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM). This study provided an experimental method for preparation of CaF2 nano-power. The results show that the best presintering temperature of CaF2 nano-power is 500°C and the best sintering temperature of CaF2 ceramic is 900°C.


Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1510 ◽  
Author(s):  
Dunlei Su ◽  
Gongbing Yue ◽  
Qiuyi Li ◽  
Yuanxin Guo ◽  
Song Gao ◽  
...  

In this study, a variety of industrial solid wastes, including petroleum coke desulfurization slag, fly ash and carbide slag with natural resource bauxite, were used as raw materials to prepare high belite suphoaluminate cement, which contains a certain CaSO4 content without adding natural gypsum to the clinker. The sintering temperature, mineral composition, and the physical and mechanical properties of the cement clinkers were investigated. The techniques adopted included a comprehensive thermal analysis (DSC-TG), X-ray diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM). The results revealed that it is completely feasible to prepare high belite sulphoaluminate cement with the various industrial solid wastes mentioned above and the utilization rate of the solid wastes is up to 80%. The sintering temperature ranges from 1225 °C to 1350 °C, and the optimal sintering temperature is approximately 1300 °C. The clinkers prepared at 1300 °C set and harden quickly and have a slightly higher water requirement of normal consistency. The mechanical strength is greatly affected by the CaSO4 and 3CaO·3Al2O3·CaSO4 contents and the most reasonable CaSO4 content is 15%.


2015 ◽  
Vol 1087 ◽  
pp. 420-423
Author(s):  
Marwan Zakaria ◽  
Siti Rodiah Karim ◽  
Nur Azam Badarulzaman

This paper focused on fabrication of Al-6vol%SnPb from recycled Aluminium and recycled solder and its characterization in different sintering temperature. Al-20SnPb was fabricated by using cold forging process of flakes chip raw materials. Constant pressure (56.4 MPa) was used to implement cold forging process. Various sintering temperature (200 0C, 250 0C, 300 0C and 3500C) was studied to obtain the optimum hardness properties. The diffraction pattern of X-Ray diffraction (XRD) reveals the influence of varying sintering temperature of Al-6vol%SnPb. Vickers hardness result also support that, optimum result obtained is at sintering temperature 300 °C.


2012 ◽  
Vol 512-515 ◽  
pp. 500-504 ◽  
Author(s):  
Xing Yong Gu ◽  
Shao Ling Wu ◽  
Ai Hua Zhang ◽  
Ting Luo ◽  
Yun Xia Chen

To improve the thermal conductivity of alumina ceramics, different inorganic materials such as AlN, BN, Si3N4 and SiC which own high thermal conductivity were integrated with 96% alumina ceramic. The effect of addition of AlN, BN, Si3N4 and SiC on water absorption, flexural strength and thermal conductivity of the as-prepared alumina-based composite ceramics were investigated. Field emission scanning electron microscopy (FESEM) and X-ray diffractometer (XRD) were employed to characterize the microstructure and phase compositions of the composites. The results showed that sintering temperature of 96% alumina ceramic matrixes were improved in varying degree due to adding AlN, BN, SiC and Si3N4. A small quantity of Al6Si2O13 crystals were formed in the case of adding Si3N4 and SiC, which is due to the oxidation of Si3N4 and SiC into SiO2 in the air and the subsequent reaction with alumina. At appropriate firing temperature, the flexural strength of the composites with the addition of AlN is the best and higher than corundum matrixes. Meanwhile, the thermal conductivity of the composites with AlN has 110% improvement. It is obvious that AlN with high thermal conductivity is suitable for improving the thermal conductivity of corundum ceramics.


2016 ◽  
Vol 848 ◽  
pp. 262-271
Author(s):  
Wen Yan Cheng ◽  
Shi Jia Gu ◽  
Bei Ying Zhou ◽  
Lian Jun Wang ◽  
Wei Luo ◽  
...  

A series of ytterbium and erbium co-doped sodium yttrium fluoride (NaYF4:Yb3+, Er3+) ceramics have been successfully prepared by pressureless sintering. The ceramic samples were characterized by X-ray diffraction (XRD), photoluminescence (PL), density and field emission scanning electron microscope (FESEM). The results showed that the phases of the NaYF4:Yb3+, Er3+ ceramic samples transformed when the sintering temperature was changed. The ceramic samples sintered below 600 oC contained both cubic α-NaYF4:Yb3+, Er3+ and hexagonal β-NaYF4:Yb3+, Er3+. The sample sintered at 600oC is the pure hexagonal β-NaYF4:Yb3+, Er3+. When the sintering temperature is above 600 oC, the ceramic samples present the α-NaYF4:Yb3+, Er3+ again. The fluorescence intensity increased firstly and then decreased with the sintering temperature increasing. The luminous intensity of the sample sintered at 600 oC was the highest. The densities of as-prepared ceramic sample increased with the sintering temperature rising. The samples sintered at 600 oC with different holding time possessed the similar crystal phases (β-NaYF4:Yb3+, Er3+) and fluorescence intensity. As the holding time increased, the densities of the samples increased. To obtain more dense ceramics, the ceramics using β-NaYF4:Yb3+, Er3+ powders were prepared by spark plasma sintering (SPS). The maximum relative density reached 97%.


2012 ◽  
Vol 512-515 ◽  
pp. 28-31 ◽  
Author(s):  
Meng Qi Li ◽  
Hong Xiang Zhai ◽  
Zhen Ying Huang

A high purity of Ti2AlC powder has been synthesized by pressureless sintering a mixture of Ti-Al-TiC-Sn (Sn as an additive) powders. Four recipes with different mole ratios of Ti-Al-TiC-Sn were examined at sintering temperature from 1400°C to 1480°C. A high purity of Ti2AlC powder can be obtained by sintering all these four recipes at temperature 1450°C for 10 min in an Ar atmosphere. The synthesis of Ti2AlC on this large mole ratio scale of starting materials is associated with the evaporation of Al at high temperature and the structure stability of Ti2AlC. From the X-ray diffraction analysis, a reaction path for the Ti2AlC formation is proposed. Scanning electron microscopy was also used to characterize the samples.


2012 ◽  
Vol 535-537 ◽  
pp. 2567-2570
Author(s):  
Dong Hai Zhu ◽  
Xue Ying Nai ◽  
Qian Qian Song ◽  
Shan Yun ◽  
Yong Xing Zhang ◽  
...  

Ba2B5O9Cl whiskers with uniform morphology were synthesized by a simple flux method, using BaCl2•2H2O, H3BO3 as the starting materials, and KCl as the flux. The products were characterized by X-ray diffraction (XRD) and scanning electron microcopy (SEM), and the optimum conditions for preparing high quality Ba2B5O9Cl whiskers were studied. Results show that a sintering temperature around 700 °C, an Ba/B mole ratio of 1:3 and a raw materials to flux mass ratio of 1:2 lead to uniform orthorhombic Ba2B5O9Cl whiskers with a diameter of 0.4-1.0 µm and a length of 10-25 µm.


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