Preparation of the Al2O3/3Y-TZP Ceramics by Microwave Sintering under Low Temperature

2013 ◽  
Vol 477-478 ◽  
pp. 1238-1241
Author(s):  
Jun Ming Luo ◽  
Ji Lin Xu ◽  
Hong Yan Zuo ◽  
Jun Huang
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Relative Density ◽  
Bending Strength ◽  
Microwave Sintering ◽  
Spherical Particles ◽  
Ceramic Samples ◽  
Coprecipitation Process

Nanometer Al2O3/3Y-TZP powders were prepared by coprecipitation process and the Al2O3/3Y-TZP ceramics were prepared by microwave sintering under relatively low temperature. The relative density, bending strength and fracture toughness of the Al2O3/3Y-TZP ceramic samples were studied. The results showed that the Al2O3/3Y-TZP powders exhibited fine and homogeneous near-spherical particles with the size of 40-60 nm. With increasing the sintering temperatures, all of the relative density, bending strength and fracture toughness of the ceramic samples increased firstly, reaching the maximum values of 99.1%, 1236 MPa and 10.89 MPa·m1/2at 1250 °C respectively, and then decreased.

scholarly journals Mechanical properties of microwave sintered Si3N4-based ceramics

2002 ◽  
Vol 34 (3) ◽  
pp. 223-229 ◽  
Author(s):  
O.I. Getman ◽  
V.V. Holoptsev ◽  
V.V. Panichkina ◽  
I.V. Plotnikov ◽  
V.K. Soolshenko
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Normal Pressure ◽  
Ceramic Materials ◽  
Particle Sizes ◽  
Phase Measurements ◽  
Ceramic Samples ◽  
Mean Size ◽  
The Mean

The mechanical properties and microstructure formation processes in Si3N4+3% AI2O3+5% Y2O3(Yb2O3) ceramic compacts sintered under microwave heating (MWH) and under traditional heating (TH) were investigated. The initial ceramic materials were powder blends of silicon nitride with oxides. The mean powder particle sizes were 0.5-1.0 mim. The content of alfa-phase in the Si3N4 powder was more than 95 %. The samples were sintered at 1800BC in nitrogen at normal pressure, the heating rate in all experiments was 60BC/min. The Vickers hardness (HV), fracture toughness (K1C) and bending strength (on) were determined. The microstructures of fracture surfaces of samples were studied by SEM. Quantitative microstructure analysis was carried out. It was shown that the values of HV and Kic of ceramic samples sintered under MWH at 1800BC rose steadily with the sintering time. This caused an increase in density, which reached maximum as fast as after 30 min of the MWH sintering; the mass loss at that time amounted to 3-4 %. The porosity of sintered samples with an addition of yttria was less than 1 %, that of ytterbia was greater, 2.4 %. For similar values of relative density, the hardness and fracture toughness of ceramic samples produced under MWH were higher as compared with those of samples sintered under TH. The microstructure of samples had the form of elongated grains in a matrix of polyhedral grains of the beta-Si3N4 phase. Measurements showed the mean size of grains in samples produced by MWH to be greater that in samples produced by TH. A larger number of elongated grains were formed. It was concluded that for sintering under MWH of Si3N4-based ceramics the growth of elongated beta-Si3N4 grains and formation of a "reinforced" microstructure were promoted and thereby improved the mechanical properties of such ceramics.

scholarly journals Study of the Comparative Effect of Sintering Methods and Sintering Additives on the Microstructure and Performance of Si3N4 Ceramic

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2142 ◽  
Author(s):  
Liangliang Yang ◽  
Allah Ditta ◽  
Bo Feng ◽  
Yue Zhang ◽  
Zhipeng Xie
Keyword(s):  
Phase Transition ◽  
Thermal Conductivity ◽  
Fracture Toughness ◽  
Relative Density ◽  
Transition Rate ◽  
Bending Strength ◽  
Si3n4 Ceramic ◽  
Sintering Additives ◽  
The Difference ◽  
And Performance

The Si3N4 ceramics were prepared in this study by gas pressure sintering (GPS) and spark plasma sintering (SPS) techniques, using 5 wt.% Yb2O3–2 wt.% Al2O3 and 5 wt.% CeO2–2 wt.% Al2O3 as sintering additives. Based on the difference in sintering methods and sintering additive systems, the relative density, phase composition, phase transition rate, microstructure, mechanical properties, and thermal conductivity were comparatively investigated and analyzed. SPS proved to be more efficient than GPS, producing higher relative density, bending strength, hardness, and thermal conductivity of Si3N4 ceramic with both additive systems; however, the phase transition rate and fracture toughness were lower. Similarly, higher bending strength, hardness, and thermal conductivity were achieved with Yb2O3–Al2O3 than CeO2–Al2O3 in the case of GPS and SPS, and only the relative density, fracture toughness, and phase transition rate were lower.

Microstructure and Properties of Al2O3-ZrO2(n) Composite Ceramics Prepared by Microwave Sintering

2010 ◽  
Vol 177 ◽  
pp. 364-368
Author(s):  
Wen He ◽  
Yun Long Ai ◽  
Chang Hong Liu ◽  
Jian Ping Zhang ◽  
Jia Yuan Ding
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
Bending Strength ◽  
Phase Transfer ◽  
Microwave Sintering ◽  
Abrasive Particle ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Composite Ceramics ◽  
Alumina Matrix

Al2O3-ZrO2(n) composite ceramics were prepared by microwave sintering. The properties and microstructure were investigated, including vickers hardness, fracture toughness, bending strength, wear resistance and heat-shocking resistance. The results show that the properties and microstructure of alumina matrix ceramics are affected by the addition of nano-ZrO2 particles. When the content of ZrO2 is 15vol%, the hardness, fracture toughness and bending strength of the Al2O3-ZrO2 composites reach maximum values 13350MPa, 6.41MPa•m1/2 and 502MPa, respectively. The wear resistance of alumina matrix ceramics are improved only on the condition of adding an appropriate amount of nano-ZrO2. The wear mechanism of the composites are abrasive particle wear and adhesion wear co-existing. The crack propagation rate of Al2O3 matrix ceramics decreases remarkably with the addition of nano-ZrO2 particles. The mechanisms of ZrO2 improving the heat-shocking resistance of alumina matrix ceramics are mainly phase transfer toughening. Nano-ZrO2 particles exist in the intragranular and grain boundary of alumina matrix ceramics, and exist intragranular structures.

Effect of Holding Time on Microstructure and Properties of VC/Fe Composite

2012 ◽  
Vol 723 ◽  
pp. 353-357
Author(s):  
Guo Jun Zhang ◽  
Zhi Ping Sun ◽  
Li Yan Zou
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Relative Density ◽  
Bending Strength ◽  
Holding Time ◽  
Microstructure And Properties ◽  
Microstructure And Mechanical Properties ◽  
Relationship Of ◽  
The Relationship ◽  
Better Than

The microstructure and mechanical properties of samples were examined, and the relationship of structure and mechanical properties for VC/Fe composite sintered at different holding time were studied. Holding time can influence the mechanical properties, with the holding time rising, when the holding time is 80 min, the hardness is Max, it’s 10.71 GPa, the enhancing range is 37.66%; The relative density changes slower from 60 to 100 min; when the holding time is 60 minutes, fracture toughness and bending strength of material is 16.17 MPa•m 1/2 and 1070 MPa, it’s better than before.

Preparation and Characterization of Al2O3/ZrO2 Composite Ceramics

2016 ◽  
Vol 697 ◽  
pp. 372-376 ◽  
Author(s):  
Yin Yan Ju ◽  
Xue Xian Gan ◽  
Jie Guang Song ◽  
Fang Wang ◽  
Wang Nian Zhang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Hydrothermal Method ◽  
Atmospheric Pressure ◽  
Bending Strength ◽  
Raw Material ◽  
Low Temperature Sintering ◽  
Composite Ceramics

Alumina-zirconia (Al2O3-ZrO2) composite ceramics were prepared by means of cross spraying and hydrothermal method under atmospheric pressure with nanometer powders doped with ZrO2 as the raw material. Then, the prepared powders and ceramics were characterized by SEM, XRD and BET methods. The results showed that combining cross spraying with hydrothermal method under atmospheric pressure could improve the dispersity of the ZrO2 composite ceramics nanopowders, while adding Al2O3 accelerated the low temperature sintering for 3Y-ZrO2 and improved the bending strength, fracture toughness and density of ZrO2 composite ceramics. In addition, through optimization the bending strength and fracture toughnessof the obtained ceramic, were 1,150 MPa and 8.2 MPa∙m1/2 respectively.

Effects of Ti(C,N) Nanoparticles on Mechanical Properties of the Si3N4 Ceramics

2011 ◽  
Vol 80-81 ◽  
pp. 119-122
Author(s):  
Qian Li ◽  
Fu Sheng Zhu ◽  
Zhi Meng Xiu ◽  
Xu Dong Sun
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Aspect Ratio ◽  
Relative Density ◽  
Hot Pressing ◽  
Bending Strength ◽  
Lateral Growth ◽  
Toughening Mechanism ◽  
Vacuum Sintering ◽  
Crack Bridging

Si3N4-Ti(C,N) nanocomposites fabricated by vacuum hot pressing with Al2O3 and Y2O3 as additives were investigated. The results showed that the α-Si3N4 phase converted completely into whisker-shaped β-Si3N4 grains after vacuum sintering at 1700°C. Suitable addition and well dispersion of the Ti(C,N) particles can restrained the lateral growth of the β-Si3N4 grains, increasing aspect ratio of the β-Si3N4 grains and improving bending strength of the composites. Fracture toughness of the composites is higher than that of the β-Si3N4 ceramics, and the main toughening mechanism is crack bridging due to the higher aspect ratio of the β-Si3N4 grains.With the addition of 1vol% of Ti(C,N), the composite has a relative density of 99.31%, Vicker’s hardness of 15.9 GPa, bending strength of 993 MPa, and fracture toughness of 9.9 MPa·m1/2.

Mechanical Properties of ZrB2-Based Ceramics Reinforced by Nano-SiC Whiskers

2007 ◽  
Vol 353-358 ◽  
pp. 1564-1567 ◽  
Author(s):  
Hai Long Wang ◽  
Chang An Wang ◽  
Rui Zhang ◽  
Xing Hu ◽  
Dai Ning Fang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Relative Density ◽  
Hot Pressing ◽  
Bending Strength ◽  
Sintering Process ◽  
Homogeneous Microstructure ◽  
Sic Whiskers ◽  
Xrd Techniques

In this paper, ZrB2-based ceramics containing up to 15 vol% nano-SiC whiskers were prepared by hot pressing at 1950°C under 20MPa pressure in flow argon. SEM and XRD techniques were used to characterize the sintered compacts. A fine and homogeneous microstructure was observed. The relative density of ZrB2-based ceramic containing 10vol% SiC whiskers reached to 97.7%. The bending strength and fracture toughness of the composite were 550 MPa and 8.08 MPa·m1/2 respectively, while those of the monolithic ZrB2 ceramic (0 vol% SiC whiskers added) were 424 MPa and 4.52 MPa·m1/2 respectively. The grain size of the ZrB2-based ceramics was reduced greatly by the addition of nano-SiC whiskers during the sintering process.

Effect of Sintering Pressure on Mechanical Properties of BN-Si3N4 Ceramic Composites Prepared by Spark Plasma Sintering

2016 ◽  
Vol 697 ◽  
pp. 188-192
Author(s):  
Jia Xin An ◽  
Wen Dong Xue ◽  
Feng Rui Zhai ◽  
Ruo Meng Xu ◽  
Jia Lin Sun
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Relative Density ◽  
Spark Plasma Sintering ◽  
Bending Strength ◽  
Raw Materials ◽  
Ceramic Composites ◽  
Composite Ceramics ◽  
Plasma Sintering ◽  
Spark Plasma

BN-Si3N4 composite ceramic wave-transparent materials with excellent mechanical properties were prepared by spark plasma sintering (SPS) using h-BN and α-Si3N4 powders as raw materials, Al2O3 and Y2O3 as sintering aids. The influence of sintering pressure on density and mechanical properties of BN-Si3N4 composite ceramics were studied. The phases were observed by X-ray diffraction (XRD), and the microstructures were identified by scanning electron microscopy (SEM). The results showed that with the sintering pressure increases, the relative density, bending strength and fracture toughness of the composite ceramics were significantly increased, and the porosity decreased rapidly. The effects of pressure on the properties of the composite ceramics was not significant at >40MPa, so 40MPa is optimal for the composite ceramics to gain good overall performance, i.e. the relative density was 89.1%, the porosity was 2.3%, the bending strength reached 215.4 MPa, and the fracture toughness was 3.1/MPa·m1/2.

Effect of Nano-Al2O3 on the Microstructure and Properties of ZrO2 Dental Materials Prepared by Microwave Sintering

2014 ◽  
Vol 618 ◽  
pp. 3-7 ◽  
Author(s):  
Yun Long Ai ◽  
Xiang Hua Xie ◽  
Wen He ◽  
Bing Liang Liang ◽  
Wei Hua Chen
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Microwave Sintering ◽  
Dental Materials ◽  
Transgranular Fracture ◽  
Composite Ceramics ◽  
Obvious Effect ◽  
Size Uniformity ◽  
Mutual Relations

Al2O3(x)/ZrO2composite ceramics were successfully prepared by microwave sintering. The influence of variety content of nanoAl2O3on mechanical properties and microstructure of ZrO2dental materials were studied, and analysied the mutual relations of chemical composition, mechanical properties and microstructure to investigate the reason of strengthening and toughening. Results indicated that The relative density of the Al2O3(x)/ZrO2composite ceramics reached more than 96.8%.The HV hardness ,bending strength and fracture toughness presented excellent mechanical properties as 12.5GPa, 753.8MPa and 11.8MPa·m1/2with the content of nanoAl2O3was 7.5%. Compared with that of pure ZrO2ceramics, the bending strength and the fracture toughness were improved 19% and 96%, respectively. The main crystal phases in this composite ceramics were t-ZrO2and α-Al2O3.The nanoAl2O3have a obvious effect on the strength and toughness of ZrO2based ceramics. The reason of strengthening and toughening mainly the additions reduced the ZrO2grains growth and promoted grains size uniformity, and changed the fracture mode from transgranular fracture to intergranular fracture characteristics.

Mechanical Properties and Oxidation Resistance of Hot Pressed B4C Ceramics Material

2011 ◽  
Vol 233-235 ◽  
pp. 2272-2275
Author(s):  
Xin Yan Yue ◽  
Bi Shuang Chen ◽  
Jing Zhao ◽  
Hong Qiang Ru ◽  
Wei Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Relative Density ◽  
Oxidation Resistance ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Experimental Results ◽  
Pressing Method

B4C ceramics were obtained using hot-pressing method. The effect of different sintering temperatures on the microstructures and mechanical properties of B4C ceramics were investigated. Oxidation resistances were studied over the range 600-850°C. The experimental results showed that the relative density, bending strength and fracture toughness all increased first and then decreased with increasing the sintering temperature. The Vickers-hardness increased as the sintering temperature increasing. When the sintering temperature was 1950°C, the B4C ceramics showed the optimized properties. The values of its relative density, Vickers-hardness, bending strength and fracture toughness were 99.1%, 34.0 GPa, 524.6 MPa and 6.56 MPa·m1/2, respectively.

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