scholarly journals Microstructural evolution of h-BN matrix composite ceramics with La-Al-Si-O glass phase during hot-pressed sintering

2021 ◽  
Author(s):  
Baofu Qiu ◽  
Xiaoming Duan ◽  
Zhuo Zhang ◽  
Chen Zhao ◽  
Bo Niu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Microstructural Evolution ◽  
Glass Phase ◽  
Lanthanum Oxide ◽  
Sintering Temperature ◽  
Hexagonal Boron Nitride ◽  
Raw Materials ◽  
Sintering Process ◽  
Composite Ceramics ◽  
Phase Precipitation

AbstractBN/La-Al-Si-O composite ceramics were fabricated by hot-pressed sintering using hexagonal boron nitride (h-BN), lanthanum oxide (La2O3), aluminia (Al2O3), and amorphous silica (SiO2) as the raw materials. The effects of sintering temperature on microstructural evolution, bulk density, apparent porosity, and mechanical properties of the h-BN composite ceramics were investigated. The results indicated that La-Al-Si-O liquid phase was formed during sintering process, which provided an environment for the growth of h-BN grains. With increasing sintering temperature, the cristobalite phase precipitation and h-BN grain growth occurred at the same time, which had a significant influence on the densification and mechanical properties of h-BN composite ceramics. The best mechanical properties of BN/La-Al-Si-O composite ceramics were obtained under the sintering temperature of 1700 °C. The elastic modulus, flexural strength, and fracture toughness were 80.5 GPa, 266.4 MPa, and 3.25 MPa·m1/2, respectively.

scholarly journals Microstructural evolution of h-BN matrix composite ceramics with La-Al-Si-O glass phase during hot-pressed sintering

2020 ◽  
Author(s):  
Baofu Qiu ◽  
Xiaoming Duan ◽  
Zhuo Zhang ◽  
Chen Zhao ◽  
Bo Niu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Elastic Modulus ◽  
Microstructural Evolution ◽  
Glass Phase ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Sintering Process ◽  
Composite Ceramics ◽  
Phase Precipitation

Abstract BN/La-Al-Si-O composite ceramics were fabricated by hot-pressed sintering using h-BN, La2O3, Al2O3 and amorphous SiO2 as the raw materials. The effects of sintering temperature on the microstructural evolution, bulk density, apparent porosity, and mechanical properties of h-BN composite ceramics were investigated. The results indicated that La-Al-Si-O liquid phase was formed during sintering process, which provided an environment for the growth of h-BN grains. With increasing sintering temperature, the cristobalite phase precipitation and h-BN grain growth occurred at the same time, which had the significant influence on the densification and mechanical properties of h-BN composite ceramics. The best mechanical properties of BN/La-Al-Si-O composite ceramics were obtained under sintering temperature of 1700 °C, and the elastic modulus, flexural strength, and fracture toughness were 80.5 GPa, 266.4 MPa and 3.25 MPa·m1/2, respectively.

scholarly journals Microstructural Evolution of H-BN Matrix Composite Ceramics With Amorphous La2O3-Al2O3-SiO2 Glass Phase During Hot Pressing

2020 ◽  
Author(s):  
Baofu Qiu ◽  
Xiaoming Duan ◽  
Zhuo Zhang ◽  
Chen Zhao ◽  
Bo Niu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Microstructural Evolution ◽  
Glass Phase ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Sintering Process ◽  
Hot Press ◽  
Composite Ceramics ◽  
Phase Precipitation ◽  
Hot Press Sintering

Abstract BN-La2O3-Al2O3-SiO2 composite ceramics were fabricated by hot press sintering using h-BN, La2O3, Al2O3 and amorphous SiO2 as the raw materials. The effects of sintering temperature on the microstructural evolution, bulk density, apparent porosity, and mechanical properties of h-BN composite ceramics were investigated. The results indicated that ternary La2O3-Al2O3-SiO2 liquid phase was formed during sintering process, which provided an environment for the growth of h-BN grains. With increasing sintering temperature, the cristobalite phase precipitation and h-BN grain growth occurred at the same time, which had the significant influence on the densification and mechanical properties of h-BN composite ceramics. The best mechanical properties of BN-La2O3-Al2O3-SiO2 composite ceramics were obtained under sintering temperature of 1700 °C, and the elastic modulus, flexural strength, and fracture toughness were 80.5 GPa, 266.4 MPa and 3.25 MPa·m1/2, respectively.

Study on Mechanical Property of Al2O3-Based Composite Ceramics Liner of Heavy-Medium Cyclone

2011 ◽  
Vol 295-297 ◽  
pp. 581-584
Author(s):  
Li Qiang Zhang ◽  
Ping Huo ◽  
Yong Huang ◽  
Peng Li ◽  
Rong Yang
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Mechanical Property ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Composite Ceramics ◽  
Heavy Medium ◽  
Scanning Electron

In laboratory condition, industrial zirconia and alumina were used as raw materials, whose particle size was controlled by ultrafine treatment of mechanical milling. The effects of different firing temperatures and soaking times on mechanical properties of Al2O3-based composite ceramics liner were researched. And the microstructure of samples was studied by scanning electron microscopy (SEM). The results indicate that mechanical properties of samples kept 3 h at sintering temperature of 1600°C with adding 30 wt% zirconia are the best.

scholarly journals Microstructural evolution and mechanical properties of in situ nano Ta4HfC5 reinforced SiBCN composite ceramics

2020 ◽  
Vol 9 (6) ◽  
pp. 739-748
Author(s):  
Bingzhu Wang ◽  
Daxin Li ◽  
Zhihua Yang ◽  
Dechang Jia ◽  
Jingyi Guan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Microstructural Evolution ◽  
Hot Pressing ◽  
Raw Materials ◽  
Hybrid Structure ◽  
Second Step ◽  
Composite Ceramics ◽  
Hot Pressing Sintering ◽  
Reactive Hot Pressing

AbstractThe in situ nano Ta4HfC5 reinforced SiBCN-Ta4HfC5 composite ceramics were prepared by a combination of two-step mechanical alloying and reactive hot-pressing sintering. The microstructural evolution and mechanical properties of the resulting SiBCN-Ta4HfC5 were studied. After the first-step milling of 30 h, the raw materials of TaC and HfC underwent crushing, cold sintering, and short-range interdiffusion to finally obtain the high pure nano Ta4HfC5. A hybrid structure of amorphous SiBCN and nano Ta4HfC5 was obtained by adopting a second-step ball-milling. After reactive hot-pressing sintering, amorphous SiBCN has crystallized to 3C-SiC, 6H-SiC, and turbostratic BN(C) phases and Ta4HfC5 retained the form of the nanostructure. With the in situ generations of 2.5 wt% Ta4HfC5, Ta4HfC5 is preferentially distributed within the turbostratic BN(C); however, as Ta4HfC5 content further raised to 10 wt%, it mainly distributed in the grain-boundary of BN(C) and SiC. The introduction of Ta4HfC5 nanocrystals can effectively improve the flexural strength and fracture toughness of SiBCN ceramics, reaching to 344.1 MPa and 4.52 MPa·m1/2, respectively. This work has solved the problems of uneven distribution of ultra-high temperature phases in the ceramic matrix, which is beneficial to the real applications of SiBCN ceramics.

scholarly journals Microstructural evolution and mechanical properties of in situ nano Ta4HfC5 reinforced SiBCN composite ceramics

2020 ◽  
Author(s):  
Bingzhu Wang ◽  
Li Daxin ◽  
Zhihua Yang ◽  
Dechang Jia ◽  
Jingyi Guan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Microstructural Evolution ◽  
Hot Pressing ◽  
Raw Materials ◽  
Hybrid Structure ◽  
Composite Ceramics ◽  
Nano Structure ◽  
Hot Pressing Sintering ◽  
Reactive Hot Pressing

Abstract In this paper, the in situ nano Ta 4 HfC 5 reinforced SiBCN-Ta 4 HfC 5 composite ceramics were prepared by a combination of two-step mechanical alloying and reactive hot-pressing sintering. The microstructural evolution and mechanical properties of the SiBCN-Ha 4 HfC 5 were studied. After the first-step milling of 30 h, the raw materials of TaC and HfC undergone crushing, cold sintering and short-range interdiffusion to finally obtain the high pure nano Ta 4 HfC 5 . A hybrid structure of amorphous SiBCN and nano Ta 4 HfC 5 was obtained by adopting a second-step ball-milling. After reactive hot-pressing sintering, amorphous SiBCN has crystallized to nano SiC and turbostratic BN(C) phases while Ta 4 HfC 5 retained the form of nano structure. With the in situ generation of 2.5 wt% Ta 4 HfC 5 , Ta 4 HfC 5 is preferentially distributed within the turbostratic BN(C); however, as Ta 4 HfC 5 content further raised to 10 wt%, it mainly distributed in the grain-boundary of BN(C) and SiC. The introduction of Ta 4 HfC 5 nanocrystals can effectively improve the flexural strength and fracture toughness of SiBCN ceramics, reaching to 344.1 MPa and 4.52 MPa•m 1/2 , respectively.

scholarly journals Pressureless Sintering of YIG Ceramics from Coprecipitated Nanopowders

2021 ◽  
Vol 7 (5) ◽  
pp. 56
Author(s):  
Yimin Yang ◽  
Xiaoying Li ◽  
Ziyu Liu ◽  
Dianjun Hu ◽  
Xin Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Calcination Temperature ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Secondary Phase ◽  
Coprecipitation Method ◽  
Pressureless Sintering ◽  
Densification Behavior ◽  
Sintering Process

Nanoparticles prepared by the coprecipitation method were used as raw materials to fabricate Y3Fe5O12 (YIG) ceramics by air pressureless sintering. The synthesized YIG precursor was calcinated at 900–1100 °C for 4 h in air. The influences of the calcination temperature on the phase and morphology of the nanopowders were investigated in detail. The powders calcined at 1000–1100 °C retained the pure YIG phase. YIG ceramics were fabricated by sintering at 1200–1400 °C for 10 h, and its densification behavior was studied. YIG ceramics prepared by air sintering at 1250 °C from powders calcinated at 1000 °C have the highest in-line transmittance in the range of 1000-3000 nm. When the sintering temperature exceeds 1300 °C, the secondary phase appears in the YIG ceramics, which may be due to the loss of oxygen during the high-temperature sintering process, resulting in the conversion of Fe3+ into Fe2+.

scholarly journals Effect of Sintering Temperature on Microstructure and Mechanical Properties of Hot-Pressed Fe/FeAl2O4 Composite

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 422
Author(s):  
Kuai Zhang ◽  
Yungang Li ◽  
Hongyan Yan ◽  
Chuang Wang ◽  
Hui Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Hot Press ◽  
Microstructure And Mechanical Properties ◽  
Powder Particles ◽  
Hot Press Sintering ◽  
Sintering Method

An Fe/FeAl2O4 composite was prepared with Fe-Fe2O3-Al2O3 powder by a hot press sintering method. The mass ratio was 6:1:2, sintering pressure was 30 MPa, and holding time was 120 min. The raw materials for the powder particles were respectively 1 µm (Fe), 0.5 µm (Fe2O3), and 1 µm (Al2O3) in diameter. The effect of sintering temperature on the microstructure and mechanical properties of Fe/FeAl2O4 composite was studied. The results showed that Fe/FeAl2O4 composite was formed by in situ reaction at 1300 °C–1500 °C. With the increased sintering temperature, the microstructure and mechanical properties of the Fe/FeAl2O4 composite showed a change law that initially became better and then became worse. The best microstructure and optimal mechanical properties were obtained at 1400 °C. At this temperature, the grain size of Fe and FeAl2O4 phases in Fe/FeAl2O4 composite was uniform, the relative density was 96.7%, and the Vickers hardness and bending strength were 1.88 GPa and 280.0 MPa, respectively. The wettability between Fe and FeAl2O4 was enhanced with increased sintering temperature. And then the densification process was accelerated. Finally, the microstructure and mechanical properties of the Fe/FeAl2O4 composite were improved.

Effects of MgO and Y2O3 on the Microstructure and Mechanical Properties of Al2O3 Ceramics

2013 ◽  
Vol 589-590 ◽  
pp. 572-577 ◽  
Author(s):  
Hua He Liu ◽  
Han Lian Liu ◽  
Chuan Zhen Huang ◽  
Bin Zou ◽  
Ya Cong Chai
Keyword(s):  
Mechanical Properties ◽  
Sintering Temperature ◽  
Hot Press ◽  
Composite Ceramics ◽  
Microstructure And Mechanical Properties ◽  
Suitable Amount ◽  
Hot Press Sintering ◽  
Grains Refinement ◽  
Better Than

Al2O3-MgO, Al2O3-Y2O3 and Al2O3-MgO-Y2O3 composite ceramics were fabricated respectively by hot-press sintering technique. With the analysis of the mechanical properties and microstructure, it was found that single additive MgO could be more favorable to the grains’ refinement and densification than Y2O3; the composite additive including both MgO and Y2O3 was better than single additive MgO or Y2O3, because their interactions could improve the mechanical properties of the Al2O3 ceramics; The sintering temperature could be reduced by adding the suitable amount of composite additives.

Use of Sugarcane Bagasse Ashes as Raw Material in the Replacement of Fluxes for Applications on Porcelain Tile

2016 ◽  
Vol 881 ◽  
pp. 383-386 ◽  
Author(s):  
Raimundo J.S. Paranhos ◽  
Wilson Acchar ◽  
Vamberto Monteiro Silva
Keyword(s):  
Mechanical Properties ◽  
Environmental Impact ◽  
Physical Properties ◽  
Sugarcane Bagasse ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Raw Material ◽  
The Cost ◽  
Potential Use ◽  
Porcelain Tile

This study evaluated the potential use of Sugarcane Bagasse Ashes (SBA) as a flux, replacing phyllite for the production of enamelled porcelain tile. The raw materials of the standard mass components and the SBA residue were characterized by testing by XRF, XRD, AG, DTA and TGA. Test samples were fabricated, assembled in lots of 3 units and sintered at temperatures of 1150 ° C to 1210 ° C. The results of the physical properties, mechanical properties and SEM of the sintered samples, showed that the formulation, G4 - in which applied 10% of SBA replacing phyllite, sintering temperature 1210 ° C showed better performance as the previously mentioned properties due to the formation of mullite crystals, meeting the prerequisites of standards for enamelled porcelain tile, while reducing the environmental impact and the cost of production.

Preparation of ZrO2 Composite Ceramics with High Thermal Shock Resistance

2012 ◽  
Vol 455-456 ◽  
pp. 650-654 ◽  
Author(s):  
He Yi Ge ◽  
Jian Ye Liu ◽  
Xian Qin Hou ◽  
Dong Zhi Wang
Keyword(s):  
Mechanical Properties ◽  
Water Absorption ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Sintering Temperature ◽  
Fiber Composite ◽  
Physical And Mechanical Properties ◽  
Composite Ceramics ◽  
Shock Resistance ◽  
Absorption Measurements

The physical and mechanical properties of nanometer ZrO2-ZrO2fiber composite ceramics were studied by introduction of ZrO2fiber. ZrO2composite ceramics at different sintering temperature was investigated by porosity and water absorption measurements, flexual strength and thermal shock resistance analysis. Results showed that ZrO2composite ceramics containing 15 wt% ZrO2fiber with sintering temperature of 1650°C exhibited good mechanical properties and thermal shock resistance. The porosity and the water absorption were 8.84% and 1.62%, respectively. The flexual strength was 975 MPa and the thermal shock times reached 31 times. Scanning electron microscope (SEM) was used to analyze the microstructure of ZrO2composite ceramics.

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