Microstructure and Mechanical Properties of ZrB2/h-BN Multiphase Ceramics by Low-Temperature Reactive Sintering

2016 ◽  
Vol 697 ◽  
pp. 510-514 ◽  
Author(s):  
Feng Rui Zhai ◽  
Ke Shan ◽  
Ruo Meng Xu ◽  
Min Lu ◽  
Zhong Zhou Yi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Relative Density ◽  
Fracture Strength ◽  
Solid Phase ◽  
Raw Materials ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Microstructure And Mechanical Properties ◽  
Multiphase Ceramics ◽  
Strength And Toughness

In the present paper, the ZrB2/h-BN multiphase ceramics were fabricated by SPS (spark plasma sintering) technology at lower sintering temperature using h-BN, ZrO2, AlN and Si as raw materials and B2O3 as a sintering aid. The phase constitution and microstructure of specimens were analyzed by XRD and SEM. Moreover, the effects of different sintering pressures on the densification, microstructure and mechanical properties of ZrB2/h-BN multiphase ceramics were also systematically investigated. The results show that the ZrB2 was obtained through solid phase reaction at different sintering pressures, and increasing sintering pressure could accelerate the formation of ZrB2 phase. As the sintering pressure increasing, the fracture strength and toughness of the sintered samples had a similar increasing tendency as the relative density. The better comprehensive properties were obtained at given sintering pressure of 50MPa, and the relative density, fracture strength and toughness reached about 93.4%, 321MPa and 3.3MPa·m1/2, respectively. The SEM analysis shows that the h-BN grains were fine and uniform, and the effect of sintering pressure on grain size was inconspicuous. The distribution of grain is random cross array, and the fracture texture was more obvious with the increase of sintering pressure. The fracture mode of sintered samples remained intergranular fracture mechanism as sintering pressure changed, and the grain refinement, grain pullout and crack deflection helped to increase the mechanical properties.

The Synthesis and the Thermal Properties of CaZr4(PO4)6 Materials

2013 ◽  
Vol 341-342 ◽  
pp. 69-73
Author(s):  
Long Su ◽  
Wan Mei Sui ◽  
Yu Jie Liu
Keyword(s):  
Thermal Expansion ◽  
Relative Density ◽  
Phase Structure ◽  
Solid Phase ◽  
Raw Materials ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Thermal Expansion Property ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion

CaZr4(PO4)6 ceramics were prepared with solid reaction of two-steps method. CaZr4(PO4)6 powders were synthesized by solid-phase reaction with Ca (OH)2, ZrO2 and (NH4)2HPO4 as raw materials. Then the powders precursor were sintered to CaZr4(PO4)6 ceramics with single phase structure at 1400°C for 8 hours. The relative density was measured, the phase structure of the materials synthesized at different temperatures and the average coefficients of thermal expansion were investigated. The results showed that the relative density of CaZr4(PO4)6 ceramics sintered at 1400°C was 93%. The average thermal expansion coefficients was 1.8×10-6/°C from 25°C to 1400°C. The CaZr4(PO4)6 ceramics obtained possesses low thermal expansion property in a broad range of temperatures.

scholarly journals Fe3O4@C Nanoparticles Synthesized by In Situ Solid-Phase Method for Removal of Methylene Blue

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 330
Author(s):  
Hengli Xiang ◽  
Genkuan Ren ◽  
Yanjun Zhong ◽  
Dehua Xu ◽  
Zhiye Zhang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Solid Phase ◽  
Raw Materials ◽  
Phase Method ◽  
Maximum Adsorption Capacity ◽  
High Catalytic Activity ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
High Concentrations

Fe3O4@C nanoparticles were prepared by an in situ, solid-phase reaction, without any precursor, using FeSO4, FeS2, and PVP K30 as raw materials. The nanoparticles were utilized to decolorize high concentrations methylene blue (MB). The results indicated that the maximum adsorption capacity of the Fe3O4@C nanoparticles was 18.52 mg/g, and that the adsorption process was exothermic. Additionally, by employing H2O2 as the initiator of a Fenton-like reaction, the removal efficiency of 100 mg/L MB reached ~99% with Fe3O4@C nanoparticles, while that of MB was only ~34% using pure Fe3O4 nanoparticles. The mechanism of H2O2 activated on the Fe3O4@C nanoparticles and the possible degradation pathways of MB are discussed. The Fe3O4@C nanoparticles retained high catalytic activity after five usage cycles. This work describes a facile method for producing Fe3O4@C nanoparticles with excellent catalytic reactivity, and therefore, represents a promising approach for the industrial production of Fe3O4@C nanoparticles for the treatment of high concentrations of dyes in wastewater.

Fabrication of Lithium Silicate Doped with Lithium Titanate by Solid-State Reaction and its XRD Study

2012 ◽  
Vol 624 ◽  
pp. 200-203
Author(s):  
Yu Tian Wang ◽  
You Dong Cao ◽  
Jin Hu ◽  
Wei Jun Zhang ◽  
Da Ping Wu ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Solid Phase ◽  
Raw Materials ◽  
Xrd Analysis ◽  
Lithium Titanate ◽  
Lithium Silicate ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Scanning Calorimetry

Fabrication of lithium silicate powder containing lithium titanate by solid phase reaction method. LiFabrication of lithium silicate powder doped with lithium titanate by solid-state reaction. Take lithium carbonate, silicon dioxide and titania as raw materials and then these powders were mixed according to the different ratios and grinded in an agate mortar for 15 min. And then the mixture were dried at 80°C. Finally, the samples were sintered in vacuum tube furnace at 750, 800, 850 and 900°C for 2h. Thermogravimetric analysis, differential scanning calorimetry and XRD analysis were carried out systematically in this paper. The reaction process and mechanism at different temperatures and the effect of the different ratios and sintering temperature were discussed. Experimental results showed that lithium titanate component increased with increasing amount of titanium dioxide. While the mixture were sintered at 900°C for 2h, there would have lithium silicate and lithium titanate phase.

Needle-Like Mullite Ceramic Prepared by Sol-Gel Process

2011 ◽  
Vol 233-235 ◽  
pp. 2640-2643 ◽  
Author(s):  
Fu Sheng Song
Keyword(s):  
Powder Diffraction ◽  
Solid Phase ◽  
Raw Materials ◽  
Sol Gel ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Mullite Ceramic ◽  
X Ray ◽  
Sol Gel Process ◽  
Ceramic Blocks

Using tetraethoxysilane, aluminum nitrate and aluminum fluoride as raw materials, the precursor of mullite was prepared by sol-gel process. When the precursor sintered at 1200°C, mullite ceramic was obtained. Differential thermal analysis, X-ray powder diffraction and scanning electron microscope were used to characterize the dried mullite gel and ceramic blocks. The results suggest mullite is synthesized by solid-phase reaction mechanism. X-ray powder diffraction indicates mullite is the main crystals phase in the ceramic specimen. SEM micrograph shows the mullite grains in the shape of short rod with length of 20 um when sintered at 1200 °C for 2 h and the grains grown up to acicular with length of more than 50 um when the treating time under 1200 °C achieved to 4 h.

scholarly journals Effect of Waste Glass Powder on Phase, Microstructure and Mechanical Properties of Mullite Based Porous Ceramics with Coal-series Solid Waste as Raw Materials

2020 ◽  
Author(s):  
Wei Lian ◽  
Yan Liu ◽  
Wenjie Wang ◽  
Yangtao Dong ◽  
Sheng Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Glass Powder ◽  
Solid Phase ◽  
Raw Materials ◽  
Porous Ceramics ◽  
Volume Density ◽  
Synthesis Temperature ◽  
Phase Method ◽  
Microstructure And Mechanical Properties ◽  
Solid Phase Method

Abstract Mullite based porous ceramics were successfully prepared by using a solid-phase method with gangue, slime and sawdust as raw materials. The effects of the content of glass powder and calcining temperature on microstructure and mechanical properties of the samples were systematically studied. It is found that glass powder can prevent the formation of Kyanite and reduce the synthesis temperature of mullite. The samples with 4% glass powder have a large amount of mullite calcined at 1150°C for 3h. Meanwhile, alumina in the sample is completely converted into mullite at 1180°C for 3h. Mullite content reaches 64.2wt%. The minimum apparent porosity is 31.22%, while the maximum volume density and diameter shrinkage are 1.74g/cm 3 and 8.48%, respectively. The ratio of pores of <8μm to those of 8~20μm is varied from 7:2 to 2:7, due to the addition of the glass powder. With increasing content of mullite, the flexural properties of the samples are increased from 7.7MPa to 28.36MPa. Therefore, with solid wastes as the resource, the porous ceramics have a bright prospect.

scholarly journals Formation Mechanism of High-Purity Ti2AlN Powders under Microwave Sintering

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5356
Author(s):  
Weihua Chen ◽  
Jiancheng Tang ◽  
Xinghao Lin ◽  
Yunlong Ai ◽  
Nan Ye
Keyword(s):  
Electron Microscopy ◽  
Formation Mechanism ◽  
High Purity ◽  
Solid Phase ◽  
Raw Materials ◽  
Microwave Sintering ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Scanning Calorimetry ◽  
Transmission Electron

In the present study, high-purity ternary-phase nitride (Ti2AlN) powders were synthesized through microwave sintering using TiH2, Al, and TiN powders as raw materials. X-ray diffraction (XRD), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were adopted to characterize the as-prepared powders. It was found that the Ti2AlN powder prepared by the microwave sintering of the 1TiH2/1.15Al/1TiN mixture at 1250 °C for 30 min manifested great purity (96.68%) with uniform grain size distribution. The formation mechanism of Ti2AlN occurred in four stages. The solid-phase reaction of Ti/Al and Ti/TiN took place below the melting point of aluminum and formed Ti2Al and TiN0.5 phases, which were the main intermediates in Ti2AlN formation. Therefore, the present work puts forward a favorable method for the preparation of high-purity Ti2AlN powders.

scholarly journals STUDY OF TECHNICAL CELLULOSE AS A MATRIX-SORBENT TO DEVELOP EXPRESS ANALYTIC SYSTEM FOR WATER SAFETY CONTROL

2021 ◽  
pp. 351-359
Author(s):  
Tatiana Maslakovа ◽  
Alesya Vurasko ◽  
Inna Pervova ◽  
Pavel Maslakov ◽  
Ludmila Aleshina ◽  
...  
Keyword(s):  
Metal Ion ◽  
Solid Phase ◽  
Raw Materials ◽  
Synthesis Method ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Water Safety ◽  
Safety Control ◽  
Cellulose Matrix ◽  
Indicator Systems

The study presented by the authors is devoted to the study of the properties and the possibility of using technical cellulose from non-wood plant raw materials as a solid-phase matrix to obtain solid-phase reactive indicator systems by the following methods: synthesis method on the base of a hetarylformazane immobilized on a cellulose matrix and development of analytical systems based on preconcentration of the determined metal ion by a matrix with subsequent its «revealing» by the formazan («revealing» method). The article focuses on determination of optimal combinations of chromogenic organic reagents (hetarylformazanes) and cellulose-based matrices for developing solid-phase reaction-based indicator systems. Adsorption features of formazan reagents onto cellulose matrices was studied. It has been established the relation between the reagent molecule structure, composition of cellulose matrix and analytical properties of the test-systems synthesized to determine metal ions. Different approaches were developed and applied to reveal the visually observable and easily measured effect due to cellulose properties as well as properties of hetarylformazanes fixed on the surface of the matrix. This fact allows to control sensitivity and selectivity of solid-phase reactive indicator systems for water quality assessment.

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.

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