Influence of Suspensions Rheology on the Properties of Light Weight High Temperature Materials

Light weight materials are produced according to the aerated concrete technology using slurries. In concentrated suspensions pore formation depends on rheological properties such as viscosity, zeta potential and pH. The chemical composition as well as the grain size of raw materials and the sintering temperature have major influence on the pore structure of the final material.

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Preparation and Electrical Property of Calcia Stabilized Zirconia Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.616.157 ◽

2014 ◽

Vol 616 ◽

pp. 157-165 ◽

Cited By ~ 3

Author(s):

Chang Lian Chen ◽

Hong Quan Wang ◽

Jia You Ji ◽

Ma Ya Luo ◽

Bo Wu ◽

...

Keyword(s):

Grain Size ◽

Electrical Property ◽

Arrhenius Equation ◽

Sintering Temperature ◽

Raw Materials ◽

Cubic Phase ◽

Pressureless Sintering ◽

Stabilized Zirconia ◽

Zirconia Ceramics ◽

Sintering Method

In this paper, using ZrO2 and Ca (NO3)•4H2O as raw materials, we prepared a series of calica stabilized zirconia (CSZ) ceramics by pressureless sintering method. The results show that the relative densities of all sintered samples are above 90%, and the sintered samples are composed of cubic, tetragonal and monoclinic ZrO2, and the main phase is cubic ZrO2 and tetragonal ZrO2. The content of cubic phase increases with the increase of sintering temperature and adding CaO content. The grain size of the sintered samples is relatively uniform and some pores exist. Increasing the additive amount of CaO, the conductivity first rises and then decreases, and the conductivity value of the sample containing 5wt% CaO is the maximum. When the sintering temperature is up to 1600 oC, the conductivity of the sample containing 5wt% CaO is up to 0.016S•cm-1 at 800 oC. Furthermore, the conductivity of sintered samples is increasing with the increase of test temperature according to the Arrhenius equation.

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Synthesis of Pr6O11 Doped Zinc Varistors by High-Energy Milling

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.105-106.314 ◽

2010 ◽

Vol 105-106 ◽

pp. 314-316

Author(s):

Guo Quan Qi ◽

Jian Feng Zhu ◽

Hai Bo Mao ◽

Yang Wu ◽

Hai Bo Yang ◽

...

Keyword(s):

Grain Size ◽

Electrical Properties ◽

Milling Time ◽

Sintering Temperature ◽

Raw Materials ◽

High Energy ◽

Linear Coefficient ◽

High Energy Milling ◽

Zno Varistors ◽

Doped Zno

High voltage zinc varistors was synthesized by high energy milling with Pr6O11 doped ZnO-Bi2O3 system as raw materials. The effects of milling time and sintering temperature on the electrical properties were investigated. The results show that high-energy milling decreases the sintering temperature of the ZnO varistors. The material derived from high-energy milling exhibit high density and good electrical properties at the sintering temperature from 1080 to 1180°C. The samples sintered at 1100 °C have average crystalline grain size of about 5 µm with the optimum values of electrical properties, gradient voltage V1mA is 371 V/mm, leakage current IL is 0.62 µA, non linear coefficient α is 60.

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Application of Metakaoline in Autoclaved Aerated Concrete Technology

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1000.174 ◽

2014 ◽

Vol 1000 ◽

pp. 174-177 ◽

Cited By ~ 3

Author(s):

Ondřej Koutný ◽

Tomáš Opravil ◽

Jaromír Pořízka

Keyword(s):

Compressive Strength ◽

Portland Cement ◽

Heat Insulation ◽

Raw Materials ◽

Mineralogical Composition ◽

Raw Material ◽

Concrete Technology ◽

Autoclaved Aerated Concrete ◽

Volume Weight ◽

Aerated Concrete

In these days, autoclaved aerated concrete research points to the utilization of alternative raw materials such as metakaoline. An effort is made to improve the mechanical and related heat-insulation properties of the products without significant change of present technology and price. This work studies the effect of metakaoline, as an alternative raw material to Portland cement, on final properties of autoclaved aerated concrete, especially the effect on the volume weight and compressive strength. Quantitative and qualitative mineralogical composition, especially the presence and the amount of Tobermorite and Xonotlite were observed by XRD and TG-DTA-EGA methods.

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Effects of Sintering Temperature on Structure and Electronic Properties of Mg0.2Zn0.8O:Al Ceramics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.320.236 ◽

2011 ◽

Vol 320 ◽

pp. 236-239

Author(s):

Hong Yan ◽

Hua Wang ◽

Shang Ju Zhou

Keyword(s):

Grain Size ◽

Electronic Properties ◽

Sintering Temperature ◽

Raw Materials ◽

High Density ◽

Homogeneous Structure ◽

Second Phase ◽

Pressureless Sintering ◽

Nano Scale ◽

Phase Nucleation

Mg0.2Zn0.8O:Al ceramics with high density using nano scale ZnO, MgO and Al2O3 powders as raw materials were obtained by pressureless sintering. The influence of presintering powder and sintering temperature on microstructure of Mg0.2Zn0.8O:Al ceramics were studied. The experiment indicated that presintering powder might decrease produce of the second phase nucleation. The grain size became gradually larger and density of ceramic became obviously higher from 1100°C to 1300°C, but the rising-trend became slower after 1300°C. The Mg0.2Zn0.8O:Al ceramics with high density and homogeneous structure can be made at 1300°C for

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Preparation of Light-Weight Ceramic Microsphere by Dolomite and Gangue

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.602-603.84 ◽

2014 ◽

Vol 602-603 ◽

pp. 84-87

Author(s):

Xiao Wei Cao ◽

Yan Gai Liu ◽

Zhao Hui Huang ◽

Ming Hao Fang ◽

Rui Long Wen

Keyword(s):

Bulk Density ◽

Ball Milling ◽

Apparent Density ◽

Sintering Temperature ◽

Raw Materials ◽

Coal Gangue ◽

Light Weight ◽

Phase Constitution ◽

Ceramic Microsphere

The ceramic microsphere was prepared by the ball milling and sintering using Dolomite and Coal Gangue as raw materials. The effects of ratio of raw materials, sintering temperature on bulk density and apparent density, phase constitution, microstructure of the ceramic microspheres were studied. The results indicated that the ratio of raw materials, sintering temperature has some effects on the bulk density and apparent density, phase constitution, microstructure of the ceramic microspheres. The bulk density and apparent density of the ceramic microspheres increased with sintering temperature rising. With the increasing of the ratio of dolomite, the bulk density of ceramic microspheres improved firstly and then dropped slightly, the apparent density of ceramic microspheres increased constantly. The bulk densities of the prepared ceramic microspheres were in the range of 0.570 g/cm3to 0.754 g/cm3, the apparent densities of the prepared ceramic microspheres were between 2.419 g/cm3and 2.661 g/cm3.

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Effect of starting materials and sintering temperature on microstructure and optical properties of Y2O3:Yb3+ 5 at% transparent ceramics

Journal of Advanced Ceramics ◽

10.1007/s40145-020-0416-3 ◽

2020 ◽

Author(s):

R. P. Yavetskiy ◽

A. E. Balabanov ◽

S. V. Parkhomenko ◽

O. S. Kryzhanovska ◽

A. G. Doroshenko ◽

...

Keyword(s):

Grain Size ◽

Optical Properties ◽

Sintering Temperature ◽

Raw Materials ◽

High Energy ◽

Reactive Sintering ◽

Average Grain Size ◽

Median Particle ◽

Energy Ball ◽

Sintering Method

Abstract Y2O3:Yb3+ 5 at% ceramics have been synthesized by the reactive sintering method using different commercial yttria powders (Alfa-Micro, Alfa-Nano, and ITO-V) as raw materials. It has been shown that all Y2O3 starting powders consist from agglomerates up to 5–7 µm in size which are formed from 25–60 nm primary particles. High-energy ball milling allows to significantly decreasing the median particle size D50 below 500 nm regardless of the commercial powders used. Sintering experiments indicate that powder mixtures fabricated from Alfa-Nano yttria powders have the highest sintering activity, while (Y0.86La0.09Yb0.05)2O3 ceramics sintered at 1750 °C for 10 h are characterized by the highest transmittance of about 45%. Y2O3:Yb3+ ceramics have been obtained by the reactive sintering at 1750–1825°C using Alfa-Nano Y2O3 powders and La2O3+ZrO2 as a complex sintering aid. The effects of the sintering temperature on densification processes, microstructure, and optical properties of Y2O3:Yb3+ 5 at% ceramics have been studied. It has been shown that Zr4+ ions decrease the grain growth of Y2O3:Yb3+ ceramics for sintering temperatures 1750–1775 °C. Further increasing the sintering temperature was accompanied by a sharp increase of the average grain size of ceramics referred to changes of structure and chemical composition of grain boundaries, as well as their mobility. It has been determined that the optimal sintering temperature to produce high-dense yttria ceramics with transmittance of 79%–83% and average grain size of 8 µm is 1800 °C. Finally, laser emission at ∼1030.7 nm with a slope efficiency of 10% was obtained with the most transparent Y2O3:Yb3+ 5 at% ceramics sintered.

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Anisotropy of Compressive Strength in Porous Alumina Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.604.153 ◽

2014 ◽

Vol 604 ◽

pp. 153-156 ◽

Cited By ~ 2

Author(s):

Ieva Zake-Tiluga ◽

Ruta Svinka ◽

Visvaldis Svinka

Keyword(s):

Compressive Strength ◽

Sintering Temperature ◽

Porous Alumina ◽

Slip Casting ◽

Mechanical Anisotropy ◽

Alumina Ceramics ◽

Casting Method ◽

Concrete Technology ◽

Pore Former ◽

Aerated Concrete

Anisotropy of the compressive strength was investigated in porous alumina based ceramics produced by slip casting method. Aluminium paste was used as pore former similarly as in the aerated concrete technology. Materials were sintered at 1650°C and 1750°C. The apparent porosity of the investigated materials was in the range of 54±1% to 60±2%. The compressive strength of the samples in the directions parallel and perpendicular to the sample expansion direction was in the range from 3.8±0.3 to 13.0±1.1 MPa and from 6.4±1.3 to 27.0±1.1 MPa, respectively. The mechanical anisotropy was related with the flattening of the introduced pores. The level of mechanical anisotropy was affected by the initial composition of the slurry and sintering temperature.

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Pressureless Sintering of YIG Ceramics from Coprecipitated Nanopowders

Magnetochemistry ◽

10.3390/magnetochemistry7050056 ◽

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+.

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

Crystals ◽

10.3390/cryst11040422 ◽

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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