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

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

Preparation and Electrical Property of Calcia Stabilized Zirconia Ceramics

2014 ◽  
Vol 616 ◽  
pp. 157-165 ◽  
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.

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+.

Preparation and Investigation on Properties of the MgTiO3-CaTiO3 Microwave Ceramic Materials

2014 ◽  
Vol 997 ◽  
pp. 419-423 ◽  
Author(s):  
Li Dong ◽  
Gui Xia Dong ◽  
Yuan Yuan Li ◽  
Xi Zhang
Keyword(s):  
Dielectric Constant ◽  
Sintering Temperature ◽  
Ceramic Materials ◽  
Volume Density ◽  
Second Phase ◽  
Pressureless Sintering ◽  
Solid Reaction ◽  
Reaction Method ◽  
Microwave Ceramic ◽  
Sintering Method

The MgTiO3 and CaTiO3 powders were synthesized by solid reaction method, and MgTiO3-CaTiO3 ceramic was prepared using pressureless sintering method. The experiment prepared MgTiO3-CaTiO3 ceramics with high compactness and stable permittivity by the way of changing the mole ratio of MgTiO3 and CaTiO3 to investigate the effect of CaTiO3 on the performances of MgTiO3-CaTiO3 ceramics. The results show that Mg2TiO4 formed as second phase during sintering. Volume density and dielectric constant of MgTiO3-CaTiO3 ceramics with 10%mol CaTiO3 reach maximum of 3.612g/cm3 and 17.8, respectively, under 1460°C sintering temperature. And for the MgTiO3-CaTiO3 ceramics with 5%mol CaTiO3 the maximum values which are 3.5g/cm3 and 16.6, respectively, appear under 1510°C sintering temperature.

Preparation of the System of BaO-MgO-Al2O3-TiO2 Acid-Resistant Fracturing Proppants

2011 ◽  
Vol 399-401 ◽  
pp. 855-859
Author(s):  
Ting Ting Wu ◽  
Bo Lin Wu
Keyword(s):  
Sintering Temperature ◽  
Raw Materials ◽  
Acid Resistance ◽  
Pressureless Sintering ◽  
Alumina Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Solubility ◽  
Resistance Performance ◽  
Scanning Electron

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.

Effect of Nano-Al2O3 Addition on the Densification of YSZ Electrolytes

2009 ◽  
Vol 6 ◽  
pp. 115-122 ◽  
Author(s):  
Dachamir Hotza ◽  
Adrian Leo ◽  
Jaka Sunarso ◽  
João C. Diniz da Costa
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Sintered Density ◽  
Sintering Temperature ◽  
Phase Segregation ◽  
Phase Evolution ◽  
Second Phase ◽  
Suspension Particle ◽  
Powder Suspension ◽  
Ysz Electrolyte

This work investigates the effect of nanosized Al2O3 addition on the sinterability of YSZ electrolyte. (1−x)YSZ + Al2O3 ceramics with compositions x = 0 to 0.01 were prepared by the conventional mixed oxide route from a commercial powder suspension (particle size <50 nm), and sintered at 1200 to 1500°C for 2 hours in air. Densification, phase evolution, and microstructure were characterized by SEM/EDS and XRD. An improvement in sintered density was observed for the samples with 0.2 to 0.5 mol% Al2O3, though depending on the sintering temperature. Only cubic zirconia was detected as crystalline phase, although XRD features suggested chemical interactions depending upon the amount of Al2O3. The grain size of YSZ was homogeneous and no second phase segregation was detected in the tested range of incorporated nano-Al2O3 and sintering temperatures.

Microstructures and Mechanical Properties of Y2O3 Ceramics

2017 ◽  
Vol 726 ◽  
pp. 179-183
Author(s):  
Tong Yu Zhu ◽  
Jin Feng Xia
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Sintering Temperature ◽  
High Density ◽  
Average Grain Size ◽  
Basic Performance ◽  
Different Temperatures ◽  
Microstructures And Mechanical Properties

Currently, Y2O3 ceramics are widely used in various fields. The basic performance of Y2O3 ceramics were sintered temperatures are studied in this paper, their phase compositions and microstructure are studied with XRD and SEM. The mechanical properties of Y2O3 ceramics at different temperatures are studied. The sintering temperature of Y2O3 ceramic significantly affected the final grain size and density. It was found that a high density and fine average grain size of Y2O3ceramic can be simultaneously achieved when the sintering temperature was 1600°C. To determine the best sintering temperature, grain size, density, and mechanical properties were considered, and the most suitable sintering temperature was found to be 1600°C.

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

2006 ◽  
Vol 45 ◽  
pp. 2266-2271 ◽  
Author(s):  
R. Svinka ◽  
V. Svinka ◽  
G. Bula ◽  
T. Juettner ◽  
E. Palcevskis
Keyword(s):  
Grain Size ◽  
Pore Formation ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Major Influence ◽  
Light Weight ◽  
Concentrated Suspensions ◽  
Concrete Technology ◽  
High Temperature Materials ◽  
Aerated Concrete

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.

The Preparation and Properties of Alumina Ceramics through a Two-Step Pressureless Sintering Process

2018 ◽  
Vol 922 ◽  
pp. 47-54
Author(s):  
Chang Suo Yuan ◽  
Zi Jing Wang ◽  
Qiang Zhi ◽  
Ya Ming Zhang ◽  
Xu Dong Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Relative Density ◽  
High Purity ◽  
Dominant Factor ◽  
Second Phase ◽  
Pressureless Sintering ◽  
Sintering Process ◽  
Alumina Ceramics ◽  
Soaking Time

In this paper, a high-dense alumina ceramics were prepared through the two-step pressureless sintering process with high-purity alumina powder as raw materials and high-purity MgO as sintering aids. The effects of the sintering temperature in the first-step (T1) and the soaking time (t) in the second sintering step (T2) on the density, microstructure and mechanical properties of the alumina ceramics were studied. The results indicated that the relative density increased with the increase of T1 temperature whereas it increased and then decreased with the increase of MgO content. Higher T1 temperature and extended soaking time caused larger grain size, which accompanied with the Ostwald ripening of the grain and led to non-uniformity of grain size distribution. The addition of MgO was beneficial to the decrease in grain size due to pinning effect of the second phase. For samples with shorter soaking time, sintering with higher T1 temperature led to better mechanical properties because of its high density. However, for the long soaking time, all samples after sintering at different T1 temperature were fully-densified, so the grain size become to the dominant factor of strength, thus samples with lower T1 temperature exhibited better mechanical properties due to the refinement grain. Excessive addition of MgO resulted in defects, by which the strength increased firstly and then decreased slightly with the increased MgO content. For the samples with 2.5wt.% MgO, the optimum condition for the two-step pressureless sintering was T1=1450°C and T2=1400°C for 20h, and the obtained sample achieved the relative density of 96% and the strength of 507±32MPa.

Synthesis of Pr6O11 Doped Zinc Varistors by High-Energy Milling

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.

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
Keyword(s):  
Wear Rate ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Alumina Ceramic ◽  
Pressureless Sintering ◽  
Alumina Ceramics ◽  
X Ray Diffraction ◽  
Wear Resistant ◽  
X Ray ◽  
Ceramic Samples

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.

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