scholarly journals Grain Size Dependence of Thermal Shock Resistance in KZr2(PO4)3 Ceramic

1994 ◽  
Vol 102 (1188) ◽  
pp. 718-721 ◽  
Author(s):  
Naruhito KATAGIRI ◽  
Yasuhisa HATTORI ◽  
Toshitaka OTA ◽  
Iwao YAMAI
Keyword(s):  
Grain Size ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Size Dependence ◽  
Shock Resistance

Grain-Size Dependence of Thermal-Shock Resistance of Yttria-Doped Tetragonal Zirconia Polycrystals

1990 ◽  
Vol 73 (8) ◽  
pp. 2523-2525 ◽  
Author(s):  
Masayuki Ishitsuka ◽  
Tsugio Sato ◽  
Tadashi Endo ◽  
Masahiko Shimada ◽  
Hideo Ohno ◽  
...  
Keyword(s):  
Grain Size ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Size Dependence ◽  
Tetragonal Zirconia ◽  
Shock Resistance

Optimizing Performance of Magnesia-Spinel Brick Used at Cement Rotary Kiln

2011 ◽  
Vol 250-253 ◽  
pp. 588-594 ◽  
Author(s):  
Dong Wang ◽  
Yong Li ◽  
Yang Li ◽  
Rui Li ◽  
Yue Li
Keyword(s):  
Grain Size ◽  
Thermal Shock ◽  
Rotary Kiln ◽  
Thermal Shock Resistance ◽  
Raw Material ◽  
Crushing Strength ◽  
Magnesia Spinel ◽  
Cold Crushing Strength ◽  
Comprehensive Performance ◽  
Shock Resistance

Using high pure magnesia and magnesia-spinel as the main raw material, keeping the same quantity of spinel, specimens were made with different spinel size distribution (≤0.044mm, 1-0mm, 2-1mm, 3-2mm and 3-1mm). Dextrin and brine are the binder. Specimens were dried at the temperature of 110°C for 24 hours, sintered at the temperature of 1680°C holding 8 hours in a tunnel kiln. The properties and microstructure of the specimens were analyzed. The results are shown that the addition of spinel with grain size of 3-1mm improves sintering of magnesia-spinel brick, with the thermal shock resistance reaching 18 cycles, the cold crushing strength reaching 54 MPa, improving the comprehensive performance of the magnesia-spinel brick.

Effect of grain size on thermal shock resistance of Al2O3–TiC ceramics

2005 ◽  
Vol 31 (1) ◽  
pp. 33-38 ◽  
Author(s):  
X.Q. You ◽  
T.Z. Si ◽  
N. Liu ◽  
P.P. Ren ◽  
Y.D. Xu ◽  
...  
Keyword(s):  
Grain Size ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Shock Resistance

scholarly journals Numerical Study of Thermal Shock Damage Mechanism of Polycrystalline Ceramics

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhenyuan Gong ◽  
Kang Guan ◽  
Pinggen Rao ◽  
Qingfeng Zeng ◽  
Jiantao Liu ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Critical Stress ◽  
Crack Nucleation ◽  
Damage Mechanism ◽  
Shock Resistance ◽  
Grain Boundary Fracture ◽  
Boundary Fracture

A dual-scale model is proposed to study the effect of microstructure parameters (grain size and grain boundary fracture energy) on the thermal shock damage mechanism on an example of alumina. At microscale, representative volume element (RVE) models generated by Voronoi tessellation are simulated to obtain the mechanical parameters for macro models. At macroscale, a coupled thermomechanical model based on the finite–discrete element method (FDEM) is applied to simulate the crack nucleation and propagation. Energy dissipation (ALLDMD) is introduced to investigate the thermal shock cracking mechanism by combining crack patterns and crack density, which indicates that decreasing grain size and increasing grain boundary fracture energy have a positive effect on thermal shock resistance. The proposed models not only predict the critical stress temperature which is well consistent to the theoretical thermal shock resistance factor, but also quantify the two previously unconsidered stages (crack nucleation and crack instability stage). Our models suggest the crack nucleation and instability will not occur immediately when the model reaches critical stress, but the models can sustain for higher temperature difference. The thermal shock damage mechanism and the influence of microstructural parameters on thermal shock resistance have also been discussed in detail.

Preliminary Electron Microscopic Study of Thermal-Shock-Resistant Ceramic-Metal Composites

1981 ◽  
Vol 39 ◽  
pp. 140-141
Author(s):  
R. J. Lauf ◽  
C. S. Morgan
Keyword(s):  
Grain Size ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Hot Water ◽  
Alumina Powder ◽  
Air Cooling ◽  
Metal Composites ◽  
Electrical Insulator ◽  
Platinum Particles ◽  
Shock Resistance

Ceramic-metal composites, or cermets, are used for a variety of applications. In general, the ceramic phase provides hardness or wear resistance while a continuous metal phase acts as a binder and provides toughness. The alumina-based cermets described here are unique in that the metallic phase (platinum) is discontinuous and constitutes only about 1 to 2 vol % of the structure. This material was developed to serve as a high-temperature electrical insulator under conditions of severe thermal shock. Because of the small grain sizes involved, electron microscopy was used to study the relation between properties and process variables as well as to better understand the mechanism of thermal shock resistance.Platinum was intimately mixed with alumina powder by precipitation from a PtCl4 solution followed by drying. The resulting powder mixture was hot-pressed in a graphite die at 1610°C for 15 min under 69 MPa (10,000 psi) pressure. Cermets produced from Alcoa A-17 alumina powder had a final grain size of 15 ± 4 μm, while Fisher Scientific reagent-grade alumina resulted in a grain size of 4 ± 1 μm. The platinum particles ranged from 0.2 to 1.0 μm in diameter. Thermal shock resistance was tested by heating the cermet to 520°C and quenching in hot water. Cermets that were gastight after 15 quench cycles were considered acceptable. Thermal shock resistance was improved by heating the as-pressed pellet to 1630°C and air cooling.

Fracture behavior of Al2O3/SiC-platelet composites

1996 ◽  
Vol 11 (10) ◽  
pp. 2528-2535 ◽  
Author(s):  
M. Belmonte ◽  
J. S. Moya ◽  
P. Miranzo ◽  
D. Nguyen ◽  
J. Dubois ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Grain Size ◽  
Mechanical Behavior ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Impurity Content ◽  
High Viscosity ◽  
Large Matrix ◽  
Alumina Composites ◽  
Shock Resistance

Mechanical behavior of hot-pressed SiC platelet reinforced alumina composites has been analyzed as a function of SiC platelet content for two different alumina matrix powders. Fracture toughness and flexural strength at temperatures ranging from 25 to 1200 °C, R-curve behavior, and thermal shock resistance have been determined. Small differences in the impurity content of the starting Al2O3 powders strongly determine the microstructure and the mechanical behavior of Al2O3/SiC-platelet composites. Low alkali content alumina led to composites with large matrix grain size which presented spontaneous microcracking. At high temperature, a high viscosity liquid phase is formed that shields cracks enhancing mechanical properties and R-curve behavior. A small amount of impurities reduced Al2O3 matrix grain size and avoided spontaneous microcracking. Enhanced fracture toughness (up to 30%) at room temperature, R-curve behavior, and thermal shock resistance were achieved for these materials.

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