Evaluation of the properties of some kinds of zirconia-based structural ceramics

Structural ceramics are necessarily polycrystalline and their usefulness is largely determined by the interfaces between the grains. The relationship between the structure and chemistry of different interfaces and the micro-structure can be illustrated by reviewing studies of interfaces in a wide range of materials including such classical ceramics as Al2O3, the current “hightech” polyphase ceramics exemplified by ZrO2-toughened Al2O3, and the composite materials of the future. Using transmission electron microscopy is essential for a complete understanding, but limitations to its use must be recognized. Only by understanding the factors that control the behavior of these interfaces will it become possible to further extend the application of interface engineering.Structural ceramics are a group of materials that can be used for applications requiring their strength to persist at high temperatures or in conditions that would be particularly corrosive to alternative materials, which are usually metallic. Strength and strength-related properties such as toughness depend largely on the microstructural features of the processed material.The microstructure is defined by the morphology and size of the grains and the interfaces between these grains. If the grains are in intimate contact, then the interface is a grain boundary of the type familiar from studies of metals.

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Study on Dielectric and Ferroelectric Properties of Gd-Doped Sr2Bi4Ti5O18 Ceramics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.328-330.1131 ◽

2011 ◽

Vol 328-330 ◽

pp. 1131-1134

Author(s):

Qian Chen ◽

Zhi Jun Xu ◽

Rui Qing Chu ◽

Yong Liu ◽

Ming Li Chen ◽

...

Keyword(s):

Piezoelectric Properties ◽

Ferroelectric Properties ◽

Solid State Reaction Method ◽

Lead Free ◽

Structural Ceramics ◽

Conventional Solid State Reaction ◽

Reaction Method ◽

Maximum Value ◽

Pure Bismuth ◽

Ferroelectric And Piezoelectric Properties

Lead-free piezoelectric ceramics Sr2Bi4-xGdxTi5O18 were prepared by conventional solid-state reaction method. Pure bismuth layered structural ceramics with uniform gain size were obtained in all samples. The effect of Gd-doping on the dielectric, ferroelectric and piezoelectric properties of Sr2Bi4Ti5O18 ceramics were also investigated. It was found that that Gd3+ dopant gradually decreased the Curie temperature (Tc) with the lower dielectric loss (tand) of SBTi ceramics. In addition, Gd-doping with appropriate content improved the ferroelectric and piezoelectric properties of the SBTi ceramics. The piezoelectric constant (d33) of the Sr2Bi3.9Gd0.1Ti5O18 ceramic reached the maximum value, which is 22 pC/N. The results showed that the Sr2Bi4-xGdxTi5O18 ceramic was a promising lead-free piezoelectric material.

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Temperature dependence of hardness prediction for high-temperature structural ceramics and their composites

Nanotechnology Reviews ◽

10.1515/ntrev-2021-0041 ◽

2021 ◽

Vol 10 (1) ◽

pp. 586-595

Author(s):

Ruzhuan Wang ◽

Dingyu Li ◽

Weiguo Li

Keyword(s):

High Temperature ◽

Temperature Dependence ◽

Material Design ◽

Theoretical Models ◽

Ceramic Composites ◽

Basic Material ◽

Experimental Measurements ◽

Control Mechanisms ◽

Oxide Ceramics ◽

Structural Ceramics

Abstract Hardness is one of the important mechanical properties of high-temperature structural ceramics and their composites. In spite of the extensive use of the materials in high-temperature applications, there are few theoretical models for analyzing their temperature-dependent hardness. To fill this gap in the available literature, this work is focused on developing novel theoretical models for the temperature dependence of the hardness of the ceramics and their composites. The proposed model is just expressed in terms of some basic material parameters including Young’s modulus, melting points, and critical damage size corresponding to plastic deformation, which has no fitting parameters, thereby being simple for materials scientists and engineers to use in the material design. The model predictions for the temperature dependence of hardness of some oxide ceramics, non-oxide ceramics, ceramic–ceramic composites, diamond–ceramic composites, and ceramic-based cermet are presented, and excellent agreements with the experimental measurements are shown. Compared with the experimental measurements, the developed model can effectively save the cost when applied in the material design, which could be used to predict at any targeted temperature. Furthermore, the models could be used to determine the underlying control mechanisms of the temperature dependence of the hardness of the materials.

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