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<\/p>","protected":false},"excerpt":{"rendered":"The properties of alumina ceramics materials are mainly determined by their chemical bonds, crystal structure and crystal defects. From the perspective of crystal structure, the interatomic bonding force of ceramic materials is mainly ionic bond, covalent bond or ionic covalent mixed bond. These chemical bonds not only have high bonding strength, but also have directionality. Crystal defects (especially line defects and dislocations) can move in the crystal, and the critical shear stress required for the dislocation to move along the most closely aligned plane and direction is very small. The large amount of dislocation movement causes obvious slip phenomenon on the crystal plane and macro plastic deformation. The bonding strength of metal bonds does not change significantly before and after macro plastic deformation, but the ionic bonds and covalent bonds in ceramics are different. Due to the complex crystal structure and low symmetry of ceramics, when the dislocation moves along the slip surface, the crystal structure is difficult to recover (due to the destruction of the minimum energy state of positive and negative ion arrangement), which may lead to the destruction of atomic bonds and brittle fracture without plastic deformation. Due to different bonding bonds, the properties of metal and ceramic materials differ greatly. The melting point and hardness of ceramics may be several to ten times higher than that of metals with the same element. For example, the melting point of Al2O3 is about three times that of metal aluminum, while the hardness is more than 10 times higher than that of metal aluminum.<\/p>\n
Another characteristic of alumina ceramic material structure is the heterogeneity and complexity of microstructure. Metal materials are usually solidified from a fairly uniform metal melt, and then the microstructure of the material can be improved and homogenized by means of cold and hot processing. Metal materials do not contain or contain very few pores. However, ceramic materials are generally formed by powder forming and sintering, which inevitably has a certain number of pores. Although the powder with different composition and particle size is mixed by ball milling, it is still difficult to achieve a very uniform degree. In addition, there are often glass phases on the ceramic grain boundary which are different from the matrix composition and structure.<\/p>\n
The structural characteristics of ceramic materials determine the properties of materials, including mechanical, electrical, magnetic, acoustic, optical, thermal and other properties. Based on the structural characteristics of alumina ceramics, it is not difficult to understand why structural ceramics have high melting point, high strength, wear resistance, corrosion resistance and other basic properties, but there are fatal weaknesses such as brittleness, difficult processing, poor reliability and reproducibility. These weaknesses bring many difficulties to the engineering application of structural ceramics.<\/p>\n
<\/p>","protected":false},"excerpt":{"rendered":"
The properties of alumina ceramics materials are mainly determined by their chemical bonds, crystal structure and crystal defects. From the […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"footnotes":""},"categories":[6],"tags":[],"class_list":["post-332","post","type-post","status-publish","format-standard","hentry","category-alumina-knowledge"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/aluminaceramics.net\/el\/wp-json\/wp\/v2\/posts\/332","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/aluminaceramics.net\/el\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/aluminaceramics.net\/el\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/aluminaceramics.net\/el\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/aluminaceramics.net\/el\/wp-json\/wp\/v2\/comments?post=332"}],"version-history":[{"count":3,"href":"https:\/\/aluminaceramics.net\/el\/wp-json\/wp\/v2\/posts\/332\/revisions"}],"predecessor-version":[{"id":342,"href":"https:\/\/aluminaceramics.net\/el\/wp-json\/wp\/v2\/posts\/332\/revisions\/342"}],"wp:attachment":[{"href":"https:\/\/aluminaceramics.net\/el\/wp-json\/wp\/v2\/media?parent=332"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/aluminaceramics.net\/el\/wp-json\/wp\/v2\/categories?post=332"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/aluminaceramics.net\/el\/wp-json\/wp\/v2\/tags?post=332"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}