{"id":19,"date":"2023-11-07T13:59:53","date_gmt":"2023-11-07T05:59:53","guid":{"rendered":"https:\/\/artehistoria.net\/?p=19"},"modified":"2023-11-07T14:17:24","modified_gmt":"2023-11-07T06:17:24","slug":"study-on-aging-of-talc-ceramics-transformation-between-magnesium-metasilicate-crystals","status":"publish","type":"post","link":"https:\/\/artehistoria.net\/fr\/etude-du-vieillissement-des-ceramiques-de-talc-transformation-entre-cristaux-de-metasilicate-de-magnesium\/","title":{"rendered":"Etude sur le vieillissement des c\u00e9ramiques de talc - Transformation entre cristaux de m\u00e9tasilicate de magn\u00e9sium"},"content":{"rendered":"<p>Des recherches approfondies ont \u00e9t\u00e9 men\u00e9es sur la conversion entre les formes cristallines du m\u00e9tasilicate de magn\u00e9sium. Cependant, \u00e0 l'heure actuelle, on ne peut pas consid\u00e9rer qu'il existe une compr\u00e9hension compl\u00e8tement unifi\u00e9e et d\u00e9finitive de cette question. Toutefois, les r\u00e9sultats obtenus par J.F. Sarver et al. en 1962 peuvent \u00eatre utilis\u00e9s comme base pour la d\u00e9termination de la forme cristalline du MgSiO<sub>3<\/sub> \u00e0 des temp\u00e9ratures inf\u00e9rieures \u00e0 1400 \u2103 des informations de base sur les lois de la transformation cristalline. Saville et al. ont fourni des donn\u00e9es sur le MgSiO<sub>3<\/sub> Le diagramme de phase T-P montre que la principale phase cristalline form\u00e9e pendant la cuisson des c\u00e9ramiques de talc est l'enstatite d'origine, qui est refroidie \u00e0 1042 \u2103 (mesur\u00e9e par la m\u00e9thode de trempe). Le r\u00e9sultat obtenu par la m\u00e9thode de diffraction des rayons X \u00e0 haute temp\u00e9rature est de 1035 \u2103, et il y a une tendance \u00e0 se transformer en enstatite entre 865 \u2103, et en dessous de 865 \u2103, il y a une tendance \u00e0 se transformer en clinopyrox\u00e8ne cristallin m\u00e9tastable. Au-dessous de 865 \u2103, le clinopyrox\u00e8ne cristallin m\u00e9tastable peut exister pendant longtemps et ne sera pas converti en clinopyrox\u00e8ne thermodynamiquement stable. Le vieillissement ou la pulv\u00e9risation des c\u00e9ramiques de talc est caus\u00e9 par la transformation de la phase cristalline primaire de l'enstatite \u00e0 haute temp\u00e9rature en enstatite ou en clinopyrox\u00e8ne pendant le refroidissement, la mise en place et l'utilisation.<\/p>\n<p>D'apr\u00e8s la densit\u00e9 th\u00e9orique calcul\u00e9e \u00e0 partir des param\u00e8tres de r\u00e9seau, on peut constater que la conversion de l'enstatite primaire en clinopyrox\u00e8ne \u00e0 temp\u00e9rature ambiante s'accompagne d'un changement de volume d'environ 2,8%, et que le changement de volume lorsque l'enstatite primaire est convertie en enstatite est encore plus important. Si on l'analyse \u00e0 partir des param\u00e8tres du r\u00e9seau, comme le changement de volume est le r\u00e9sultat total du raccourcissement de l'axe c et de l'allongement de l'axe b du cristal, l'impact du changement de la longueur des grains pendant le processus de conversion est in\u00e9vitablement plus important que celui refl\u00e9t\u00e9 par la valeur du changement de volume. L'importante d\u00e9formation qui accompagne le processus de transformation g\u00e9n\u00e8re in\u00e9vitablement une forte contrainte, et l'effet de cette contrainte de changement de phase est la raison la plus directe du vieillissement ou de la pulv\u00e9risation du talc de chine. L'enstatite d'origine est la principale phase cristalline du talc, et l'excellente performance des c\u00e9ramiques de talc est directement li\u00e9e \u00e0 l'enstatite d'origine. Ainsi, la r\u00e9solution du probl\u00e8me du vieillissement ou de la pulv\u00e9risation du talc devient le probl\u00e8me de la stabilisation de l'enstatite d'origine afin qu'elle ne se transforme pas en enstatite ou en clinopyrox\u00e8ne pendant le refroidissement, la mise en place et l'utilisation.<\/p>","protected":false},"excerpt":{"rendered":"<p>Des recherches approfondies ont \u00e9t\u00e9 men\u00e9es sur la conversion entre les formes cristallines du m\u00e9tasilicate de magn\u00e9sium. Cependant, \u00e0 l'heure actuelle, il n'est pas possible de [...]<\/p>","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":"","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":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","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":[2],"tags":[],"class_list":["post-19","post","type-post","status-publish","format-standard","hentry","category-news"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/artehistoria.net\/fr\/wp-json\/wp\/v2\/posts\/19","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/artehistoria.net\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/artehistoria.net\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/artehistoria.net\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/artehistoria.net\/fr\/wp-json\/wp\/v2\/comments?post=19"}],"version-history":[{"count":4,"href":"https:\/\/artehistoria.net\/fr\/wp-json\/wp\/v2\/posts\/19\/revisions"}],"predecessor-version":[{"id":23,"href":"https:\/\/artehistoria.net\/fr\/wp-json\/wp\/v2\/posts\/19\/revisions\/23"}],"wp:attachment":[{"href":"https:\/\/artehistoria.net\/fr\/wp-json\/wp\/v2\/media?parent=19"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/artehistoria.net\/fr\/wp-json\/wp\/v2\/categories?post=19"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/artehistoria.net\/fr\/wp-json\/wp\/v2\/tags?post=19"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}