{"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\/da\/undersogelse-af-aeldning-af-talk-keramik-transformation-mellem-magnesium-metasilikat-krystaller\/","title":{"rendered":"Unders\u00f8gelse af \u00e6ldning af talk-keramik - Transformation mellem magnesiummetasilikatkrystaller"},"content":{"rendered":"<p>Der er udf\u00f8rt omfattende forskning i omdannelsen mellem krystalformer af magnesiummetasilikat. P\u00e5 nuv\u00e6rende tidspunkt kan man dog ikke sige, at der er en fuldst\u00e6ndig samlet og sikker forst\u00e5else af dette sp\u00f8rgsm\u00e5l. De resultater, der blev opn\u00e5et af J.F. Sarver et al. i 1962, kan dog bruges som MgSiO<sub>3<\/sub> ved temperaturer under 1400 \u2103 grundl\u00e6ggende oplysninger om lovene for krystalomdannelse. Saville et al. leverede MgSiO<sub>3<\/sub> T-P-fasediagrammet viser, at den vigtigste krystallinske fase, der dannes under fyring af talkumkeramik, er original enstatit, som afk\u00f8les til 1042 \u2103 (m\u00e5lt ved slukningsmetode). Resultatet opn\u00e5et ved r\u00f8ntgendiffraktionsmetode ved h\u00f8j temperatur er 1035 \u2103, og der er en tendens til at omdanne til enstatit mellem 865 \u2103, og under 865 \u2103 er der en tendens til at omdanne til metastabil krystallinsk clinopyroxen. Under 865 \u00b0C kan metastabil krystallinsk clinopyroxen eksistere i lang tid og vil ikke blive omdannet til termodynamisk stabil clinopyroxen. \u00c6ldning eller pulverisering af talk-keramik skyldes omdannelse af h\u00f8jtemperaturkrystallinsk fase prim\u00e6r enstatit til enstatit eller clinopyroxen under afk\u00f8ling, placering og brug.<\/p>\n<p>If\u00f8lge den teoretiske t\u00e6thed beregnet ud fra gitterparametre kan det ses, at omdannelsen af prim\u00e6r enstatit til clinopyroxen ved stuetemperatur ledsages af en volumen\u00e6ndring p\u00e5 ca. 2,8%, og volumen\u00e6ndringen, n\u00e5r prim\u00e6r enstatit omdannes til enstatit, er endnu st\u00f8rre. Hvis man analyserer ud fra gitterparametre, da volumen\u00e6ndringen er det samlede resultat af krystal c-akseforkortelse og b-akseforl\u00e6ngelse, er virkningen af kornl\u00e6ngde\u00e6ndring under omdannelsesprocessen uundg\u00e5eligt mere fremtr\u00e6dende end det, der afspejles af volumen\u00e6ndringsv\u00e6rdien. Den store stamme, der ledsager transformationsprocessen, genererer uundg\u00e5eligt stor stress, og effekten af denne fase\u00e6ndringsstress er den mere direkte \u00e5rsag til \u00e6ldning eller pulverisering af talkumkina. Original enstatit er den vigtigste krystallinske fase af talkum porcel\u00e6n, og den fremragende ydeevne af talkum keramik er direkte relateret til den oprindelige enstatit. P\u00e5 den m\u00e5de bliver l\u00f8sningen p\u00e5 problemet med \u00e6ldning eller pulverisering af talkum porcel\u00e6n problemet med, hvordan man stabiliserer den oprindelige enstatit, s\u00e5 den ikke omdannes til enstatit eller clinopyroxen under afk\u00f8ling, placering og brug.<\/p>","protected":false},"excerpt":{"rendered":"<p>Der er udf\u00f8rt omfattende forskning i omdannelsen mellem krystalformer af magnesiummetasilikat. P\u00e5 nuv\u00e6rende tidspunkt kan det dog ikke [...]<\/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\/da\/wp-json\/wp\/v2\/posts\/19","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/artehistoria.net\/da\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/artehistoria.net\/da\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/artehistoria.net\/da\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/artehistoria.net\/da\/wp-json\/wp\/v2\/comments?post=19"}],"version-history":[{"count":4,"href":"https:\/\/artehistoria.net\/da\/wp-json\/wp\/v2\/posts\/19\/revisions"}],"predecessor-version":[{"id":23,"href":"https:\/\/artehistoria.net\/da\/wp-json\/wp\/v2\/posts\/19\/revisions\/23"}],"wp:attachment":[{"href":"https:\/\/artehistoria.net\/da\/wp-json\/wp\/v2\/media?parent=19"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/artehistoria.net\/da\/wp-json\/wp\/v2\/categories?post=19"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/artehistoria.net\/da\/wp-json\/wp\/v2\/tags?post=19"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}