{"id":103306,"date":"2024-07-17T15:47:43","date_gmt":"2024-07-17T13:47:43","guid":{"rendered":"https:\/\/www.linseis.com\/sem-categoria\/determinacao-da-densidade-cte\/"},"modified":"2026-01-12T09:43:16","modified_gmt":"2026-01-12T08:43:16","slug":"determinacao-da-densidade-cte","status":"publish","type":"post","link":"https:\/\/www.linseis.com\/pt-pt\/conhecimentos\/determinacao-da-densidade-cte\/","title":{"rendered":"Determina\u00e7\u00e3o da densidade CTE"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"103306\" class=\"elementor elementor-103306 elementor-9942\" data-elementor-post-type=\"post\">\n\t\t\t\t<div class=\"elementor-element elementor-element-9eb8745 e-flex e-con-boxed e-con e-parent\" data-id=\"9eb8745\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-fb52706 elementor-toc--minimized-on-tablet elementor-invisible elementor-widget elementor-widget-table-of-contents\" data-id=\"fb52706\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;headings_by_tags&quot;:[&quot;h2&quot;],&quot;exclude_headings_by_selector&quot;:[],&quot;_animation&quot;:&quot;fadeInUp&quot;,&quot;no_headings_message&quot;:&quot;No headings were found on this page.&quot;,&quot;marker_view&quot;:&quot;numbers&quot;,&quot;minimize_box&quot;:&quot;yes&quot;,&quot;minimized_on&quot;:&quot;tablet&quot;,&quot;hierarchical_view&quot;:&quot;yes&quot;,&quot;min_height&quot;:{&quot;unit&quot;:&quot;px&quot;,&quot;size&quot;:&quot;&quot;,&quot;sizes&quot;:[]},&quot;min_height_tablet&quot;:{&quot;unit&quot;:&quot;px&quot;,&quot;size&quot;:&quot;&quot;,&quot;sizes&quot;:[]},&quot;min_height_mobile&quot;:{&quot;unit&quot;:&quot;px&quot;,&quot;size&quot;:&quot;&quot;,&quot;sizes&quot;:[]}}\" data-widget_type=\"table-of-contents.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<div class=\"elementor-toc__header\">\n\t\t\t\t\t\t<h4 class=\"elementor-toc__header-title\">\n\t\t\t\t\u00cdndice\t\t\t<\/h4>\n\t\t\t\t\t\t\t\t\t\t<div class=\"elementor-toc__toggle-button elementor-toc__toggle-button--expand\" role=\"button\" tabindex=\"0\" aria-controls=\"elementor-toc__fb52706\" aria-expanded=\"true\" aria-label=\"Open table of contents\"><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-down\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M207.029 381.476L12.686 187.132c-9.373-9.373-9.373-24.569 0-33.941l22.667-22.667c9.357-9.357 24.522-9.375 33.901-.04L224 284.505l154.745-154.021c9.379-9.335 24.544-9.317 33.901.04l22.667 22.667c9.373 9.373 9.373 24.569 0 33.941L240.971 381.476c-9.373 9.372-24.569 9.372-33.942 0z\"><\/path><\/svg><\/div>\n\t\t\t\t<div class=\"elementor-toc__toggle-button elementor-toc__toggle-button--collapse\" role=\"button\" tabindex=\"0\" aria-controls=\"elementor-toc__fb52706\" aria-expanded=\"true\" aria-label=\"Close table of contents\"><svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-chevron-up\" viewBox=\"0 0 448 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M240.971 130.524l194.343 194.343c9.373 9.373 9.373 24.569 0 33.941l-22.667 22.667c-9.357 9.357-24.522 9.375-33.901.04L224 227.495 69.255 381.516c-9.379 9.335-24.544 9.317-33.901-.04l-22.667-22.667c-9.373-9.373-9.373-24.569 0-33.941L207.03 130.525c9.372-9.373 24.568-9.373 33.941-.001z\"><\/path><\/svg><\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<div id=\"elementor-toc__fb52706\" class=\"elementor-toc__body\">\n\t\t\t<div class=\"elementor-toc__spinner-container\">\n\t\t\t\t<svg class=\"elementor-toc__spinner eicon-animation-spin e-font-icon-svg e-eicon-loading\" aria-hidden=\"true\" viewBox=\"0 0 1000 1000\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M500 975V858C696 858 858 696 858 500S696 142 500 142 142 304 142 500H25C25 237 238 25 500 25S975 237 975 500 763 975 500 975Z\"><\/path><\/svg>\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-8a9139e elementor-invisible elementor-widget elementor-widget-heading\" data-id=\"8a9139e\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Expans\u00e3o t\u00e9rmica e densidade<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-cbf12b4 e-con-full e-flex e-con e-child\" data-id=\"cbf12b4\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div class=\"elementor-element elementor-element-a5b4d15 e-con-full e-flex e-con e-child\" data-id=\"a5b4d15\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-6605541 elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"6605541\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>A dilata\u00e7\u00e3o t\u00e9rmica dos materiais pode causar grandes preju\u00edzos econ\u00f3micos. Na ind\u00fastria da constru\u00e7\u00e3o, por exemplo, devem ser previstas juntas de dilata\u00e7\u00e3o para compensar as altera\u00e7\u00f5es de comprimento devidas \u00e0s <g id=\"gid_0\">varia\u00e7\u00f5es de temperatura<\/g>. Al\u00e9m disso, <strong>os coeficientes<\/strong> de dilata\u00e7\u00e3o dos <strong>materiais<\/strong> <strong>em contacto<\/strong> uns <strong>com os<\/strong> outros devem ser harmonizados. Se os coeficientes de dilata\u00e7\u00e3o de um corpo cer\u00e2mico e de um esmalte diferirem demasiado, surgem as chamadas <strong>&#8220;fissuras em teia de aranha&#8221;,<\/strong> que podem ser frequentemente observadas em pratos de porcelana antigos.   <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-7396df6 e-con-full e-flex e-con e-child\" data-id=\"7396df6\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-fa6511d elementor-invisible elementor-widget elementor-widget-image\" data-id=\"fa6511d\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"800\" height=\"534\" src=\"https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/iStock-873866046-min-2048x1367-2-1024x684.jpg\" class=\"attachment-large size-large wp-image-33468\" alt=\"\" srcset=\"https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/iStock-873866046-min-2048x1367-2-1024x684.jpg 1024w, https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/iStock-873866046-min-2048x1367-2-300x200.jpg 300w, https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/iStock-873866046-min-2048x1367-2-768x513.jpg 768w, https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/iStock-873866046-min-2048x1367-2-1536x1025.jpg 1536w, https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/iStock-873866046-min-2048x1367-2.jpg 2048w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-59f6594 elementor-widget elementor-widget-spacer\" data-id=\"59f6594\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-8b852c8 elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"8b852c8\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>A expans\u00e3o ocorre em todas as direc\u00e7\u00f5es espaciais, de modo que a densidade muda \u00e0 medida que a massa permanece constante. <strong>A expans\u00e3o de materiais anisotr\u00f3picos \u00e9 dependente da dire\u00e7\u00e3o<\/strong>, pelo que a dire\u00e7\u00e3o da expans\u00e3o deve ser especificada. Para determinar a densidade ou o <strong>coeficiente de expans\u00e3o do volume<\/strong>, todas as direc\u00e7\u00f5es espaciais devem ser tidas em conta. <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-72ccd75 elementor-invisible elementor-widget elementor-widget-heading\" data-id=\"72ccd75\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Defini\u00e7\u00e3o de expans\u00e3o t\u00e9rmica<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-40545f1 elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"40545f1\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>O <strong><a href=\"https:\/\/www.linseis.com\/messgroessen\/laengenausdehnungskoeffizient\/\">coeficiente de expans\u00e3o t\u00e9rmica\u03b1<\/a>, tamb\u00e9m<\/strong> conhecido como <strong>CTE<\/strong>, \u00e9 definido como a mudan\u00e7a relativa no comprimento quando a temperatura muda em um Kelvin:<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-5ba0d8c elementor-widget__width-initial elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"5ba0d8c\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>\u03b1= \u2206L\/(L0 *\u2206T)<br>com:<br>\u2206L: Varia\u00e7\u00e3o do comprimento [m]<br>L0: Comprimento inicial [m]<br>\u2206T: Varia\u00e7\u00e3o da temperatura [K]<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-f333ecd elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"f333ecd\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>resulta na unidade K-1 (&#8220;por Kelvin&#8221;) para <strong>\u03b1<\/strong>. Depende da temperatura e, por conseguinte, varia, mas muitas vezes apenas em pequena escala, consoante a gama de temperaturas considerada. A sua ordem de grandeza \u00e9 normalmente 10-6 K-1, pelo que \u00e9 frequentemente indicada em &#8220;ppm K-1&#8221;.  <\/p><p>Os materiais com <strong>coeficientes<\/strong> de dilata\u00e7\u00e3o <strong>baixos<\/strong> s\u00e3o, por exemplo, o vidro de quartzo e o metal INVAR, que t\u00eam um coeficiente de dilata\u00e7\u00e3o inferior a 1 ppm K-1. Os pol\u00edmeros t\u00eam os coeficientes de expans\u00e3o mais elevados (at\u00e9 cerca de 200 ppm K-1).<strong> Dependendo da gama de temperaturas<\/strong>, alguns materiais apresentam<strong> expans\u00f5es negativas<\/strong>.  <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-77b5557 elementor-invisible elementor-widget elementor-widget-heading\" data-id=\"77b5557\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Transforma\u00e7\u00f5es de fase<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-a02ac69 elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"a02ac69\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>Os coeficientes de dilata\u00e7\u00e3o das diferentes fases de um mesmo material s\u00e3o diferentes. Por exemplo, os coeficientes de expans\u00e3o dos pol\u00edmeros acima da <a href=\"https:\/\/www.linseis.com\/pt-pt\/?p=103212\">\n  <strong>temperatura de transi\u00e7\u00e3o v\u00edtrea<\/strong>\n<\/a> s\u00e3o maiores do que abaixo. <\/p><p>Outro exemplo bem conhecido s\u00e3o as <strong>transforma\u00e7\u00f5es de fase do ferro elementar:<\/strong> at\u00e9 906 \u00b0C, a estrutura cristalina c\u00fabica centrada no corpo \u00e9 est\u00e1vel (\u03b1-ferro), de 906 \u00b0C a 1401 \u00b0C a estrutura c\u00fabica mais densa (\u03b2-ferro) e acima de 1539 \u00b0C a estrutura c\u00fabica centrada no corpo (\u03b4-ferro). Como o preenchimento do espa\u00e7o do empacotamento c\u00fabico mais denso (74%) \u00e9 maior do que o do empacotamento c\u00fabico centrado no corpo (68%), h\u00e1 saltos na densidade e, portanto, tamb\u00e9m no comprimento durante as transforma\u00e7\u00f5es de fase. Estes s\u00e3o utilizados para detetar transi\u00e7\u00f5es de fase em ligas de ferro:  <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-50997b7 elementor-widget__width-initial elementor-invisible elementor-widget elementor-widget-image\" data-id=\"50997b7\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" width=\"800\" height=\"515\" src=\"https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/Applikation-CTE-Dichte-2048x1317-1-1024x659.jpg\" class=\"attachment-large size-large wp-image-31827\" alt=\"\" srcset=\"https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/Applikation-CTE-Dichte-2048x1317-1-1024x659.jpg 1024w, https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/Applikation-CTE-Dichte-2048x1317-1-300x193.jpg 300w, https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/Applikation-CTE-Dichte-2048x1317-1-768x494.jpg 768w, https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/Applikation-CTE-Dichte-2048x1317-1-1536x988.jpg 1536w, https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/Applikation-CTE-Dichte-2048x1317-1.jpg 2048w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-9b6a47e elementor-invisible elementor-widget elementor-widget-heading\" data-id=\"9b6a47e\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Medi\u00e7\u00e3o do coeficiente de expans\u00e3o<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-f3a894e elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"f3a894e\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\tO m\u00e9todo de medi\u00e7\u00e3o a selecionar depende do estado agregado da amostra, da dimens\u00e3o do coeficiente de dilata\u00e7\u00e3o da amostra a medir e da gama de temperaturas a considerar. As propriedades mec\u00e2nicas da amostra tamb\u00e9m devem ser tidas em conta na prepara\u00e7\u00e3o de amostras adequadas e, por conseguinte, na sele\u00e7\u00e3o do m\u00e9todo de medi\u00e7\u00e3o. \t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-c9c0525 elementor-invisible elementor-widget elementor-widget-heading\" data-id=\"c9c0525\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">L\u00edquidos<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-07f3c6a elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"07f3c6a\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>A expans\u00e3o ou densidade dos l\u00edquidos \u00e9 geralmente determinada utilizando picn\u00f3metros. Um volume constante da amostra \u00e9 temperado e a massa \u00e9 determinada. Os l\u00edquidos expandem-se normalmente com o aumento da temperatura.    <strong>Uma exce\u00e7\u00e3o bem conhecida \u00e9 a \u00e1gua, que tem a sua densidade m\u00e1xima a 4 \u00b0C (&#8220;anomalia da \u00e1gua&#8221;).<\/strong><\/p><p>O chamado <strong>m\u00e9todo do tubo em U oscilante<\/strong> tamb\u00e9m \u00e9 utilizado. Neste caso, a densidade \u00e9 calculada medindo a frequ\u00eancia natural de um tubo em U oscilante cheio com o l\u00edquido a analisar.<br>Os l\u00edquidos tamb\u00e9m podem ser medidos utilizando recipientes adequados para l\u00edquidos num dilat\u00f3metro de haste. Deve ter-se o cuidado de assegurar que n\u00e3o h\u00e1 fuga de gases do l\u00edquido e que os gases que se escapam tamb\u00e9m saem do recipiente, embora a amostra l\u00edquida n\u00e3o deva escapar.  <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-6132160 elementor-invisible elementor-widget elementor-widget-heading\" data-id=\"6132160\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Estado s\u00f3lido<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-bca70af elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"bca70af\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>Os s\u00f3lidos s\u00e3o normalmente medidos utilizando dilat\u00f3metros (de haste) ou analisadores termomec\u00e2nicos (TMA). Neste caso, a amostra \u00e9 colocada num forno e contactada com uma haste de press\u00e3o. A mudan\u00e7a no comprimento da amostra \u00e9 transferida para um sensor pela haste de press\u00e3o. Dependendo do forno utilizado, pode ser coberta uma <strong>gama de temperaturas de -263 a +2800 \u00b0C<\/strong>. Dependendo da gama de temperaturas, s\u00e3o utilizadas varetas de vidro de quartzo, \u00f3xido de alum\u00ednio ou grafite. Os transformadores <strong>diferenciais (LVDT &#8211; Linear Variable Differential Transformer)<\/strong> e, mais recentemente, os codificadores \u00f3pticos s\u00e3o normalmente utilizados como sensores.     <\/p><p>Se, devido \u00e0s suas propriedades, as amostras forem dif\u00edceis de processar, fr\u00e1geis ou facilmente deform\u00e1veis, de modo a n\u00e3o poderem suportar a for\u00e7a da haste de contacto, s\u00e3o utilizados dilat\u00f3metros \u00f3pticos, tamb\u00e9m conhecidos como microsc\u00f3pios de aquecimento. Aqui, tal como no caso do dilat\u00f3metro de vareta, a amostra \u00e9 colocada numa estufa. A amostra \u00e9 observada com uma c\u00e2mara cujas imagens s\u00e3o medidas. Ao analisar as imagens, \u00e9 poss\u00edvel observar n\u00e3o s\u00f3 a expans\u00e3o (aqui mesmo em 2 dimens\u00f5es), mas tamb\u00e9m as altera\u00e7\u00f5es de forma e a fus\u00e3o, e calcular os \u00e2ngulos de contacto.   <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-80d22bb elementor-widget__width-initial elementor-invisible elementor-widget elementor-widget-image\" data-id=\"80d22bb\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" width=\"691\" height=\"303\" src=\"https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/Contact-angle.jpg\" class=\"attachment-large size-large wp-image-31831\" alt=\"\" srcset=\"https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/Contact-angle.jpg 691w, https:\/\/www.linseis.com\/wp-content\/uploads\/2024\/07\/Contact-angle-300x132.jpg 300w\" sizes=\"(max-width: 691px) 100vw, 691px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-3112811 elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"3112811\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p>As amostras em p\u00f3 s\u00e3o medidas em adaptadores especiais. Deve ter-se o cuidado de assegurar que o ar contido, mas n\u00e3o a amostra, possa sair (analogamente \u00e0 medi\u00e7\u00e3o de l\u00edquidos). O <strong>grau de compacta\u00e7\u00e3o<\/strong> <strong>(densidade aparente, densidade de vibra\u00e7\u00e3o, densidade de batida)<\/strong> da amostra tamb\u00e9m deve ser tido em conta: n\u00e3o deve ser alterado pelas condi\u00e7\u00f5es de medi\u00e7\u00e3o.  <\/p><p>Os materiais com coeficientes de dilata\u00e7\u00e3o particularmente baixos s\u00e3o medidos atrav\u00e9s de <strong>m\u00e9todos<\/strong> <strong>interferom\u00e9tricos<\/strong>. Neste caso, a luz monocrom\u00e1tica \u00e9 reflectida pela amostra e sofre a interfer\u00eancia de um segundo feixe <strong>(princ\u00edpio do interfer\u00f3metro de Michelson)<\/strong>. A altera\u00e7\u00e3o do comprimento resulta do comprimento de onda da luz utilizada e do n\u00famero de interfer\u00eancias. Estes aparelhos de medi\u00e7\u00e3o s\u00e3o tamb\u00e9m designados por dilat\u00f3metros LASER.   <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-fc98544 elementor-invisible elementor-widget elementor-widget-heading\" data-id=\"fc98544\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;_animation&quot;:&quot;fadeInUp&quot;}\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h3 class=\"elementor-heading-title elementor-size-default\">Medi\u00e7\u00e3o com um dilat\u00f3metro a laser<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-95c1b4b elementor-widget__width-initial elementor-widget elementor-widget-video\" data-id=\"95c1b4b\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;youtube_url&quot;:&quot;https:\\\/\\\/youtu.be\\\/3ON3jPSY9yE&quot;,&quot;video_type&quot;:&quot;youtube&quot;,&quot;controls&quot;:&quot;yes&quot;}\" data-widget_type=\"video.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-wrapper elementor-open-inline\">\n\t\t\t<div class=\"elementor-video\"><\/div>\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-a85613a elementor-widget elementor-widget-spacer\" data-id=\"a85613a\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-2ab5eee e-flex e-con-boxed e-con e-parent\" data-id=\"2ab5eee\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>A dilata\u00e7\u00e3o t\u00e9rmica dos materiais pode causar grandes preju\u00edzos econ\u00f3micos. Na ind\u00fastria da constru\u00e7\u00e3o, por exemplo, \u00e9 necess\u00e1rio prever juntas de dilata\u00e7\u00e3o para compensar as altera\u00e7\u00f5es de comprimento devidas \u00e0s varia\u00e7\u00f5es de temperatura. <\/p>\n","protected":false},"author":3,"featured_media":31819,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"categories":[654],"tags":[],"class_list":["post-103306","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-conhecimentos"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.linseis.com\/pt-pt\/wp-json\/wp\/v2\/posts\/103306","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.linseis.com\/pt-pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.linseis.com\/pt-pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.linseis.com\/pt-pt\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.linseis.com\/pt-pt\/wp-json\/wp\/v2\/comments?post=103306"}],"version-history":[{"count":0,"href":"https:\/\/www.linseis.com\/pt-pt\/wp-json\/wp\/v2\/posts\/103306\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.linseis.com\/pt-pt\/wp-json\/wp\/v2\/media\/31819"}],"wp:attachment":[{"href":"https:\/\/www.linseis.com\/pt-pt\/wp-json\/wp\/v2\/media?parent=103306"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.linseis.com\/pt-pt\/wp-json\/wp\/v2\/categories?post=103306"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.linseis.com\/pt-pt\/wp-json\/wp\/v2\/tags?post=103306"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}