{"id":23357,"date":"2024-07-18T07:40:53","date_gmt":"2024-07-18T05:40:53","guid":{"rendered":"https:\/\/www.linseis.com\/what-does-thermal-conductivity-mean\/"},"modified":"2025-08-27T14:10:37","modified_gmt":"2025-08-27T12:10:37","slug":"what-does-thermal-conductivity-mean","status":"publish","type":"post","link":"https:\/\/www.linseis.com\/en\/wiki\/what-does-thermal-conductivity-mean\/","title":{"rendered":"What does thermal conductivity mean?"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"23357\" class=\"elementor elementor-23357 elementor-10305\" 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-5f69a51 elementor-toc--minimized-on-tablet elementor-invisible elementor-widget elementor-widget-table-of-contents\" data-id=\"5f69a51\" 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\tTable of Contents\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__5f69a51\" 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__5f69a51\" 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__5f69a51\" 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-ffaef65 elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"ffaef65\" 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>In general, the thermal conductivity of the expression is the amount of heat that flows through a 1x1x1m cube of a material within 1 second if there is a temperature gradient of exactly 1 K between two opposite sides.<br>This makes thermal conductivity a characteristic material property with its own symbol (\u03bb &#8211; &#8220;lambda&#8221;) and its own SI unit W \/ mK. Its reciprocal value is the specific thermal resistance. <\/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-e4fd176 elementor-invisible elementor-widget elementor-widget-heading\" data-id=\"e4fd176\" 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\">Scientific definition<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-00709c7 elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"00709c7\" 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>The scientific definition of thermal conductivity claims it as the material property that describes the heat transport within a sample. For each sample temperature, it is obtained from the product of density, thermal diffusivity and specific heat capacity at that temperature (equation 1) and can be described as the negative quotient of heat flux density and temperature gradient (equation 2). The example in (equation 3) serves to illustrate this.     <\/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-e3579fe elementor-widget__width-initial elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"e3579fe\" 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>\u03bb = \u03c1 * cp * \u03b1 (1)<br><br>\u03bb = thermal conductivity, \u03c1 = density, cp = specific heat capacity, \u03b1 = thermal diffusivity <br><br>\u03bb = -q \/ \u2206T (2)<br><br>\u03bb = thermal conductivity, q = average heat flux density, \u2206T = temperature gradient<\/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-a0441a3 elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"a0441a3\" 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>If this definition is used to consider, for example, a cylindrical sample, the following calculations can be performed: If an ideal homogeneous cylinder of length l and constant cross-section A is considered, which is insulated on its side and can only have one temperature change at its two ends, the temperature gradient over its length is (\u2206T) \/ l. The density of the heat flow with the direction from the hot to the cold side is <strong>\u03bb<\/strong> * (\u2206T) \/ l.<\/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-ec40c41 elementor-widget__width-initial elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"ec40c41\" 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>If we consider the cross-section A, there is a <a href=\"https:\/\/www.linseis.com\/en\/properties\/heat-flow-rate\/\"><strong>heat flow Q<\/strong><\/a>which can be calculated using (equation 3):<\/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-833aa4c elementor-widget__width-initial elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"833aa4c\" 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>Q = (A * \u03bb * \u2206T) \/ l (3)<br><br>\u03bb = thermal conductivity, Q = heat flow, \u2206T = temperature gradient, A = cross-section, l = length<\/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-26f20eb elementor-invisible elementor-widget elementor-widget-heading\" data-id=\"26f20eb\" 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\">Thermal conductivity measurement (methods):<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-16299ff e-con-full e-flex e-con e-child\" data-id=\"16299ff\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div class=\"elementor-element elementor-element-604b7b0 e-con-full e-flex e-con e-child\" data-id=\"604b7b0\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-1dca64d elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"1dca64d\" 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>The measurement methods for determining thermal conductivity are varied, but can be divided into two basic groups for a better overview: <strong>transient and stationary measurement methods<\/strong>.<\/p><p>In our video, our two scientists explain the difference between these methods.<\/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-5ec91c4 e-con-full e-flex e-con e-child\" data-id=\"5ec91c4\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-34d22ea elementor-widget elementor-widget-video\" data-id=\"34d22ea\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;youtube_url&quot;:&quot;https:\\\/\\\/youtu.be\\\/jylkWNrZvLs&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>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-c55e164 elementor-widget__width-initial elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"c55e164\" 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\tIf a material is heated locally, the temperature distribution within the body changes until it is evenly distributed and stable after a certain time. The phase shortly after the start of the heat input, in which the temperature distribution is still changing, is called the transient phase. A stable temperature distribution is referred to as a steady state.\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-9a25086 elementor-invisible elementor-widget elementor-widget-heading\" data-id=\"9a25086\" 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\">Stationary measuring methods<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-a1f545e elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"a1f545e\" 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>plate process, such as the &#8220;<a href=\"https:\/\/www.linseis.com\/en\/methods\/guarded-hot-plate-ghp\/\" data-auto-event-observed=\"true\"><strong>Guarded Hot Plate<\/strong><\/a>&#8220;, the &#8220;<a href=\"https:\/\/www.linseis.com\/en\/instruments\/thermal-conductivity\/hfm-l57\/\" data-auto-event-observed=\"true\"><strong>Heat Flow Mete<\/strong><\/a><b><u>r<\/u><\/b>&#8220;, or the &#8220;<a href=\"https:\/\/www.linseis.com\/en\/instruments\/thermal-conductivity\/tim-tester-l58\/\" data-auto-event-observed=\"true\"><strong>Thermal Interface Material Tester<\/strong><\/a>&#8221; belong to the stationary measuring methods.<\/p><p>The material sample is placed between a heated and a cooled plate. This results in a temperature gradient and consequently also a heat flow along the sample, which is monitored until it approaches a constant final value. <\/p><p>If the sample thickness and the measured heat flow are known, the thermal conductivity of the sample can be calculated. With the TIM tester, the thermal resistance can be measured under variable load or compression and the thermal conductivity and thermal contact resistance can be determined from this. <\/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-3fa3614 elementor-invisible elementor-widget elementor-widget-heading\" data-id=\"3fa3614\" 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\">Transient measurement methods<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-5f8e951 elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"5f8e951\" 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 data-start=\"212\" data-end=\"863\">A well-known example of transient processes is the <strong data-start=\"268\" data-end=\"293\">laser flash process<\/strong> &#8211; a classic that has been around since 1975 and is still in use worldwide today. The reason: despite its high costs and technical complexity, it delivers extremely precise results, even under extreme conditions of up to <strong data-start=\"522\" data-end=\"534\">2,800 \u00b0C<\/strong>. The sample disk is heated on one side by a short, high-energy laser or light flash. An infrared detector then measures the temperature rise on the opposite side. In combination with the sample thickness, the <strong data-start=\"816\" data-end=\"843\">thermal diffusivity<\/strong> can be calculated using a thermal conductivity model.    <\/p><p data-start=\"865\" data-end=\"1410\"><strong data-start=\"870\" data-end=\"909\">Heating wire and heating strip methods<\/strong> (e.g. the transient hot bridge method) also belong to the transient techniques. They are flexible, can be used in a wide variety of sensor configurations and therefore cover a large measuring range. A heating wire embedded in a substrate constantly emits heat. The resulting, time-dependent temperature distribution in the sample and sensor is recorded with an integrated thermometer &#8211; a direct indicator of the <strong data-start=\"1355\" data-end=\"1393\">thermal transport properties<\/strong> of the material.   <\/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-ad234c7 elementor-invisible elementor-widget elementor-widget-heading\" data-id=\"ad234c7\" 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\">Special feature: Measurement of thermal conductivity on thin layers<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-3a78645 elementor-invisible elementor-widget elementor-widget-text-editor\" data-id=\"3a78645\" 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 data-start=\"151\" data-end=\"768\">A special case is the measurement of thermal conductivity in <strong data-start=\"214\" data-end=\"265\">thin layers in the nanometer to micrometer range<\/strong>. Although these measurements are partly based on the same basic principles as for solid samples, the <strong data-start=\"370\" data-end=\"422\">practical implementation differs significantly<\/strong>. Instead of the classic laser flash method, for example, <strong data-start=\"499\" data-end=\"539\">time-domain thermoreflectance (TDTR)<\/strong> is used here, while the <strong data-start=\"565\" data-end=\"584\">3-omega method<\/strong> is a specialized form of the heating strip method. These adaptations are necessary in order to reliably capture the special boundary conditions of ultra-thin layers.   <\/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-e15a843 elementor-widget elementor-widget-spacer\" data-id=\"e15a843\" 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-ac0ae57 e-flex e-con-boxed e-con e-parent\" data-id=\"ac0ae57\" 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-1ef89fa elementor-widget elementor-widget-html\" data-id=\"1ef89fa\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"html.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<script type=\"application\/ld+json\">{\r\n  \"@context\":\"https:\/\/schema.org\",\r\n  \"@type\":\"FAQPage\",\r\n  \"mainEntity\":[\r\n    {\r\n      \"@type\":\"Question\",\r\n      \"name\":\"Was ist W\u00e4rmeleitf\u00e4higkeit und welches Symbol\/Einheit hat sie?\",\r\n      \"acceptedAnswer\":{\r\n        \"@type\":\"Answer\",\r\n        \"text\":\"Die W\u00e4rmeleitf\u00e4higkeit \u03bb beschreibt die W\u00e4rmemenge, die pro Sekunde durch einen 1\u00d71\u00d71-m-W\u00fcrfel eines Materials flie\u00dft, wenn zwischen zwei gegen\u00fcberliegenden Seiten ein Temperaturgef\u00e4lle von 1 K anliegt. Einheit: W\/(m\u00b7K).\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\":\"Question\",\r\n      \"name\":\"Wie lautet die wissenschaftliche Definition von \u03bb?\",\r\n      \"acceptedAnswer\":{\r\n        \"@type\":\"Answer\",\r\n        \"text\":\"\u03bb ist die Materialeigenschaft f\u00fcr den W\u00e4rmetransport. F\u00fcr jede Probentemperatur gilt \u03bb = \u03c1 \u00b7 cp \u00b7 \u03b1. Alternativ als Fourier-Gesetz: \u03bb = \u2212 q \/ \u2207T (bzw. in 1D \u2212q\/\u0394T).\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\":\"Question\",\r\n      \"name\":\"Wie verkn\u00fcpft man W\u00e4rmestrom, Geometrie und Temperaturgef\u00e4lle?\",\r\n      \"acceptedAnswer\":{\r\n        \"@type\":\"Answer\",\r\n        \"text\":\"F\u00fcr einen zylindrischen Probek\u00f6rper mit L\u00e4nge l und Querschnitt A gilt: Q = (A \u00b7 \u03bb \u00b7 \u0394T) \/ l. Dabei ist Q der W\u00e4rmestrom.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\":\"Question\",\r\n      \"name\":\"Welche Hauptklassen von Messverfahren gibt es?\",\r\n      \"acceptedAnswer\":{\r\n        \"@type\":\"Answer\",\r\n        \"text\":\"Station\u00e4re und transiente Verfahren. Station\u00e4r: Messung bei erreichtem Gleichgewichtszustand. Transient: Auswertung der zeitlichen Temperaturantwort direkt nach dem W\u00e4rmeeintrag.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\":\"Question\",\r\n      \"name\":\"Welche station\u00e4ren Methoden sind \u00fcblich?\",\r\n      \"acceptedAnswer\":{\r\n        \"@type\":\"Answer\",\r\n        \"text\":\"Guarded Hot Plate (GHP), Heat Flow Meter (HFM) und der Thermal Interface Material Tester (TIM). Beim TIM-Tester lassen sich zus\u00e4tzlich der thermische Widerstand unter Last\/Kompression und der Kontaktwiderstand bestimmen.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\":\"Question\",\r\n      \"name\":\"Welche transienten Methoden werden verwendet?\",\r\n      \"acceptedAnswer\":{\r\n        \"@type\":\"Answer\",\r\n        \"text\":\"Laser-Flash (LFA) zur Bestimmung der Temperaturleitf\u00e4higkeit aus der transienten Antwort bis ~2800 \u00b0C sowie Heizdraht\/Heizstreifen-Verfahren, z. B. Transient Hot Bridge (THB).\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\":\"Question\",\r\n      \"name\":\"Wie funktioniert die Laser-Flash-Analyse grob?\",\r\n      \"acceptedAnswer\":{\r\n        \"@type\":\"Answer\",\r\n        \"text\":\"Eine Proben\u00adscheibe wird auf einer Seite kurz gepulst erhitzt (Laser\/Blitz). Ein IR-Detektor misst den Temperaturanstieg auf der R\u00fcckseite; daraus wird \u03b1 und in Kombination mit \u03c1 und cp die W\u00e4rmeleitf\u00e4higkeit ermittelt.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\":\"Question\",\r\n      \"name\":\"Was misst das Heizdraht\/Heizstreifen-Prinzip (THB)?\",\r\n      \"acceptedAnswer\":{\r\n        \"@type\":\"Answer\",\r\n        \"text\":\"Ein im Tr\u00e4ger eingebetteter Heizleiter gibt konstant W\u00e4rme ab. Der zeitliche Temperaturanstieg am Sensor dient zur Bestimmung der Transporteigenschaften; durch geeignete Auswertung erh\u00e4lt man \u03b1, \u03bb und \u2013 mit \u03c1 \u2013 cp.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\":\"Question\",\r\n      \"name\":\"Wie misst man W\u00e4rmeleitf\u00e4higkeit in D\u00fcnnschichten?\",\r\n      \"acceptedAnswer\":{\r\n        \"@type\":\"Answer\",\r\n        \"text\":\"F\u00fcr nm\u2013\u03bcm-Schichten werden angepasste Ausf\u00fchrungen genutzt, etwa Time-Domain Thermoreflectance (TDTR) statt LFA sowie die 3-Omega-Methode als Spezialfall des Heizstreifenprinzips.\"\r\n      }\r\n    },\r\n    {\r\n      \"@type\":\"Question\",\r\n      \"name\":\"Ist W\u00e4rmeleitf\u00e4higkeit temperaturabh\u00e4ngig?\",\r\n      \"acceptedAnswer\":{\r\n        \"@type\":\"Answer\",\r\n        \"text\":\"Ja. \u03bb wird f\u00fcr jede Probentemperatur bestimmt; daher sind Angaben zur Temperatur bzw. zum Messbereich wesentlich f\u00fcr die Interpretation.\"\r\n      }\r\n    }\r\n  ]\r\n}\r\n<\/script>\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\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>In general, the thermal conductivity of the expression is the amount of heat that flows through a 1x1x1m cube of a material within 1 second if there is a temperature gradient of exactly 1 K between two opposite sides.<\/p>\n","protected":false},"author":3,"featured_media":10233,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"categories":[106],"tags":[],"class_list":["post-23357","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-wiki"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/posts\/23357","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/comments?post=23357"}],"version-history":[{"count":0,"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/posts\/23357\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/media\/10233"}],"wp:attachment":[{"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/media?parent=23357"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/categories?post=23357"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.linseis.com\/en\/wp-json\/wp\/v2\/tags?post=23357"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}