{"id":12810,"date":"2025-04-24T07:52:28","date_gmt":"2025-04-24T07:52:28","guid":{"rendered":"https:\/\/hsmagnet.com\/?p=12412"},"modified":"2025-09-17T02:45:39","modified_gmt":"2025-09-17T02:45:39","slug":"pourquoi-les-aimants-permanents-restent-ils-magnetiques","status":"publish","type":"post","link":"https:\/\/hsmagnet.com\/fr\/2025\/04\/24\/why-do-permanent-magnets-stay-magnetic-%ef%bc%9f\/","title":{"rendered":"Pourquoi les aimants permanents restent-ils magn\u00e9tiques ?"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/hsmagnet.com\/magnetic-materials\/\" data-type=\"link\" data-id=\"https:\/\/hsmagnet.com\/magnetic-materials\/\">Permanent magnets <\/a>are essential in countless applications \u2014 from motors, loudspeakers, and MRI machines to fridge magnets and magnetic tools. What makes them remarkable is their ability to retain magnetism for decades or even centuries. But why can they \u201cremember\u201d their magnetism so well, while other metals lose it instantly?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">To understand this, we first need to explore the <strong>different types of magnetic materials<\/strong>, how they are classified, and the physical principles that allow permanent magnets to resist demagnetization.<\/p>\n\n\n<div class=\"root-eb-toc-ssehr wp-block-essential-blocks-table-of-contents\"><div class=\"eb-parent-wrapper eb-parent-eb-toc-ssehr \"><div class=\"eb-toc-container eb-toc-ssehr  eb-toc-is-not-sticky eb-toc-not-collapsible eb-toc-initially-not-collapsed eb-toc-scrollToTop style-1 list-style-none\" data-scroll-top=\"false\" data-scroll-top-icon=\"fas fa-angle-up\" data-collapsible=\"false\" data-sticky-hide-mobile=\"false\" data-sticky=\"false\" data-scroll-target=\"scroll_to_toc\" data-copy-link=\"false\" data-editor-type=\"\" data-hide-desktop=\"false\" data-hide-tab=\"false\" data-hide-mobile=\"false\" data-itemcollapsed=\"false\" data-highlight-scroll=\"false\"><div class=\"eb-toc-header\"><h2 class=\"eb-toc-title\">Table of Contents<\/h2><\/div><div class=\"eb-toc-wrapper \" data-headers=\"[{&quot;level&quot;:2,&quot;content&quot;:&quot;1. Magnetic Material Classification: Hard vs. Soft Magnetic Materials&quot;,&quot;text&quot;:&quot;1. Magnetic Material Classification: Hard vs. Soft Magnetic Materials&quot;,&quot;link&quot;:&quot;1-magnetic-material-classification-hard-vs-soft-magnetic-materials&quot;},{&quot;level&quot;:3,&quot;content&quot;:&quot;Key Difference: Coercivity&quot;,&quot;text&quot;:&quot;Key Difference: Coercivity&quot;,&quot;link&quot;:&quot;key-difference-coercivity&quot;},{&quot;level&quot;:2,&quot;content&quot;:&quot;2. Why Permanent Magnets Stay Magnetic&quot;,&quot;text&quot;:&quot;2. Why Permanent Magnets Stay Magnetic&quot;,&quot;link&quot;:&quot;2-why-permanent-magnets-stay-magnetic&quot;},{&quot;level&quot;:3,&quot;content&quot;:&quot;(1) High Coercivity \\u2013 Resistance to Reverse Fields&quot;,&quot;text&quot;:&quot;(1) High Coercivity \\u2013 Resistance to Reverse Fields&quot;,&quot;link&quot;:&quot;1-high-coercivity-resistance-to-reverse-fields&quot;},{&quot;level&quot;:3,&quot;content&quot;:&quot;(2) Stable Magnetic Domain Alignment&quot;,&quot;text&quot;:&quot;(2) Stable Magnetic Domain Alignment&quot;,&quot;link&quot;:&quot;2-stable-magnetic-domain-alignment&quot;},{&quot;level&quot;:3,&quot;content&quot;:&quot;(3) High Curie Temperature \\u2013 Thermal Stability&quot;,&quot;text&quot;:&quot;(3) High Curie Temperature \\u2013 Thermal Stability&quot;,&quot;link&quot;:&quot;3-high-curie-temperature-thermal-stability&quot;},{&quot;level&quot;:3,&quot;content&quot;:&quot;(4) Optimized Microstructure&quot;,&quot;text&quot;:&quot;(4) Optimized Microstructure&quot;,&quot;link&quot;:&quot;4-optimized-microstructure&quot;},{&quot;level&quot;:3,&quot;content&quot;:&quot;(5) Resistance to Environmental Factors&quot;,&quot;text&quot;:&quot;(5) Resistance to Environmental Factors&quot;,&quot;link&quot;:&quot;5-resistance-to-environmental-factors&quot;},{&quot;level&quot;:2,&quot;content&quot;:&quot;3. How to Separate Permanent Magnets from Soft Magnetic Materials&quot;,&quot;text&quot;:&quot;3. How to Separate Permanent Magnets from Soft Magnetic Materials&quot;,&quot;link&quot;:&quot;3-how-to-separate-permanent-magnets-from-soft-magnetic-materials&quot;},{&quot;level&quot;:2,&quot;content&quot;:&quot;4. The Science Behind Coercivity&quot;,&quot;text&quot;:&quot;4. The Science Behind Coercivity&quot;,&quot;link&quot;:&quot;4-the-science-behind-coercivity&quot;},{&quot;level&quot;:2,&quot;content&quot;:&quot;5. Summary&quot;,&quot;text&quot;:&quot;5. Summary&quot;,&quot;link&quot;:&quot;5-summary&quot;}]\" data-visible=\"[true,true,true,true,true,true]\" data-delete-headers=\"[{&quot;label&quot;:&quot;1. Magnetic Material Classification: Hard vs. Soft Magnetic Materials&quot;,&quot;value&quot;:&quot;1-magnetic-material-classification-hard-vs-soft-magnetic-materials&quot;,&quot;isDelete&quot;:false},{&quot;label&quot;:&quot;Key Difference: Coercivity&quot;,&quot;value&quot;:&quot;key-difference-coercivity&quot;,&quot;isDelete&quot;:false},{&quot;label&quot;:&quot;2. Why Permanent Magnets Stay Magnetic&quot;,&quot;value&quot;:&quot;2-why-permanent-magnets-stay-magnetic&quot;,&quot;isDelete&quot;:false},{&quot;label&quot;:&quot;(1) High Coercivity \\u2013 Resistance to Reverse Fields&quot;,&quot;value&quot;:&quot;1-high-coercivity-resistance-to-reverse-fields&quot;,&quot;isDelete&quot;:false},{&quot;label&quot;:&quot;(2) Stable Magnetic Domain Alignment&quot;,&quot;value&quot;:&quot;2-stable-magnetic-domain-alignment&quot;,&quot;isDelete&quot;:false},{&quot;label&quot;:&quot;(3) High Curie Temperature \\u2013 Thermal Stability&quot;,&quot;value&quot;:&quot;3-high-curie-temperature-thermal-stability&quot;,&quot;isDelete&quot;:false},{&quot;label&quot;:&quot;(4) Optimized Microstructure&quot;,&quot;value&quot;:&quot;4-optimized-microstructure&quot;,&quot;isDelete&quot;:false},{&quot;label&quot;:&quot;(5) Resistance to Environmental Factors&quot;,&quot;value&quot;:&quot;5-resistance-to-environmental-factors&quot;,&quot;isDelete&quot;:false},{&quot;label&quot;:&quot;3. How to Separate Permanent Magnets from Soft Magnetic Materials&quot;,&quot;value&quot;:&quot;3-how-to-separate-permanent-magnets-from-soft-magnetic-materials&quot;,&quot;isDelete&quot;:false},{&quot;label&quot;:&quot;4. The Science Behind Coercivity&quot;,&quot;value&quot;:&quot;4-the-science-behind-coercivity&quot;,&quot;isDelete&quot;:false},{&quot;label&quot;:&quot;5. Summary&quot;,&quot;value&quot;:&quot;5-summary&quot;,&quot;isDelete&quot;:false}]\" data-smooth=\"true\" data-top-offset=\"\"><div class=\"eb-toc__list-wrap\"><ul class=\"eb-toc__list\"><li><a href=\"#1-magnetic-material-classification-hard-vs-soft-magnetic-materials\">1. Magnetic Material Classification: Hard vs. Soft Magnetic Materials<\/a><ul class=\"eb-toc__list\"><li><a href=\"#key-difference-coercivity\">Key Difference: Coercivity<\/a><\/li><\/ul><li><a href=\"#2-why-permanent-magnets-stay-magnetic\">2. Why Permanent Magnets Stay Magnetic<\/a><ul class=\"eb-toc__list\"><li><a href=\"#1-high-coercivity-resistance-to-reverse-fields\">(1) High Coercivity \u2013 Resistance to Reverse Fields<\/a><li><a href=\"#2-stable-magnetic-domain-alignment\">(2) Stable Magnetic Domain Alignment<\/a><li><a href=\"#3-high-curie-temperature-thermal-stability\">(3) High Curie Temperature \u2013 Thermal Stability<\/a><li><a href=\"#4-optimized-microstructure\">(4) Optimized Microstructure<\/a><li><a href=\"#5-resistance-to-environmental-factors\">(5) Resistance to Environmental Factors<\/a><\/li><\/ul><li><a href=\"#3-how-to-separate-permanent-magnets-from-soft-magnetic-materials\">3. How to Separate Permanent Magnets from Soft Magnetic Materials<\/a><li><a href=\"#4-the-science-behind-coercivity\">4. The Science Behind Coercivity<\/a><li><a href=\"#5-summary\">5. Summary<\/a><\/ul><\/div><\/div><\/div><\/div><\/div>\n\n\n<h2 class=\"wp-block-heading\">1. Magnetic Material Classification: Hard vs. Soft Magnetic Materials<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Magnetic materials can be broadly divided into <strong>permanent (hard)<\/strong> and <strong>soft<\/strong> magnetic materials based on their ability to retain magnetism.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th><strong>Type<\/strong><\/th><th><strong>Coercivity<\/strong><\/th><th><strong>Key Feature<\/strong><\/th><th><strong>Example Materials<\/strong><\/th><th><strong>Applications<\/strong><\/th><\/tr><\/thead><tbody><tr><td><strong>Permanent (Hard) Magnetic Materials<\/strong><\/td><td>High (hundreds to thousands of kA\/m)<\/td><td>Retain magnetism for long periods<\/td><td>Neodymium (NdFeB), Samarium Cobalt (SmCo), Ferrite, Alnico<\/td><td>Motors, generators, sensors, magnetic locks<\/td><\/tr><tr><td><strong>Soft Magnetic Materials<\/strong><\/td><td>Low (few A\/m to tens of A\/m)<\/td><td>Easily magnetized and demagnetized<\/td><td>Pure iron, silicon steel, permalloy<\/td><td>Transformers, inductors, electromagnets<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Key Difference: Coercivity<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Coercivity<\/strong> is the measure of a material\u2019s resistance to losing its magnetism when an opposing magnetic field is applied.<\/li>\n\n\n\n<li>Permanent magnets have <strong>high coercivity<\/strong>, meaning it takes a <em>very strong reverse field<\/em> to demagnetize them.<\/li>\n\n\n\n<li>Soft magnets have <strong>low coercivity<\/strong>, which makes them ideal for applications requiring rapid magnetization and demagnetization cycles.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Bar-chart-comparing-coercivity-of-hard-and-soft-magnetic-materials-like-NdFeB-and-pure-iron-1024x683.webp\" alt=\"Bar chart comparing coercivity of hard and soft magnetic materials like NdFeB and pure iron\" class=\"wp-image-13813\" srcset=\"https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Bar-chart-comparing-coercivity-of-hard-and-soft-magnetic-materials-like-NdFeB-and-pure-iron-1024x683.webp 1024w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Bar-chart-comparing-coercivity-of-hard-and-soft-magnetic-materials-like-NdFeB-and-pure-iron-300x200.webp 300w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Bar-chart-comparing-coercivity-of-hard-and-soft-magnetic-materials-like-NdFeB-and-pure-iron-768x512.webp 768w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Bar-chart-comparing-coercivity-of-hard-and-soft-magnetic-materials-like-NdFeB-and-pure-iron-600x400.webp 600w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Bar-chart-comparing-coercivity-of-hard-and-soft-magnetic-materials-like-NdFeB-and-pure-iron.webp 1536w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">2. Why Permanent Magnets Stay Magnetic<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">(1) <strong>High Coercivity \u2013 Resistance to Reverse Fields<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Permanent magnets are made from materials whose atomic structure and chemical composition give them very high coercivity.<br>Example:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong><a href=\"https:\/\/hsmagnet.com\/magnetic-materials\/ndfeb-magnets\/\" data-type=\"link\" data-id=\"https:\/\/hsmagnet.com\/magnetic-materials\/ndfeb-magnets\/\">Neodymium magnets<\/a><\/strong> can have coercivity values exceeding <strong>1000 kA\/m<\/strong>.<\/li>\n\n\n\n<li>In everyday life, typical stray magnetic fields are far too weak to affect them.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">(2) <strong>Stable Magnetic Domain Alignment<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Inside a magnetic material, tiny regions called <strong>magnetic domains<\/strong> each act like a small magnet.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>In permanent magnets, these domains are \u201clocked\u201d in one direction during manufacturing.<\/li>\n\n\n\n<li>This alignment is held in place by <strong>magnetic anisotropy<\/strong> \u2014 a property that makes certain crystal orientations energetically more favorable.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">In contrast, in soft magnets, domains can shift or flip easily under even weak opposing fields.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"1024\" src=\"https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Diagram-of-magnetic-domains-in-permanent-magnets-showing-stable-alignment-and-domain-wall-pinning-1024x1024.webp\" alt=\"Diagram of magnetic domains in permanent magnets, showing stable alignment and domain wall pinning\" class=\"wp-image-13815\" srcset=\"https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Diagram-of-magnetic-domains-in-permanent-magnets-showing-stable-alignment-and-domain-wall-pinning-1024x1024.webp 1024w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Diagram-of-magnetic-domains-in-permanent-magnets-showing-stable-alignment-and-domain-wall-pinning-300x300.webp 300w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Diagram-of-magnetic-domains-in-permanent-magnets-showing-stable-alignment-and-domain-wall-pinning-150x150.webp 150w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Diagram-of-magnetic-domains-in-permanent-magnets-showing-stable-alignment-and-domain-wall-pinning-768x768.webp 768w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Diagram-of-magnetic-domains-in-permanent-magnets-showing-stable-alignment-and-domain-wall-pinning-1536x1536.webp 1536w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Diagram-of-magnetic-domains-in-permanent-magnets-showing-stable-alignment-and-domain-wall-pinning-600x600.webp 600w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Diagram-of-magnetic-domains-in-permanent-magnets-showing-stable-alignment-and-domain-wall-pinning-100x100.webp 100w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Diagram-of-magnetic-domains-in-permanent-magnets-showing-stable-alignment-and-domain-wall-pinning.webp 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">(3) <strong>High Curie Temperature \u2013 Thermal Stability<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The <strong>Curie temperature<\/strong> is the point at which a magnet loses its magnetic order due to heat.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Alnico: <strong>750\u2013860 \u00b0C<\/strong> (1382\u20131580 \u00b0F)<\/li>\n\n\n\n<li>Ferrite: <strong>~450 \u00b0C<\/strong> (842 \u00b0F)<\/li>\n\n\n\n<li>NdFeB: <strong>~310 \u00b0C<\/strong> (590 \u00b0F)<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Below this temperature, the atomic magnetic moments remain aligned. The higher the Curie temperature, the better the magnet resists thermal demagnetization.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">(4) <strong>Optimized Microstructure<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Modern permanent magnets are engineered to trap magnetic domains in place:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Fine-grained crystals<\/strong> reduce the movement of domain walls.<\/li>\n\n\n\n<li><strong>Grain boundary phases<\/strong> act as barriers against demagnetization.<\/li>\n\n\n\n<li>Example: <strong>Nd\u2082Fe\u2081\u2084B crystals<\/strong> in neodymium magnets are surrounded by Nd-rich grain boundaries that block reversal of domain alignment.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">(5) <strong>Resistance to Environmental Factors<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">While permanent magnets are stable, they can lose magnetism due to:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Corrosion<\/strong> (especially NdFeB, which requires nickel or epoxy coating)<\/li>\n\n\n\n<li><strong>Severe mechanical shock<\/strong><\/li>\n\n\n\n<li><strong>Exposure to very strong reverse magnetic fields<\/strong><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">With proper coating, handling, and storage, high-quality permanent magnets can maintain over 95% of their original magnetism even after decades.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">3. How to Separate Permanent Magnets from Soft Magnetic Materials<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">In industrial and laboratory settings, distinguishing between <strong>permanent magnets<\/strong> and <strong>soft magnetic materials<\/strong> is important:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>Method<\/th><th>Observation<\/th><\/tr><\/thead><tbody><tr><td><strong>Check Retentivity<\/strong><\/td><td>After removing from a magnetizing field, a permanent magnet keeps strong magnetism; soft magnet loses it quickly.<\/td><\/tr><tr><td><strong>Coercivity Testing<\/strong><\/td><td>Apply a reverse field and measure the demagnetizing force needed.<\/td><\/tr><tr><td><strong>Magnet Pull Test<\/strong><\/td><td>Compare the holding force before and after exposure to opposing fields.<\/td><\/tr><tr><td><strong>Material Identification<\/strong><\/td><td>Use chemical composition analysis (NdFeB, SmCo, Alnico = hard; pure Fe, permalloy = soft).<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Flowchart-for-distinguishing-permanent-from-soft-magnets-using-coercivity-testing-and-pull-tests-1024x683.webp\" alt=\"Flowchart for distinguishing permanent from soft magnets using coercivity testing and pull tests\" class=\"wp-image-13814\" srcset=\"https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Flowchart-for-distinguishing-permanent-from-soft-magnets-using-coercivity-testing-and-pull-tests-1024x683.webp 1024w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Flowchart-for-distinguishing-permanent-from-soft-magnets-using-coercivity-testing-and-pull-tests-300x200.webp 300w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Flowchart-for-distinguishing-permanent-from-soft-magnets-using-coercivity-testing-and-pull-tests-768x512.webp 768w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Flowchart-for-distinguishing-permanent-from-soft-magnets-using-coercivity-testing-and-pull-tests-600x400.webp 600w, https:\/\/hsmagnet.com\/wp-content\/uploads\/2025\/04\/Flowchart-for-distinguishing-permanent-from-soft-magnets-using-coercivity-testing-and-pull-tests.webp 1536w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">4. The Science Behind Coercivity<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Coercivity depends on:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Magnetocrystalline anisotropy<\/strong> \u2013 Atomic lattice prefers specific spin directions.<\/li>\n\n\n\n<li><strong>Microstructural defects<\/strong> \u2013 Can either pin domain walls (in hard magnets) or allow free movement (in soft magnets).<\/li>\n\n\n\n<li><strong>Chemical composition<\/strong> \u2013 Elements like cobalt, rare earths, and aluminum increase coercivity.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">High coercivity means a magnet \u201cremembers\u201d its original magnetization, making it resistant to accidental demagnetization from environmental fields or minor shocks.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">5. Summary<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Permanent magnets remain magnetic because:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>They have <strong>high coercivity<\/strong>, resisting reverse fields.<\/li>\n\n\n\n<li>Their <strong>magnetic domains<\/strong> are strongly locked in place.<\/li>\n\n\n\n<li>They have a <strong>high Curie temperature<\/strong>, resisting thermal effects.<\/li>\n\n\n\n<li>Their <strong>microstructure<\/strong> is optimized for stability.<\/li>\n\n\n\n<li>They are <strong>protected<\/strong> from corrosion and mechanical damage.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">By contrast, soft magnetic materials are designed to switch magnetism on and off easily, making them ideal for electromagnets and transformer cores \u2014 but not for long-term magnetic retention.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p class=\"wp-block-paragraph\">If you need expert advice on choosing the right magnet \u2014 whether high-coercivity permanent magnets for motors, or soft magnetic cores for transformers \u2014 feel free to <a href=\"https:\/\/hsmagnet.com\/contact-us\/\" data-type=\"link\" data-id=\"https:\/\/hsmagnet.com\/contact-us\/\">contact us<\/a>. Our engineering team can provide both technical guidance and customized magnet solutions.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Permanent magnets are essential in countless applications \u2014 from motors, loudspeakers, and MRI machines to fridge magnets and magnetic tools. What makes them remarkable is their ability to retain magnetism for decades or even centuries. But why can they \u201cremember\u201d their magnetism so well, while other metals lose it instantly? To understand this, we first [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":13681,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_eb_attr":"","footnotes":""},"categories":[23],"tags":[],"class_list":["post-12810","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-magnet-tech"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.7 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>permanent magnets stay magnetic<\/title>\n<meta name=\"description\" content=\"Discover how permanent magnets retain their magnetism for years! 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