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100% Gas-Tight Structure
![\"\"](\"https:\/\/www.sapphiretube.com\/wp-content\/uploads\/2026\/01\/Sapphire-Thermocouple-Tube-Single-Crystal-Al\u2082O\u2083-Thermocouple-Protection-Sheath-for-Extreme-Environments-3-300x300.png\")
Single crystal sapphire contains no pores, effectively isolating the thermocouple from ambient gas diffusion and aggressive atmospheres.<\/p>\n<\/li>\n - \n
Ultra-High Temperature Resistance
With a melting point of 2030 \u00b0C, sapphire thermocouple tubes maintain dimensional stability and mechanical integrity at temperatures up to 2000 \u00b0C.<\/p>\n<\/li>\n - \n
Exceptional Mechanical Strength
Mohs hardness of 9, providing outstanding resistance to wear, pressure, and mechanical shock in harsh operating conditions.<\/p>\n<\/li>\n - \n
Superior Chemical Stability
Highly resistant to acids, alkalis, metal vapors, and reactive gases, preventing chemical attack on thermocouples.<\/p>\n<\/li>\n - \n
Excellent Electrical Insulation
High dielectric strength ensures reliable performance in high-temperature and electrically demanding environments.<\/p>\n<\/li>\n - \n
Ultra-High Purity Material
Purity up to 99.995%, ensuring long-term stability and consistent performance at elevated temperatures.<\/p>\n<\/li>\n<\/ul>\nTypical Specifications<\/h3>\n
\n\n\n\n
\n \nParameter<\/th>\n Value<\/th>\n<\/tr>\n<\/thead>\n \n Material<\/td>\n Single Crystal Sapphire (Al\u2082O\u2083)<\/td>\n<\/tr>\n \n Inner Diameter<\/td>\n 15 mm<\/td>\n<\/tr>\n \n Outer Diameter<\/td>\n 18 mm<\/td>\n<\/tr>\n \n Length<\/td>\n 280 mm<\/td>\n<\/tr>\n \n Dimensional Tolerance<\/td>\n \u00b10.05 mm<\/td>\n<\/tr>\n \n Concentricity<\/td>\n \u00b10.05 mm<\/td>\n<\/tr>\n \n Surface Finish<\/td>\n As-grown<\/td>\n<\/tr>\n \n Max Operating Temperature<\/td>\n \u2264 2000 \u00b0C<\/td>\n<\/tr>\n \n Gas Tightness<\/td>\n 100%<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n \n
Customization available: inner diameter, outer diameter, length, end shape, and surface condition can be customized according to application requirements.<\/p>\n<\/blockquote>\n
Manufacturing Technology<\/h3>\n
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KY \/ EFG single crystal growth<\/p>\n<\/li>\n
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One-piece forming, no sintering interfaces<\/p>\n<\/li>\n
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Dense, pore-free crystal structure<\/p>\n<\/li>\n
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Far superior to conventional corundum ceramic thermocouple sheaths<\/p>\n<\/li>\n<\/ul>\n
![\"\"](\"https:\/\/www.sapphiretube.com\/wp-content\/uploads\/2026\/01\/Sapphire-Thermocouple-Tube-Single-Crystal-Al\u2082O\u2083-Thermocouple-Protection-Sheath-for-Extreme-Environments-2-300x300.png\")
Applications<\/h3>\n- \n
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High-temperature vacuum furnaces<\/p>\n<\/li>\n
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Single crystal growth furnaces (sapphire, SiC, oxide crystals)<\/p>\n<\/li>\n
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Semiconductor and advanced materials laboratories<\/p>\n<\/li>\n
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Chemical reactors and petrochemical processing<\/p>\n<\/li>\n
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Glass manufacturing and blast furnaces<\/p>\n<\/li>\n
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Metallurgical and hydrogen production processes<\/p>\n<\/li>\n<\/ul>\n
Sapphire thermocouple tubes are ideal for applications where traditional ceramic or corundum tubes cannot meet stability, purity, or lifetime requirements.<\/p>\n
FAQs<\/h2>\n
Q1: Why choose a sapphire thermocouple tube instead of a ceramic or corundum tube?<\/h3>\n
Sapphire thermocouple tubes offer 100% gas tightness, higher temperature capability, superior chemical resistance, and no reaction with molten metals, whereas ceramic tubes may contain pores, react with metals, or deform at high temperatures.<\/p>\n
Q2: What is the maximum operating temperature of a sapphire thermocouple tube?<\/h3>\n
Sapphire thermocouple tubes can reliably operate at temperatures up to 2000 \u00b0C, with a melting point of approximately 2030 \u00b0C, covering most high-temperature thermocouple applications.<\/p>\n
Q3: Can sapphire thermocouple tubes be customized?<\/h3>\n
Yes. Sapphire thermocouple tubes can be customized in length, inner and outer diameter, end geometry, and surface finish to meet specific furnace designs and measurement conditions.<\/p>","protected":false},"excerpt":{"rendered":"
The Sapphire Thermocouple Tube is manufactured from high-purity single crystal sapphire (Al\u2082O\u2083) using KY or EFG growth technology and formed in one piece.<\/p>","protected":false},"featured_media":2644,"comment_status":"open","ping_status":"closed","template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","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":"","ast-disable-related-posts":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"default","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"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-opacity":"","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-opacity":"","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-opacity":"","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-opacity":"","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-opacity":"","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-opacity":"","overlay-gradient":""}}},"product_brand":[],"product_cat":[18],"product_tag":[56,57,53,54,52,55],"class_list":{"0":"post-2643","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-sapphire-tube","7":"product_tag-al2o3-sapphire-tube","8":"product_tag-high-temperature-thermocouple-protection","9":"product_tag-sapphire-thermocouple-protection-tube","10":"product_tag-sapphire-thermocouple-sheath","11":"product_tag-sapphire-thermocouple-tube","12":"product_tag-single-crystal-sapphire-tube","13":"desktop-align-left","14":"tablet-align-left","15":"mobile-align-left","16":"ast-product-gallery-layout-horizontal-slider","17":"ast-product-tabs-layout-horizontal","19":"first","20":"instock","21":"shipping-taxable","22":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/www.sapphiretube.com\/ja\/wp-json\/wp\/v2\/product\/2643","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.sapphiretube.com\/ja\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/www.sapphiretube.com\/ja\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/www.sapphiretube.com\/ja\/wp-json\/wp\/v2\/comments?post=2643"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.sapphiretube.com\/ja\/wp-json\/wp\/v2\/media\/2644"}],"wp:attachment":[{"href":"https:\/\/www.sapphiretube.com\/ja\/wp-json\/wp\/v2\/media?parent=2643"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/www.sapphiretube.com\/ja\/wp-json\/wp\/v2\/product_brand?post=2643"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/www.sapphiretube.com\/ja\/wp-json\/wp\/v2\/product_cat?post=2643"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/www.sapphiretube.com\/ja\/wp-json\/wp\/v2\/product_tag?post=2643"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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