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Kovar 4J29 Precision Alloy Sheet for Glass Metal Sealing Supplier
As a reliable China manufacturer of Kovar 4J29 precision alloy plates, we offer custom thicknesses, competitive wholesale pricing, ASTM F1684 certified quality, and fast global delivery. Contact our China factory today for bulk Kovar 4J29 low thermal expansion alloy plate quotes.
- Overview
- Specification
- Features & Applications
- FAQs
- Recommended Products
Product Introduction Overview
Kovar 4J29 (also known as ASTM F15 Kovar, UNS K94610, or FeNi29Co17) is a premium vacuum-melted nickel-iron-cobalt controlled expansion alloy engineered for perfect thermal matching with borosilicate hard glass and ceramics. As a leading Kovar 4J29 precision alloy sheet supplier, we provide high-purity sheets with a linear coefficient of thermal expansion (CTE) of 4.6–5.2 × 10⁻⁶/°C (20–400°C) and 5.1–5.5 × 10⁻⁶/°C (20–450°C), ensuring stress-free hermetic glass metal seals across wide temperature ranges.
Our Kovar 4J29 low expansion alloy sheets maintain structural stability down to cryogenic levels and feature a high Curie temperature of 435°C. This makes them the industry-standard material for reliable glass-to-metal sealing in vacuum environments. Available in thicknesses from 0.3 mm to 5 mm, widths up to 1000 mm, and custom lengths, our precision alloy sheets are annealed for optimal formability and oxide layer formation, delivering superior wetting and bonding with hard glass.
Product Features
Our Kovar 4J29 precision alloy sheet stands out with unmatched properties tailored for glass metal sealing applications:
- Matched Thermal Expansion for Borosilicate Glass: Exact CTE compatibility prevents cracking or leakage in hermetic glass-to-metal seals from -80°C to 450°C.
- High-Temperature Stability & Curie Point: Maintains austenitic structure up to 435°C with excellent low-temperature phase stability, ideal for vacuum tubes and electronic packages.
- Superior Oxide Layer Formation: Forms dense Ni/Co oxide film for strong chemical bonding and mercury resistance in discharge devices.
- Excellent Formability & Machinability: Deep-drawing, stamping, and etching friendly; available in annealed or half-hard tempers for easy fabrication.
- Vacuum-Melted Purity: Meets ASTM F15, GB/T 15529, and MIL standards – low outgassing for ultra-high vacuum (UHV) hermetic applications.
- Corrosion & Environmental Resistance: Reliable in harsh conditions, including mercury-containing instruments and aerospace electronics.
These features make our Kovar 4J29 low expansion precision alloy sheets the preferred choice for suppliers and manufacturers worldwide seeking long-term hermetic integrity.
Product Applications
As a trusted Kovar 4J29 precision alloy sheet supplier, our products power critical hermetic glass metal seal applications across industries:
- Electric Vacuum Components: Power tubes, X-ray tubes, microwave tubes, magnetrons, and transistors – primary sealing material for high-airtight structures.
- Semiconductor & Electronics Packaging: Transistor bases, integrated circuit frames, hybrid circuit casings, relays, sealed plugs, and optoelectronic housings.
- Aerospace & Defense: Hermetic connectors, sensors, and vacuum systems requiring controlled thermal expansion alloys.
- Medical & Scientific Instruments: Mercury discharge tubes, cryogenic devices, and precision glass-to-metal sealed instruments.
- Lighting & Consumer Electronics: Vacuum tube envelopes and high-reliability glass seals in lamps and displays.
Whether for borosilicate glass sealing or ceramic-to-metal bonds, Kovar 4J29 low expansion alloy sheets deliver unmatched reliability in demanding hermetic environments.
Product FAQ
Q1: What is Kovar 4J29 alloy and how does it differ from Invar?
Kovar 4J29 (UNS K94610 / ASTM F15) is a nickel-cobalt-iron low expansion precision alloy with ~17% cobalt for precise glass-to-metal sealing CTE matching. Unlike Invar (zero-expansion Ni-Fe alloy), Kovar 4J29 is optimized for hermetic glass metal seals with borosilicate glass up to 450°C.
Q2: What is the thermal expansion coefficient of Kovar 4J29 sheet?
Average CTE: 4.6–5.2 × 10⁻⁶/°C (20–400°C) and 5.1–5.5 × 10⁻⁶/°C (20–450°C) – perfectly matched to hard borosilicate glass for stress-free hermetic sealing.
Q3: How do I prepare Kovar 4J29 alloy sheet for glass sealing?
Anneal in wet hydrogen at 850–900°C, then oxidize in air at 650–700°C to form the ideal thin oxide layer. Our supplier sheets arrive ready for direct fabrication and sealing.
Q4: What sizes of Kovar 4J29 precision alloy sheet are available?
Standard: Thickness 0.3–5 mm, width 100–1000 mm, length up to 2000 mm. Custom cutting, slitting, and polishing available from our precision alloy sheet supplier stock.
Q5: Is Kovar 4J29 suitable for vacuum and cryogenic applications?
Yes – vacuum-melted with low outgassing, excellent low-temperature stability, and hermetic performance down to cryogenic levels, ideal for UHV systems and aerospace glass-to-metal seals.
Q6: Why choose your company as Kovar 4J29 glass metal sealing supplier?
We offer ASTM F15-certified material with full traceability, competitive pricing, fast global delivery, and technical support for hermetic sealing projects. Contact us for custom quotes on Kovar 4J29 low expansion alloy sheets.
