The 4J29 Kovar Alloy Plate, also known as Ni29Fe17Co, is a high-performance material engineered for glass-to-metal and ceramic sealing applications. Its unique combination of controlled thermal expansion, mechanical strength, and corrosion resistance makes it ideal for hermetic sealing, electronic packaging, and high-precision instrumentation.
At DLX Alloy, we specialize in producing premium 4J29 plates with consistent chemical composition, tight dimensional tolerances, and superior surface finish, ensuring reliable performance in critical assemblies where thermal expansion mismatches can cause failure.
4J29, commonly referred to as Kovar, is a nickel-iron-cobalt alloy designed to exhibit a coefficient of thermal expansion (CTE) closely matching borosilicate glass and ceramics. This makes it particularly valuable for hermetic sealing, electronic packaging, and vacuum devices.
Key material properties include:
Controlled thermal expansion compatible with glass and ceramic substrates
Excellent mechanical strength and ductility
Corrosion and oxidation resistance for long-term durability
High processability for precision forming, cutting, and machining
Stable magnetic and electrical properties
DLX Alloy uses vacuum induction melting, precision rolling, and controlled annealing to produce 4J29 plates with uniform microstructure, minimal internal stress, and high-quality surface finishes, essential for sealing and electronic applications.
Alloy Composition Table
Alloy Grades | C | S | P | Mn | Si | Ni | Cr | Co | Mo | Cu | Al | Nb | Fe | Other Elements |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1J06 | 0.04 | 0.015 | 0.015 | ≤0.10 | ≤0.15 | - | - | - | - | - | 5.5-6.5 | - | Rest | - |
1J12 | 0.03 | 0.015 | 0.015 | ≤0.10 | ≤0.15 | - | - | - | - | - | 11.6-12.4 | - | Rest | - |
1J17 | 0.03 | 0.02 | 0.02 | ≤0.60 | ≤0.20 | - | 15.5-16.5 | - | - | - | - | - | Rest | - |
1J18 | 0.03 | 0.02 | 0.02 | 0.3-0.7 | ≤0.15 | 0.5-0.7 | 17-18.5 | - | - | - | - | - | Rest | Ti: 0.3-0.7 |
1J22 | 0.04 | 0.02 | 0.02 | ≤0.3 | ≤0.3 | ≤0.5 | - | 49-51 | - | ≤0.2 | - | - | Rest | V: 0.8-1.8 |
1J30 | 0.04 | 0.02 | 0.02 | ≤0.40 | ≤0.30 | 29.5-30.5 | - | - | - | - | - | - | Rest | - |
0.03 | 0.02 | 0.02 | ≤0.60 | ≤0.20 | 35.0-37.0 | - | - | - | - | - | - | Rest | - | |
1J38 | 0.03 | 0.05 | 0.02 | 0.3-0.6 | 0.15-0.3 | 37.5-38.5 | 12.5-13.5 | - | - | - | - | - | Rest | - |
1J46 | 0.03 | 0.02 | 0.02 | 0.6-1.1 | 0.15-0.3 | 45.0-46.5 | - | - | - | ≤0.2 | - | - | Rest | - |
1J50 | 0.03 | 0.02 | 0.02 | 0.3-0.6 | 0.15-0.3 | 49-50.5 | - | - | - | ≤0.2 | - | - | Rest | - |
1J51 | 0.03 | 0.02 | 0.02 | 0.3-0.6 | 0.15-0.3 | 49-50.5 | - | - | - | ≤0.2 | - | - | Rest | - |
1J54 | 0.03 | 0.02 | 0.02 | 0.3-0.6 | 1.1-1.4 | 49.5-51 | 3.8-4.2 | - | - | ≤0.2 | - | - | Rest | - |
1J76 | 0.03 | 0.02 | 0.02 | 0.3-0.6 | 0.15-0.3 | 75.0-76.5 | 1.8-2.2 | - | - | 4.8-5.2 | - | - | Rest | - |
1J77 | 0.03 | 0.02 | 0.02 | 0.3-0.6 | 0.15-0.3 | 75.5-78 | - | - | 3.9-4.5 | 4.8-6.0 | - | - | Rest | - |
0.03 | 0.02 | 0.02 | 0.6-1.10 | 0.3-0.5 | 78.5-80.0 | - | - | 3.8-4.1 | ≤0.2 | - | - | Rest | - | |
1J80 | 0.03 | 0.02 | 0.02 | 0.6-1.10 | 1.1-1.5 | 79.0-81.5 | 2.6-3.0 | - | - | ≤0.2 | - | - | Rest | - |
1J85 | 0.03 | 0.02 | 0.02 | 0.3-0.60 | 0.15-0.3 | 79.0-81.0 | - | - | 4.8-5.2 | ≤0.2 | - | - | Rest | - |
1J87 | 0.03 | 0.02 | 0.02 | 0.3-0.6 | ≤0.3 | 78.5-80.5 | - | - | 1.6-2.2 | - | - | 6.5-7.5 | Rest | - |
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4J29 alloy plates are widely used in applications where dimensional stability and hermetic sealing are critical:
Glass-to-metal sealing: hermetic enclosures, feedthroughs, and connectors
Ceramic sealing: substrates and packaging for high-reliability electronics
Electronic packaging: semiconductor and sensor assemblies requiring thermal matching
Vacuum devices: tubes, electronic assemblies, and hermetic enclosures
Optical devices: precision frames and housings for lenses and laser systems
Aerospace and scientific instrumentation: temperature-sensitive devices requiring stable performance
DLX Alloy offers customized plate thicknesses, dimensions, and surface finishes, allowing seamless integration into complex assemblies requiring tight tolerances and long-term reliability.
The demand for Kovar alloy plates is increasing due to the growth of aerospace, semiconductor, optical, and precision instrumentation industries, all of which require materials with stable thermal expansion and excellent mechanical properties.
Key trends impacting 4J29 usage include:
Miniaturization of electronics, where even small thermal expansion mismatches can cause stress or component failure
Hermetic semiconductor packaging, requiring materials that closely match CTEs of glass or ceramic substrates
High-reliability optical and aerospace devices, needing precise dimensional control under thermal cycling
Scientific instrumentation, requiring minimal thermal drift for accurate measurements
DLX Alloy addresses these industry needs by producing 4J29 plates with tight chemical control, uniform microstructure, and precise dimensional tolerances, ensuring consistent performance in high-precision applications.
| Property / Alloy | 4J29 (Kovar) | 4J33 | 4J36 (Invar) | 4J42 |
|---|---|---|---|---|
| Nickel Content (%) | 29 | 33 | 36 | 42 |
| Cobalt Content (%) | 17 | 0 | 0 | 0 |
| CTE (20–100°C, ×10⁻⁶/°C) | 5.0 | 3.0 | 1.2 | 2.0 |
| Density (g/cm³) | 8.2 | 8.0 | 8.1 | 8.1 |
| Yield Strength (MPa) | 250–350 | 220–320 | 250–350 | 300–400 |
| Thermal Stability | Moderate | Good | Excellent | Very Good |
| Corrosion Resistance | Moderate | Good | Good | Good |
| Typical Applications | Glass-to-metal and ceramic sealing | Vacuum devices, sensors | Precision instruments, aerospace | Low-expansion frames, sealing |
| Processability | Moderate | Good | Excellent | Good |
The table highlights that 4J29 offers a balanced combination of CTE compatibility, mechanical strength, and sealing performance, making it ideal for hermetic glass-to-metal and ceramic applications.
Why Choose DLX Alloy
DLX Alloy combines advanced metallurgical expertise with precision production technology to deliver superior 4J29 plates.
Our advantages include:
Vacuum induction melting for chemical homogeneity and minimal impurities
Precision rolling and controlled annealing to reduce internal stress and optimize microstructure
Strict dimensional control for reliable integration into glass-to-metal and ceramic assemblies
Custom surface finishes suitable for plating, coating, or sealing
Comprehensive testing including CTE, mechanical, and chemical properties
These advantages ensure that DLX 4J29 plates are consistent, durable, and reliable, meeting the demands of high-precision electronics, optical devices, and aerospace applications.
DLX Production and Quality Assurance
DLX Alloy employs state-of-the-art production facilities and rigorous quality control:
Vacuum induction melting to ensure chemical uniformity
Precision rolling and controlled annealing for uniform thickness and stress relief
Dimensional inspections for flatness, thickness, and surface finish
CTE and mechanical property verification for every batch
DLX Alloy also provides customized 4J29 plates tailored to specific applications, ensuring seamless integration into high-precision sealing, optical, and electronic systems.
Sustainability and Market Outlook
The market for Kovar alloy plates continues to grow due to the increasing use of hermetic electronic packaging, optical devices, and aerospace applications. Components require materials with stable dimensions under thermal cycling, which is critical for long-term performance.
DLX Alloy incorporates sustainable production practices, including recycling scrap metal, minimizing waste, and optimizing energy consumption during melting and rolling. With the rise of high-precision electronics and aerospace devices, DLX is positioned to supply high-quality, reliable 4J29 plates to global markets.
4J29 Kovar Alloy Plate is an essential material for glass-to-metal sealing, ceramic sealing, and high-reliability electronic and optical devices, offering controlled thermal expansion, mechanical stability, and corrosion resistance. Its properties ensure reliable performance where thermal fluctuations could otherwise compromise functionality.
DLX Alloy guarantees high-quality 4J29 plates with consistent chemical composition, precise dimensional control, and superior thermal performance, supporting customers in electronics, aerospace, and optical industries worldwide.
About Us:
Our 12,000㎡ factory is equipped with complete capabilities for research, production, testing, and packaging. We strictly adhere to ISO 9001 standards in our production processes, with an annual output of 1,200 tons. This ensures that we meet both quantity and quality demands. Furthermore, all products undergo rigorous simulated environment testing including high temperature, high pressure, and corrosion tests before being dispatched, ensuring they meet customer specifications.
For all our clients, we offer timely and multilingual after-sales support and technical consulting, helping you resolve any issues swiftly and efficiently.
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FAQs:
1. What is the composition of 4J29?
It contains approximately 29% nickel, 17% cobalt, and 54% iron, designed for thermal expansion compatibility with glass and ceramics.
2. What is the main benefit of 4J29 plates?
Controlled thermal expansion ensures hermetic sealing and dimensional stability for electronic and optical applications.
3. Which industries use 4J29 plates?
Electronics, optical devices, aerospace, sensors, and semiconductor packaging.
4. How does 4J29 compare to 4J33?
4J29 includes cobalt for better glass-to-metal CTE matching, while 4J33 offers slightly lower thermal expansion for general sealing applications.
5. Can DLX Alloy customize plate sizes and thickness?
Yes, DLX provides tailored dimensions, thicknesses, and surface finishes for precise assembly needs.
6. Is 4J29 suitable for ceramic sealing?
Yes, its CTE closely matches ceramics, preventing cracks or stress during thermal cycling.
7. What heat treatment improves 4J29 properties?
Controlled annealing reduces internal stress and enhances dimensional stability.
8. Does DLX Alloy provide testing reports?
Yes, every batch includes CTE, mechanical, and chemical analysis documentation.
