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4J42 Wire for Glass-to-Metal and Ceramic Sealing Systems

4J42 Wire for Glass-to-Metal and Ceramic Sealing Systems

Brand Name:DLX   Place of Origin:China Jiangsu    Delivery Time:7-15 Days
Certification:CE,ROHS   Supply Ability:500 tons per month
Payment Terms:L/C,T/T,Western Union,MoneyGram

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Product Introduction

4J42 wire, also known as an iron-nickel controlled expansion alloy, is one of the most widely used materials in precision sealing systems, particularly in glass-to-metal and ceramic-to-metal applications. At DLX Alloy, we specialize in producing high-quality 4J42 wire with exceptional consistency, ensuring compatibility, reliability, and performance in demanding sealing environments such as electronic vacuum devices, microelectronic packages, and sensors.

For more details, pls directly contact us.

4J42 is primarily composed of approximately 42% nickel and the remainder iron, with trace elements carefully controlled to maintain uniform thermal expansion. This specific nickel-to-iron ratio gives the alloy a coefficient of thermal expansion (CTE) that closely matches that of hard glass and certain ceramics. This property makes it ideal for hermetic sealing, where mismatched expansion rates between metal and glass can lead to cracks or leaks during temperature changes.

Key Characteristics:

  • Stable thermal expansion coefficient

  • Excellent mechanical strength and ductility

  • High dimensional stability under varying temperatures

  • Compatible with both glass and ceramic sealing systems

  • Good corrosion and oxidation resistance under vacuum or controlled atmospheres

At DLX Alloy, our 4J42 wire is refined through vacuum melting and precision rolling processes, ensuring uniform grain structure, purity, and dimensional accuracy that directly impact sealing quality and electrical performance.

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

-

1J36

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

-

1J79

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

-

For more details, pls directly  contact us.

4J42 wire plays a vital role in several industries where reliable sealing and stability are essential:

  • Glass-to-Metal Sealing: Used in electronic tubes, light bulbs, and vacuum switches to prevent gas leakage.

  • Ceramic Sealing: Found in high-frequency devices, microwave components, and hermetic connectors.

  • Microelectronic Packaging: Offers thermal compatibility with glass or ceramic substrates to prevent stress cracking.

  • Sensor Components: Ideal for temperature sensors and magnetic shielding applications.

  • Aerospace and Defense: Used in precision electronic modules that require long-term thermal stability.

Industry Trends

As electronics continue to miniaturize and operate under higher thermal and mechanical stress, materials like 4J42 have gained renewed attention. The global demand for controlled expansion alloys is being driven by the growth of microelectromechanical systems (MEMS), semiconductor packaging, and advanced optics.

Moreover, with the shift toward high-reliability aerospace and satellite systems, sealing alloys that maintain integrity under extreme conditions are becoming crucial. In response, manufacturers like DLX Alloy are optimizing alloy purity and surface finish to enhance sealing performance, reduce micro-defects, and ensure uniform bonding.

Property 4J42 (Ni42Fe) Kovar Equivalent (Ni29Fe17Co) 304 Stainless Steel
Nickel Content (%) ~42 ~29 8–10
Coefficient of Expansion (×10⁻⁶/°C) 5.0–5.5 5.0–5.5 17.3
Melting Point (°C) 1450 1450 1400
Electrical Resistivity (μΩ·m) 0.49 0.48 0.73
Density (g/cm³) 8.1 8.3 7.9
Sealing Compatibility Glass/Ceramic Glass/Ceramic Poor
Oxidation Resistance Moderate Good Excellent

While other alloys offer certain advantages, 4J42 strikes an ideal balance between expansion control, cost efficiency, and bonding reliability, making it a top choice for mass production sealing applications.

DLX Alloy Advantages

At DLX Alloy, we take pride in our deep metallurgical expertise and modern manufacturing capabilities. Our production of 4J42 wire focuses on three core strengths:

  1. Precision Control:
    We maintain strict control over nickel-to-iron ratios through vacuum melting, ensuring consistent expansion performance across batches.

  2. Superior Surface Finish:
    Our precision drawing and annealing lines produce smooth, oxide-free wire surfaces that promote strong adhesion during glass or ceramic sealing.

  3. Customization Options:
    DLX Alloy provides 4J42 wire in various diameters, tensile strengths, and surface finishes (bare, annealed, or oxide-coated) to meet different application requirements.

  4. Testing and Certification:
    Every batch is inspected using advanced non-destructive testing, dimensional analysis, and microstructure evaluation to ensure compliance with international standards.

  5. Reliable Supply Chain:
    With stable raw material sourcing and fast delivery systems, we help customers maintain seamless production and minimize downtime.

The demand for sealing alloys like 4J42 continues to grow due to their critical role in vacuum electronics, semiconductor packages, and emerging green technologies such as electric vehicle sensors. As global electronics manufacturing shifts toward miniaturization and reliability, 4J42 wire will remain a cornerstone material for hermetic and structural sealing.

DLX Alloy continues to invest in advanced melting and testing technologies to improve the consistency and mechanical performance of 4J42 wire. Our goal is to provide not just a product, but a dependable foundation for our customers’ high-precision applications.



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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1. What makes 4J42 wire suitable for glass-to-metal sealing?
Its thermal expansion closely matches glass, reducing the risk of cracks or leaks during temperature fluctuations.

2. What is the main composition of 4J42 wire?
It contains about 42% nickel and the remainder iron, with minor trace elements for fine-tuning expansion.

3. Can 4J42 wire be used for ceramic sealing?
Yes, it is often used for ceramic-to-metal seals in microelectronic and vacuum applications.

4. What are the common forms available?
Wire, strip, rod, and sheet, depending on application needs.

5. Does DLX Alloy offer customized diameters?
Yes, we provide a wide range of diameters and mechanical states based on customer specifications.

6. How does DLX Alloy ensure consistent quality?
We use vacuum melting, precision rolling, and strict inspection systems for every batch.

7. Is 4J42 corrosion resistant?
It offers moderate corrosion resistance, suitable for sealed environments or protective coatings.

8. What industries commonly use 4J42 wire?
Electronics, aerospace, telecommunications, and precision instruments.

Previous article：4J42 Nickel-Iron Alloy Wire for Controlled Expansion Applications Next article：4J45 Controlled Expansion Alloy Wire for Semiconductor Packaging

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