4J28 Rod / Bar | Kovar Alloy Rods for Glass-to-Metal Sealing Applications

Product Description

4J28 alloy rod is an iron-nickel-cobalt (Fe-Ni-Co) controlled expansion alloy specially designed for glass-to-metal and ceramic-to-metal sealing applications. It has a linear expansion coefficient that precisely matches hard glass and ceramics, ensuring reliable hermetic sealing.

With stable mechanical strength, excellent machinability, and outstanding sealing performance, 4J28 rods are widely used in electronic packaging, vacuum devices, semiconductor components, and aerospace instruments.

Key Features

• Fe-Ni-Co alloy with controlled thermal expansion

• Excellent sealing performance with glass and ceramics

• Stable mechanical strength at various temperatures

• Easy machining and surface treatment

• Reliable long-term hermeticity

• Available in rods, wires, sheets, and customized forms

Typical Applications

• Glass-to-metal hermetic sealing

• Electronic packaging components

• Vacuum tubes and light bulbs

• Semiconductor packaging bases

• Aerospace and defense devices

• Sensor housings and feedthroughs

Chemical Composition (%)

Physical and Performance Properties

Available Specifications

Packaging & Shipping:

• Packaging:
  Plastic spools, vacuum bags, anti-rust wrapping, and customized labels upon request

• Shipping Methods:
  Air freight, sea freight, express delivery

• Lead Time:

• 
  7–15 working days based on order quantity

Huona (Shanghai) New Material Co., Ltd. Was established in 2008, currently have three divisions: Magnesium Division, Thermal Spray Division and Functional Material Division.

Magnesium Division produces magnesium metal products. Various models of high-quality magnesium alloy plate, magnesium rods, high-purity magnesium, magnesium plate, magnesium die casting, magnesium extrusion profiles and other metal magnesium and deep processing products.

Thermal spray wire Division offers a wide variety of pure metal and metal alloy wires, including nickel-, iron-, aluminum-, and zinc-based wires for thermal spray projects.

Fuctional Material Division supply electronic packaging COMPONENTS(GTMS, CTMS), soft magnetic alloys and bimetal strip.

Our company is certified by ISO9001 quality system and ISO14001 environmental protection system.

Mission Statement

We try our best to understand and utilize information within the environment. With this competency, we assist customers to create added value and contribute to the development of industry and healthy living.

We strive for "Best, " welcome challenges, and are relentless till we deliver products and solutions.