Kovar, also known as Alloy V29-17, UNS K94610, DIN 1.3981, ASTM F-15, A54-301, and NILO K, is a nickel-cobalt-iron alloy known for its low coefficient of thermal expansion and its compatibility with glass and ceramics. These properties make it ideal for applications requiring a stable seal between metal and glass or ceramics, often used in electronic and electrical applications.

Kovar is composed of approximately 29% cobalt, 17% nickel, and the remainder iron. This specific composition ensures minimal thermal expansion and makes Kovar suitable for applications where dimensional stability and thermal compatibility are essential.

Kovar Sheet | Plate

Kovar sheets and plates are available in various thicknesses and sizes, providing high dimensional stability and flatness. These products are utilized in applications where precise dimensional control is needed, such as in the manufacturing of hermetic seals, electronic components, and other precision-engineered parts.

Kovar Round Bar | Rod

Kovar round bars and rods are available in a range of diameters and lengths, suitable for machining into custom parts. These components are crucial for applications that require precise machining and dimensional accuracy, often found in high-tech and aerospace industries.

Kovar Strip | Coil

Available in flexible strips and coils, Kovar is used for applications where materials need to be bent, formed, or used continuously. These forms are valuable in the production of electrical contacts, connectors, and other components where flexibility and dimensional stability are critical.

Kovar Applications

• Power tubes, microwave tubes, transistors, diodes and hybrid packages.

Kovar Properties

• Coefficient of Thermal Expansion: Approximately 5.0 x 10^-6 /°C, which is low compared to many metals, making Kovar suitable for applications where thermal expansion must be closely controlled.
• Density: Around 8.2 g/cm³, providing a balance of strength and weight for various applications.
• Thermal Conductivity: Approximately 14-16 W/m·K, offering moderate thermal conductivity while maintaining dimensional stability.
• Magnetic Properties: Kovar is generally magnetic, which can be relevant in applications where magnetic properties are a factor in component design.
• Mechanical Properties: Kovar provides good mechanical strength and ductility, designed to maintain precise dimensions under thermal stress.

Machining Kovar

• Cutting: Kovar can be cut using conventional tools. Sharp tools and appropriate cutting speeds are essential to avoid excessive wear and achieve clean cuts.
• Drilling: For drilling Kovar, high-speed steel (HSS) drills or carbide-tipped bits are recommended. Proper lubrication and cooling help maintain tool life and ensure accurate holes.
• Turning: Carbide inserts are preferred for turning Kovar. Maintaining a steady feed rate and managing heat buildup are crucial to preserve dimensional accuracy.
• Milling: Kovar can be milled using conventional techniques. Carbide end mills and cooling fluids should be used to manage heat and prevent dimensional changes during milling.
• Grinding: Grinding Kovar is effective for achieving tight tolerances and fine finishes. Using appropriate abrasive wheels and coolant helps achieve the desired surface finish while maintaining dimensional stability.

Chemical Composition

• Carbon (C): Max 0.04%
• Manganese (Mn): Max 0.50%
• Silicon (Si): Min 0.20%
• Nickel (Ni): Min 29%
• Iron (Fe): Min 53%
• Cobalt (Co): Max 17%
• Aluminum (Al): Max 0.10%
• Chromium (Cr): Max 0.20%
• Magnesium (Mg): Max 0.10%
• Zirconium (Zr): Max 0.10%
• Titanium (Ti): Max 0.10%
• Copper (Cu): Max 0.20%
• Molybdenum (Mo): Max 0.20%