1.3981 / UNS K94610 – FeNi28Co18 – Alloy K

This Ni-Co alloy, called W. Nr. 1.3981 / Kovar / Alloy K, has two typical applications. 1.3981 / Kovar / Alloy K has the lowest Thermal Expansion Coefficient of all alloys and metals between 20-500 ° C. However, the thermal expansion coefficient is also equal to glass and ceramics. It is an ideal material for glass-metal or ceramic-metal sealing. Many glass sealing systems are manufactured with 1.3981 / Kovar / Alloy K. As the material heats up, the material does not expand, on the contrary, it shrinks and acquires a denser structure. This shrinkage lasts until it reaches the turning point. Thus, 1.3981 / Kovar / Alloy K material can withstand thermal shock and should be preferred where thermal shock resistance is required.

It is melted under vacuum. Applicable norm is ASTM F15. From normal to larger sizes 1.3981 has no phase transformation at -196 ° C.

It consists of 29 percent nickel and 17 percent cobalt. With heat treatment, 1.3981 / Kovar / Alloy K material gains a more durable structure with various hardness and suitable for various different environments. High power transfer valves, camera flashes, transistors, a wide variety of electronic circuit boards are some of the application places that can be mentioned.