Nilo K is a Nickel-Iron-Cobalt, controlled expansion alloy with 29% Nickel.

NILO K (UNS K94610 / W, 1.3981) is a nickel-iron-cobalt alloy containing about 29% nickel and 17% cobalt. Thermal expansion properties are suitable for borosilicate glasses and alumina type ceramics. It is produced according to a comprehensive range of chemicals and has reproducible properties, and this is particularly suitable for glass-to-metal seals in mass production applications or reliability is crucial. The magnetic properties of Nilo K are mainly governed by the composition and the heat treatment applied. The composition of the alloy generally determines the optimum values ​​of magnetic properties such as permeability, coercive power and hysteresis loss. The heat treatment given to the NILO K alloy will change these properties between the worst and optimum levels. It is effective in changing the heat permeability and other properties. For example, when no phase change occurs, the force of force and residual induction will almost always decrease with increasing temperature. Also, hysteresis decreases as temperature increases

Kovar Alloy is also a controlled expansion alloy known as ASTM F-15, NILO K, Pernifer 2918, Rodar and Dilvar P1. It is a Nickel Iron alloy with 29% Nickel, 17% Cobalt and the remaining balance is Iron. The expansion properties of Kovar match both borosilicate (or Pyrex) glasses and alumina ceramics, which is one of the most popular of controlled expansion alloys for hermetic sealing applications. Kovar is manufactured to provide good properties for machining and deep drawing and is a non-porous product. Kovar is used in applications such as power tubes, microwave tubes, transistors, diodes, hybrid packages and other scientific tools.