NILO alloy K (UNS K94610/W. Nr. 1.3981), a nickel-iron-cobalt alloy containing approximately 29% nickel and 17% cobalt. Its thermal expansion characteristics match those of borosilicate glasses and alumina type ceramics. It is manufactured to a close chemistry range, yielding repeatable properties which make it eminently suitable for glass-to-metal seals in mass production applications, or where reliability is of paramount importance.

The magnetic properties of Nilo alloy K are governed basically by its composition and  by the heat treatment applied.

The composition of the alloy generally decides the optimum values of the magnetic properties, such as permeability, coercive force and hysteresis loss. The heat treatment given to the alloy will vary these properties between the worst and optimum levels.

The temperature is effective in changing permeability and other properties. For example, coercive force and residual induction will almost invariably decrease with increasing temperature, when no phase change occurs. It also follows that hysteresis decreases with increasing temperature.