Overview

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.

Limiting Chemical Composition, %

Nickel.............................................................................................................................................................................................29.50

Iron.................................................................................................................................................................................................53.00

Coblat.............................................................................................................................................................................................17.00

Physical Constants

Tensile Properties

Corrosion Resistance

NILO alloy K is a nickel-iron-cobalt alloy with good corrosion resistance. Its corrosion resistance mainly comes from the main components of the alloy and the special heat treatment process.

First, nickel is the main matrix element of NILO alloy K, which provides excellent corrosion resistance. The presence of nickel allows the alloy to remain stable in a variety of corrosive environments and resist the erosion of corrosive media.

Secondly, the addition of iron and cobalt further improves the corrosion resistance of the alloy. Iron and cobalt form a dense oxide film that prevents further oxidation and corrosion. This oxide film plays a protective role and effectively isolates the contact between the alloy and the external corrosive medium.

In addition, NILO alloy K has undergone a special heat treatment process to further enhance its corrosion resistance. Through proper heat treatment, the element distribution in the alloy is more uniform, forming a more dense oxide film, and improving the resistance to corrosive media.

It is important to note that although NILO alloy has good corrosion resistance, corrosion is still possible when exposed to highly corrosive media or environments. Therefore, in the process of use, it is necessary to evaluate its corrosion resistance according to the specific situation, and take the necessary protective measures, such as selecting the appropriate coating or passivation treatment method, to extend its service life and ensure its stable performance.

Thermal Treatments

The alloy is normally used in the annealed condition, attained by heating, preferably in hydrogen or cracked ammonia, to 850-1000°C (1560-1830°F).

Decarburization to prepare for glass-to-metal sealing is usually carried out in an atmosphere of wet hydrogen at 900- 1050°C (1650-1920°F) for 1 hour. For seals requiring a metal oxide interface, the alloy can be oxidized by heating in air to temperatures in the 600-1000°C (1110-1830°F) range, depending on the thickness of oxide film required.

Available  Forms