Electroless Nickel Plating (ENP) is that the deposit of a nickel-alloy coating by chemical reduction – while not the electrical current that’s employed in electroplating processes.
The majority of ENP for engineering functions could be a nickel phosphorus deposit containing a pair of 14 phosphorus. Electroless plating prevents corrosion and wear, and may be wont to manufacture composite coatings by suspending powder within the bathtub. linear unit plating creates a good layer no matter the pure mathematics of the surface – in distinction to electroplating that suffers from flux-density problems as associate degree magnetic attraction field can vary thanks to the surface profile and end in uneven depositions. counting on the catalyst, linear unit plating is applied to non-conductive surfaces.
The higher the phosphorus content the larger the corrosion resistance, but the compromise on raised phosphorus content could be a decrease in hardness.
ENP is deposited by reducing nickel ions to aluminiferous nickel with a chemical reducer like atomic number 11 hydrophosphite. Thickness of 25-75m is common, high phosphorus ENP will edge on top of 75m though this will begin to push the boundaries of ENP.
The benefits of electroless nickel plating
ENP offers glorious corrosion resistance to common corrodents like salt water, greenhouse emission, gas and atomic number 1 chemical compound.
High phosphorus deposits of ENP (10-14% phos) is additionally amorphous, which suggests that there are not any grain or section boundaries to form initiation sites for corrosion.
The uniformity of ENP versus electrolytic deposits is additionally advantageous, making a uniformly thick coating across the complete substrate; even in slots, holes and within walls of tube.
Without heat treatment corrosion resistant high phosphorus ENP still provides sensible hardness and wear resistance properties.
ENP offers value-effective answer for applications subject to conditions wherever wear and corrosion are factors; extending service life and providing a lower cost various to corrosion resistant alloys, significantly wherever steel suffers localized corrosion; projection attack or weld corrosion.
ENP offers glorious corrosion protection and uniformity of deposit at the side of sensible hardness. The phosphorus content of the deposit is altered to best match the applying.
Hardness of ENP is raised by heat treatment however this produces a microcracked deposit with reduced corrosion resistance. ENP deposits uniformly, even on complicated shapes, in contrast to electroplating.
How will heat treatment have an effect on Electroless Nickel Plating?
ENP is at its most corrosion resistant in its amorphous section. Heat treatment causes particles of nickel phosphide to precipitate, destroying the amorphous character of the deposit. With high phos ENP deposits this happens at temperatures between 330 and 360C. Adhesion relies on effective cleanup of the substrate. With sensible surface preparation adhesion to steel is between 200-420 MPa. With untarnished steels the bond strength is typically between 160-200 MPa.