ELECTROLESS NICKEL PLATING "KANIGEN®"

Electroless nickel plating known as Kanigen® is a pioneer process. On a commercial scale, in the 1950's General American Transportation Co. came out with Kanigen® which found acceptance as a corrosion-resistance product for tank cars. In 1975 Electro-Coatings. purchased the world wide patent rights, licenses, trademarks and know how for the process know as Kanigen® from General America Transportation Co.

GENERAL INFORMATION ABOUT ELECTROLESS NICKEL PLATING

The electroless nickel plating solution contains a nickel salt and hypophosphite as the reducing agent. Other chemicals are added to the solution to control its pH and act as complexing stabilizing agents. Hydrogen gas and ions is a by-product of the plating process. The reactions will only proceed in the presence of a catalyst. The properly prepared basis metal surface acts as the initial catalyst. Since the nickel deposit is also a catalyst, the reaction continues autocatalytically. Any desired thickness of plating can be obtained as long as the reacting chemicals are replenished.

X-ray diffraction and micrographic inspection have shown Kanigen® to be a super saturated solution of phosphorus in nickel. The as-plated alloy appears to be a series of laminations with a microcrystalline structure composed of gains with an average size of less than 100 Angstroms. The laminar appearance is created by slight variations in the phosphorus content of the solution and for all intents and purposes the structure can be considered amorphous (glass-like). Thermal treatment will transform this metastable laminar structure into a stable equilibrium system consisting of the dispersion of hard nickel phosphides and nickel phases.

KANIGEN® ELECTROLESS NICKEL PLATING PREVENTS CONTAMINATION

Many products such as solvents, although not corrosive to steel, are easily contaminated or discolored by iron oxides. Kanigen® electroless nickel alloy linings prevent rusting of steel surface by moisture and high humidity. The non-toxic nature of electroless plating makes Kanigen® coatings especially suitable for all types of food handling equipment where corrosion and wear resistance is required.

ADHESION OF ELECTROLESS NICKEL

Chemical bonding to metallic substrates is excellent. While there is no standard quantitative measure for metal coatings, reported values of electroless nickel range from 30,000 to 60,000 psi on mild steel and from 23,000 to 29,000 psi on stainless. The high values are generally obtained from an acid plating bath as used in the Kanigen® process. Adhesion to steel and especially to aluminum is improved by baking 300°-400°F after plating. Exposure to low temperatures such as liquefied nitrogen for example, has no effect on the adhesion of the electroless nickel.

Electroless nickel coated steel specimens show no flaking or chipping when pulled to the breaking point in tension. Bending of plated steel bars 180° over a 4t mandrel produces fine cracks in the coating on the tension or outside, parallel to the bending axis with no flaking. Compression on the inside of the bend may cause apparent flaking, but the separation is within the coating, and not at the electroless nickel substrate interface.

KANIGEN® is CORROSION RESISTANT

Kanigen® corrosion resistance is equal to electrolytic nickel and superior to Industrial Hard Chrome. Over steel it can often do the job of expensive stainless steels or clad alloy. The exceptional cost savings alone can be realized. Kanigen® nickel plating is virtually unaffected by petroleum products and most organic liquids, and resists corrosion by many alkalis and weak acids. Electroless nickel corrosion resistance properties.

HARDNESS, WEAR and ABRASION RESISTANCE

Kanigen® has a Rockwell C of about 49 and can be increased to around Rockwell 70 C comparable to Industrial Hard Chrome resulting abrasion resistance is much better than electrolytic nickel. The harden Kanigen® can replace Industrial Hard Chrome.

ELECTRICAL, MAGNETIC and RADATIVE

The electrical resistivity of electroless nickel coatings increase directly with their phosphorus content. As-plated deposits have a resistivity about 10 times larger than for electroplated nickel. By heat treatment above 500°F the resistivity can be stabilized at about 40 microhms/cm/cm².

Data published on the magnetic properties of electroless nickel shown as-plated deposits with over 8% phosphorus to be essentially non-magnetic, but after one hour at 750°F the coercivity is 140 Oersteds. Heat treatment also increases induction properties markedly. Reproducible magnetic films over paramagnetic metals such as aluminum can be obtained, if the phosphorus content is controlled. Relative magnetic susceptibility as-plated is 4% compared to 37.5% for electrolytic nickel.

The solar absorptivity of electroless nickel plating on aluminum averages 0.50, with an emittance of 0.10. Its low outgassing characteristics are essential for aerospace and vacuum applications.

UNIFORMITY

Kanigen® has an excellent thickness uniformity that reproduces the base surface faithfully; no thin spots, no build up on corners or edges, threads, in hole and intricate parts. Because Kanigen® has such remarkable uniformity this electroless nickel plating can be used to salvage evenly worn or mismachined parts.