Abstract: A process for plating aluminum alloy substrates (10), such as 390 aluminum alloy pistons (12), with iron comprises (a) plating on the aluminum substrate a layer of zincate from a zincate bath; (b) plating on the zincate layer a layer (14) of nickel from an electroless nickel bath; (c) plating on the nickel layer a layer (16) of iron from an iron ammonium sulfate bath; and (d) plating on the iron layer a layer (18) of tin from an alkaline tin bath. During the electroless plating, the zincate layer, which protects the underlying aluminum against oxidation, is sacrificed. All of these baths are environmentally much safer than cyanide and chloride. They are also cost effective and can be utilized in a totally closed loop plating system.

Abstract: A process for plating aluminum alloy substrates such as aluminum pistons with an iron-cobalt alloy comprising the steps of (a) plating on the aluminum alloy substrate a thin layer of nickel from an electroless nickel bath; and (b) plating on the nickel layer a layer of iron-cobalt alloy from an iron-cobalt electroplating bath. The iron-cobalt layer is not subject to the corrosion problems inherent in a substantially pure iron-plated coating nor the excessive hardness, costliness, and environmental concerns related to the use of nickel as the primary plated layer. The iron-cobalt electroplating bath is cost-effective and can be utilized in a totally closed loop plating system. The resulting iron-cobalt plated, aluminum alloy parts evidence good adhesion, wear, thermal conductivity, and corrosion-resistant properties.

Abstract: A process for plating aluminum alloy substrates (10), such as 390 aluminum alloy pistons (12), with iron comprises (a) plating on the aluminum substrate a layer of zincate from a zincate bath; (b) plating on the zincate layer a layer (14) of nickel from an electroless nickel bath; (c) plating on the nickel layer a layer (16) of iron from an iron ammonium sulfate bath; and (d) plating on the iron layer a layer (18) of tin from an alkaline tin bath. During the electroless plating, the zincate layer, which protects the underlying aluminum against oxidation, is sacrificed. All of these baths are environmentally much safer than cyanide and chloride. They are also cost effective and can be utilized in a totally closed loop plating system.

Abstract: Aluminum and aluminum alloy parts, such as pistons, are electroplated with iron employing a ferrous electroplating solution. The solution comprises (a) ferrous iron having a concentration ranging from about 0.65 to 2.0 Moles of Fe.sup.2+ per liter of solution; (b) at least one anion selected from the group consisting of sulfamate and ammonium sulfate and associated with the Fe.sup.2+ ions; (c) a reducing agent, such as ascorbic acid, in an amount sufficient to prevent oxidation of Fe.sup.2+ to Fe.sup.3+ ; (d) Cl.sup.- anion in an amount sufficient to promote dissolution of the iron anode; and (e) a wetting agent in an amount sufficient to prevent pitting of the aluminum cathode. The ferrous electroplating bath of the present invention permits plating of relatively thick layers of iron on aluminum, typically on the order of about 0.6 to 2 mils (0.0015 to 0.0051 cm), with a microhardness of at least about 40 (Rockwell C scale).

Abstract: A process for plating aluminum and aluminum alloy substrates, such as 390 aluminum alloy pistons, with iron comprises (a) cathodically activating the aluminum-containing substrate in an acid bath and (b) plating iron from an iron sulfate-containing bath,