AMS-2404C, AMS-2505B, AMS-2433B,
Similar to stainless steel in color. Plates uniformly in recesses and cavities (does not build up on edges) sometimes called "Dog-boning". Corrosion resistance is good for coatings over .001" thickness. Electroless nickel is used extensively in salvage of mis-machined parts. Also, for inside dimensions and irregular shapes (where assembly tolerances need uniformity provided by electroless process). Coatings typically used to provide a hard-ductile, wear-resistant and corrosion-resistant surface for operation in service temperatures up to 1000F (538C). Previously Mil-C-26074 was the industry specification.
Please note: The following is per. Mil-C-26074. This specification has been cancelled but, is still used in industry.
Class 1 As coated
Class 2 Steel and other base metals heat treatable to improve hardness.
Class 3 Aluminum and other base metals not heat treatable
Class 4 Aluminum alloy, heat treatable, processed to improve adhesion of the nickel deposit
Grade A .0010" min. Aluminum alloys will be grade A.
Grade B .0005" min.Cu, Ni, Co alloys will be grade B.
Grade C .0015" min. Ferrous alloys will be grade C.
Electroless Nickel - AMS-2404D / AMS-2405B
These AMS specs are similar. Ams- 2404D does not specify the phosphorous content while the
AMS - 2405B says "P" to be 8% max. No specific hardness numbers defined by these two specs on the EN deposit.
AMS-2404D Thickness as specified on drawing. Note: Unless a specific class is specified,
Class 1 shall be supplied.
Class 1 Except for hydrogen embrittlement relief, no postplating thermal treatment.
Class 2 Thermal treatment at 450 F (232 C) or above to harden the deposit.
Class 3 Thermal treatment at 375 F (191 C) to verify adhesion for non-heat treatable aluminum and beryllium alloys.
Class 4 Thermal treatment at 250 F (121 C) to verify adhesion for non-heat treatable aluminum alloys.