Designation: B 733 – 97Standard Specification forAutocatalytic (Electroless) Nickel-Phosphorus Coatings onMetal 1This standard is issued under the fixed designation B 733; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e ) indicates an editorial change since the last revision or reapproval.This standard has been approved for use byagencies of the Department of Defense.1. Scope1.1 This specification covers requirements for autocatalytic(electroless) nickel-phosphorus coatings applied from aqueoussolutions to metallic products for engineering (functional) uses.1.2 The coatings are alloys of nickel and phosphorus pro-duced by autocatalytic chemical reduction with hypophosphite.Because the deposited nickel alloy is a catalyst for the reaction,the process is self-sustaining. The chemical and physicalproperties of the deposit vary primarily with its phosphoruscontent and subsequent heat treatment. The chemical makeupof the plating solution and the use of the solution can affect theporosity and corrosion resistance of the deposit. For moredetails, see ASTM STP 265 (1)2 and Refs (2) (3) (4) and (5)also refer to Figs. X1.1, Figs. X1.2, and Figs. X1.3 in theAppendix of Guide B 656.1.3 The coatings are generally deposited from acidic solu-tions operating at elevated temperatures.1.4 The process produces coatings of uniform thickness onirregularly shaped parts, provided the plating solution circu-lates freely over their surfaces.1.5 The coatings have multifunctional properties, such ashardness, heat hardenability, abrasion, wear and corrosionresistance, magnetics,...
