INTERFACE WITH SUBSTRATES OF HIGH-PHOSPHORUS ELECTROLESS NIP AND NICUP DEPOSITED FROM NONAMMONIA ALKALINE-SOLUTIONS

Electroless NiP and NiCuP alloys with high phosphorus content (11 to 1 3 weight percent) are plated from nonammonia alkaline baths onto alumi num and iron substrates. Energy-dispersive spectroscopy analysis is us ed to examine the chemical composition of the coatings. Scanning Auger electron spectroscopy is applied to study elemental profiles and the interface with the substrates. The zincate layer transformation at the interface with the aluminum substrate is investigated at two bath tem peratures. Nickel, phosphorus, and copper concentration is plotted aga inst the coating thickness to examine the chemical homogeneity and to obtain information about the mechanism of electroless ternary alloy fo rmation on both types of substrates.