Effect of Heat‐Treatments on Magnetic Properties of Electroless Nickel Alloys

Abstract

Electroless deposits from various ammoniacal and acid formulations were evaluated for their ferromagnetic properties and the effects of artificial aging on these properties. Deposits from ammoniacal solutions were ferromagnetic as deposited. Deposits from acid solutions were nonferromagnetic. After heat‐treatment, all deposits exhibited ferromagnetism through a maximum, the temperature‐time relationship being different for each deposit. This phenomenon appeared to be related to the type of ligand in the solution and to the substrate rather than the phosphorus content of the deposit. Ammoniacal deposits retained magnetism at higher levels after heating for 96 hr at 400°C than any of the acid systems with the pyrophosphate deposit values being higher than citrate deposits. Deposits on aluminum substrates exhibited higher magnetization than on brass substrates or foils separated from substrates.