A structural comparison of electroless and electroplated nickel

Nickel that has been electrolessly deposited from a low temperature hypophosphite bath undergoes severe cracking when heat treated. The cracks, which are of two different types, can weaken the nickel deposit and can lead to leak paths in composite structures. In the study reported here the characteristics of thin nickel films were studied by several methods, all of which can be applied to any crystalline thin film: an X-ray method for stress and precipitation sequences; electron microscopy; cross-sectional analysis; kinetic studies. The electroless nickel was compared with a low stress electroplated nickel which does not crack with heat treatment. The electroplated nickel was found not only to have lower stress than the electroless nickel but also to have no significant secondary phase precipitation.