Composition, mechanical properties, and structure of electrodeposited cobalt–iron alloys

Abstract

Electrodeposited films of cobalt–iron traditionally have been thought of in terms of their magnetic properties. The current investigation, however, has demonstrated that the mechanical properties of bulk coatings of cobalt–iron alloys can be equally attractive. Bulk coating (> 100 μ) of cobalt–iron have been electrodeposited in the concentration range of 1%–12.6% Fe as a function of cathodic current density (1–10 A/dm2), electrolyte temperature (60–90 °C) and ferrous concentration in the electrolyte (0.5–5.0 g/liter Fe++). Microstructure–mechanical property relationships, including yield strengths, ultimate tensile strengths and microhardnesses, have been determined for these materials after a 15 min, 482 °C (900 °F) stress relief anneal. Room temperature yield strengths as high as 102 kg/mm2 (145 000 psi) and ultimate tensile strengths of up to 135 kg/mm2 (192 000 psi) have been obtained. The general trends indicate that lower electrolyte temperatures, and higher iron contents yield coatings with greater strength.