Effect of electrolytic nickel coating on fatigue life of iron based powder metal parts

Abstract

Electrolytic coating is one of the methods mainly used to provide corrosion resistance for the powder metal parts. The coatings have strong effects on mechanical properties of coated parts as well as on surface properties. The other factor that affects the mechanical properties of powder metal (P/M) parts is density ratio. In this study the effect of electrolytic coating and density ratio on fatigue life of powder metal iron parts has been investigated. Commercially pure iron powders were pressed under 150, 200 and 250 MPa pressures. Specimens were sintered at 1100◦ C in flowing argon atmosphere for 45 min. Some of the specimens were electrolytic nickel coated. Coated and uncoated specimens were fatigued in rotating bending under the same conditions. Also residual stress analysis was carried out on both kinds of specimens. It had been determined that electrolytic nickel coating increased fatigue life of P/M iron parts. It had also been determined that fatigue life increased with density ratio.