Ni-Mn 전착층의 기계적 성질에 미치는 공정조건의 영향

Abstract

Nickel electrodeposition from sulfamate bath has several benefits such as low internal stress, high currentdensity and good ductility. In nickel deposited layers, sulfur induces high temperature embrittlement, asNi-S compound has a low melting temperature. To overcome high temperature embrittlement problem, addingmanganese is one of the good methods. Manganese makes Mn-S compound having a high melting temperatureabove 1500℃. In this work, the mechanical properties of Ni-Mn deposited layers were investigated by using various processvariables such as concentration of Mn(NH2SO3)2, current density, and bath temperature. As the Mn contentof electrodeposited layers was increased, internal stress and hardness were increased. By increasing currentdensity, internal stress increased, but hardness decreased. With increasing the bath temperature from 55to 70℃, internal stress of Ni deposit layers decreased, but hardness didn't change by bath temperature. It was likely that eutectoid manganese led to lattice deformation, and the lattice deformation increased hardnessand internal stress in Ni-Mn layers. Increasing current density and decreasing bath temperature wouldincrease a mount of H2 absorption, which was a cause for the rise of internal stress.