Electro-less plating nickel-phosphorus of low carbon steel using various pretreatments and an external magnetic field

Abstract

Electro-less plating nickel-phosphorus (EPNP) subject to various pretreatments and an external magnetic field, are prepared onto low carbon steel (LCS). The surface hardness (SH), fatigue life (FL) and corrosion behavior (CB) of Ni-P coated are respectively obtained using a nano-indenter and a high strain low cycle fatigue life (HSLCFL) and polarization test. The experimental outcome reveals that LCS substrates that are pretreated using the proposed acid mixture (25% H2SO4 + 5% HCl) roughening and activation allow good Ni-P films to be deposited. In terms of EPNP, as the P content decreases, the SH and FL increase. Specimens that a coated in a Ni–P film using an external magnetic field have better mechanical performance than those that are not produced in an external magnetic field. As the external magnetic field intensity is increased, the film thickness, SH and FL increase, the concentration of P decreases and thin grains are formed on the film surface. The specimens without using an external magnetic field that are coated with a Ni–P film exhibit better resistance to corrosion than the uncoated sample of LCS. However, the Ni–P film that is coated using an external magnetic field has higher SH, so it exhibits increased resistance to corrosion.

Keywords

• Electro-less plating
• Substrate pretreatment
• Magnetic assisted
• Fatigue life
• Corrosion resistance