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The effect of heat treatment on wear characteristics of nanostructure Ni–B coating on marine bronze

2019; IOP Publishing; Volume: 6; Issue: 10 Linguagem: Inglês

10.1088/2053-1591/ab395d

2053-1591

Y. Shajari, Rouhollah Alizadeh, Z. S. Seyedraoufi, Seyed Hossein Razavi, H Shamakhi,

Nanoporous metals and alloys

In this study, Self-catalytic electroless coating process was applied in order to improve wear resistance and surface hardness of bronze. Through this process, the uniform coating of Ni–B with 7 μm thickness was formed. Microstructural study with the field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD) showed that cauliflower and completely amorphous structure with excellent adhesion was formed on the substrate. Formed Ni–B coating with a microhardness of 788 (HV100) leads to a 40% increase in hardness compare to the substrate. In order to increase the surface hardness, coated samples were heat-treated at temperatures of 310, 410, and 510 °C for 70 min. The hardness of samples increased to 1365 (HV100) after heat treatment and from 410 °C to above hardness decrease. The result of x-ray diffraction showed that at 310 °C Ni–B coating completely was crystallized and Ni2B and Ni3B intermetallic were formed at 410 °C and 510 °C, which led to increasing the surface hardness after heat treatment. The results of a pin on disk wear test showed that the most wear resistance belongs to parts which coated and heat-treated at 410 °C temperature.