Effect of NaBH4 concentration on hardness and microstructural properties of electroless deposited St-37 steel

In this study, electroless Ni-B depositions were achieved on the St-37 steel substrates at different NaBH4 concentrations and 950 oC 1 hour. Electroless deposited samples had a cauliflower-like surface texture that makes lubricating naturally as concentration increased, grain size decreases in microstructure. XRD spectra of sample showed partial amorph region together with crystalline region. Microhardness testing performed microhardness tester under load 25 g an indentation time 10 s. The highest hardness value was obtained prepared 1.4 g/l concentration.