Electroless nickel-boron deposits were produced on mild steel substrates at a different sodium borohydride (NaBH4) concentration in the plating bath and subjected to heat treatment under argon atmosphere to improve their wear and mechanical properties. Influences of different NaBH4 concentrations in the plating bath on coating's phase structure, composition, hardness tribology properties were evaluated. The surface morphology and chemical composition of Ni-B coatings have been studied by scanning electron microscope (SEM), x-ray diffraction analysis (XRD), respectively. Nanoindentation testing of the depositions was carried out with nanoindentation apparatus equipped with a Berkovich indenter. Tribological properties of Ni-B depositions were investigated with a reciprocating ball-on-disc testing under different loads at room temperature. The wear test was carried out at different loads and the results indicated that the best wear properties of the Ni-B coating could be obtained at NaBH4 concentration of 1 g l(-1).