Development of electroless Ni-P/W nanocomposite coatings and its microhardness

The tungsten nanoparticles of size in the range of 40 to 150 nm with a concentration of 0.25 g/l, are dispersed erratically into an electroless Ni-P matrix for depositions of Ni-P-W nanocomposite coatings on a steel substrate (MS) having grade AISI104. After deposition the thickness of the coatings is found in the range of 10 to 15 micrometer. The scanning electron microscope attached in permutation of energy dispersive spectroscopy furthermore X-ray diffraction techniques were used to analyze surface morphology, elemental symphony and phases of coatings correspondingly. The results obtained by above experimental studies reveal successful synthesis of tungsten nanoparticles as white small globules into an electroless Ni-P matrix. Furthermore the as-deposited Ni-P-W coatings have revealed amorphous structure and while heated platings (300°C) have shown semi-crystalline structure. Further the Ni-P/Ni-P-W coatings were investigated for microhardness by a microhardness tester with respective technique. The results of the microhardness studies substantiate that insertion of tungsten nanoparticles into electroless Ni-P matrix enhances the microhardness. The phase transformation initiation of amorphous nickel is headed toward nickel phosphide and crystalline nickel partially at 300 °C which is responsible for improved microhardness of nanocomposite Ni-P-W electroless coatings.