The role of calcinated sea shell particles on friction-wear behavior of electroless NiP coating: Fabrication and characterization

The present paper reveals the importance of calcinations of sea shell particles before their use to reinforce NiP composite coatings to achieve low friction and wear resistant property. NiP/calcinated sea shell particles (Cal.SSP) and NiP/non calcinated sea shell particles (SSP) composite coatings have been fabricated on En8 steel using electroless process with various dispersions of SSP and Cal.SSP. Thermo gravimetric analysis (TGA) of sea shell particles was carried out to find the optimum temperature for calcination. A comprehensive study on morphology, structure, hardness and friction - wear property of composite coatings was carried out using scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) with SAED, X-ray diffraction analyzer (XRD), Vickers hardness tester and pin-on-disc apparatus. XRD analysis showed a shift in the peak for SSP and Cal.SSP, indicating a significant improvement in the property of the coating. Phase transformation of Cal.SSP from aragonite to calcite structure showed better friction and wear resistant properties with low hardness in contrast to SSP. The results accordingly demonstrate the friction and wear reducing ability of SSP after phase transformation.