Analysis on mechanical and microstructural properties of electrodeposited Ni-TiN-AlN/Si3N4 composite coatings

The parameter such as reinforced particles plays a role in controlling the microstructure and eventually influences the mechanical properties of the composite coating. The microstructure strength of composite coating come from phase combination of the matrix and its reinforcement. This study described the effect of the electrodeposition process parameters of Si3N4 particle concentration on the Ni-TiN-AlN/Si3N4 composite coatings. Therefore, the experiment was performed by varying Si3N4 particles concentration in range of 0.2, 0.4 and 0.6 g/L in electrodeposition process. The coating morphology and crystal structure were characterized by mean of Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD), respectively while the coating microhardness was tested by using Vickers hardness test. The calcultations were performed to analyze the coating stress from XRD data and presented its relation with the coating microhardness. The analysis results displayed that the uniform surface morphology of composite with the evolution of nitride particle aggregation was observed at various S3N4 particles concentration. In general, the uniformity morphology was due to the refinement of Ni crystallite size. The crystal structure was noticed prominently by Ni, TiN and AlN grains while Si3N4 grain was not observed due to its amorphous nature. In general, the increase of composite microhardness, as increasing Si3N4 concentration was attributed by the reducing Ni crystallite size lead to the increase of coating residual stress.