Modelling and optimisation of ENi-P-TiO2 coatings synthesised with Zwitterionic surfactant on naval grade AH36 Steel

There are two primary objectives of this study to design the titanium-based novel ENi-P composite coatings on naval grade AH36 steel through Taguchi DOE with the addition of Zwitterionic surfactant and identify the most significant factor which contributes to the enhancement of microhardness in the fabricated coatings. The L9 composite coatings are developed by varying bath temperature, pH, wt% of C14-SB and TiO2 nanoparticles in the electroless bath. Each coatings elemental composition is investigated using SEM and EDAX
analysis. XRD peaks are matched with the peaks of Nickel, Phosphorous and Titanium contents in the deposits. The ANOVA and the S/N ratio were deduced and utilised to formulate the optimal combination of parameters for enhancing microhardness in the coatings. The predicted optimal coatings were validated with a confirmation run and achieved 54.66% microhardness enhancement compared with the initial condition and 196.4% improvement achieved with the substrate material AH36 steel. This experimental work proves its first kind of titanium-based ENi-P coating over the marine grade AH36 steel substrate closely associated with defence
applications.