Crystallization kinetics of electroless Ni-P and Ni-P-Cg composite coating on titanium

Ni-P alloy coatings and Ni-P-Cg composite coatings on titanium surface were obtained by electroless plating method. The crystallization processes of coatings were analyzed by SEM, XRD and EDS. The crystallization kinetics of coatings was studied by differential thermal analysis. The data of non-isothermal kinetics were analyzed and compared by methods of Ozawa, Freeman-Carroll, Achar and Coats-Redfern. The results indicate that characteristic temperature T. and crystallization activation energy E of Ni-P-Cg coating are higher than Ni-P coatings, while the enthalpy value is lower. The kinetic equations were determined, giving crystallization activation energies of Ni-P coating and Ni-P-Cg coating of 308.90 kJ.mol(-1) and 412.99 kJ-mol(-1), respectively, and preexponential factors A of 58.03 s(-1) and 77.84 s(-1), respectively.