The effect of saccharin addition on the mechanical properties and fracture behavior of electroless Ni-Cu-P deposit on Al

In a previous study, the effects of additive saccharin on internal stress, diffusion, and crystallization behaviors of electroless Ni-Cu-P deposits on Al were examined. In this study, tensile test results and microhardness measurements were used to investigate the effect of additive saccharin on the mechanical properties and fracture behavior of electroless Ni-Cu-P deposits on Al. An increase in the saccharin content of the plating solution from 0 to 12 g/L results in nodule growth and void elimination in the deposits. The denser nodules in the deposit also cause a decrease in the tensile stress and reveal the effect of ΔTCE on compressive stress generation. Consequently, the mechanical properties of Ni-Cu-P/Al deposits in terms of microhardness, yield strength, modulus of elasticity, and ultimate tensile strength were improved. The fracture behavior of the deposit changes from transnodular to internodular when the saccharin addition is above 4 g/L.