Materials transfer in electro-spark deposition of TiCp/Ni metal-matrix composite coating on Cu substrate

Electro-spark deposition (ESD) is a microwelding process that utilizes short duration of electrical pulses to deposit electrode materials to a metallic substrate. In this paper, the material transferred from the depositing electrode to the substrate was investigated by producing one deposition each time. Titanium carbide particles/nickel metal-matrix composite (TiC p/Ni MMC) was used as the electrode to coat the copper (Cu) substrate in the static mode and the dynamic mode experiments. The movement of the depositing TiCp/Ni electrode was strictly controlled in static mode experiments. Meanwhile, in dynamic mode experiments, the electrode movement was governed by a spring mechanism. Phenomenological models were developed to detail the events taking place during a single deposition in static and dynamic modes, respectively. The experimental results indicated that the material transferred between the depositing electrode and the substrate is primarily through direct molten-metal to molten-metal contact.