Process optimization of a hybrid twin-wire arc sprayed composite coating

Hybrid twin-wire arc spraying is a typical process that using two different metal wires as the feeding material. For some occasions the melting point of the two wires is different highly, the higher melting point wire always does not be melted totally and the arc extinguishes frequently. In the present study, a new spraying method using asynchronous feeding for the two wires was put forward, and the arc behavior during spraying of carbon steel and aluminum twin wires was investigated. The results show that, the stability of the hybrid twin-wire arc spraying process was improved significantly when using the asynchronous feeding spray system. Finally, the structure of the Fe-Al composite coating was characterized using a scanning electron microscope and an X-ray diffraction instrument. It is manifested that metallurgical reaction is rarely generated between the anode and cathode for the hybrid twin-wire arc spraying. A mechanically mixed coating is therefore formed, in which the aluminum splats and carbon steel splats are inter-deposited.