Development of a novel method for mechanical plating using ultrasonic vibrations

In this study, we present a novel ultrasonic-based dry mechanical method for armouring or coating metallic surfaces with other metals or ceramic materials. In this method, hard balls (made of stainless steel or ZrO₂) and the metal or ceramic powder are placed into a bowl-shaped resonant chamber that is fixed beneath the surface to be coated. The chamber is set into a high-frequency vibration by using an ultrasonic transducer attached to the chamber bottom. This initiates a chaotic motion and collision of the balls and the powder particles inside the chamber that results in the grinding of the particles, thereby hammering them further into the metallic surface. A series of experiments was conducted using Al plates as substrate and Ti powder as the coating material. The results revealed that the coating efficiency is dependent on several parameters including the number of balls, particle size and ball-to-particle weight ratio. On the whole, the method was found to offer a number of attractive features that enables its use in several practical applications.