Abstract: A surface modification process and apparatus for the electro-spark deposition (ESD) on a workpiece may include mounting a workpiece on a rotationally driven mounting. The contact surface of the workpiece is ESD coated. Ultrasonic vibration is applied to the deposition layer during its crystallization phase. The workpiece may be a resistance spot welding electrode. The apparatus may have a vibrating applicator, ESD power supply, integrated ultrasonic transducer assembly, a work station having a rotational drive and an ultrasonic generator. The ultrasonic generator is connected to the ultrasonic transducer. The ultrasonic transducer assembly and the rotating driving work bench unit are integrated in a single assembly. The workpiece seats on the ultrasonic transducer assembly. The deposition of a surface coating occurs during simultaneous application of electro-spark deposition and ultrasonic vibration.