Abstract: A method of preparing metal surfaces for thermally applied coatings by electrical discharge, which method controllably provides greater roughness for increased mechanical coating adhesion, avoids carbon deposits and is more economical to use. The method comprises melting and rapidly solidifying globules of the metal surface by spark erosion, the spark erosion occurring by incidence of an electrical discharge between an electrode and the metal surface closely spaced thereto, the spacing having an electrolyte with plasma forming capabilities, the discharge resulting from application of an electrical current to the electrode with a DC voltage in the range of 60-85 volts and amperage in the range of 50-110 amps, the current being pulsed on for periods of 150-300 micro seconds per spark.