CATHODIC ARC DEPOSITION OF TIN AND ZR(C,N) AT LOW SUBSTRATE TEMPERATURES USING A PULSED BIAS VOLTAGE

From the various physical vapour deposition processes, ion plating is known to produce dense hard coatings with an excellent adhesion to the substrates. By a combination of a d.c. and pulsed bias power supply with frequencies nu = 0-25 kHz and a separate adjustment of the various peak voltages, a flexible deposition method is found to achieve adherent coatings at relatively low substrate temperatures. The new technique is applied for the coating of planar plates and drilling tools of high speed steel with TiN and Zr(C, N) using a cathodic are plasma deposition process. The coatings are characterized performing scratch tests, Rockwell indentation tests and tool life tests. As a result the substrate temperature can be decreased to as low as DELTA-T = 100-150-degrees-C without loss of coating adhesion. Sometimes even better results are obtained at lower temperatures. A preliminary understanding of the experimental observations is presented.