PROPERTIES OF TIN HARD COATINGS PREPARED BY UNBALANCED MAGNETRON SPUTTERING AND CATHODIC ARE DEPOSITION USING A UNIPOLAR AND BIPOLAR PULSEDBIAS VOLTAGE

TiN hard coatings have been prepared by unbalanced magnetron (UBM) spu ttering and cathodic are deposition using uni- and bipolar pulsed bias voltages. For UBM sputtering using a unipolar pulsed bias voltage the average substrate bulk temperature T-s was reduced to 220 degrees C w ithout considerable loss of microhardness and adhesion by variation of the pulse parameters. Determination of the average energy E(p) delive red to the growing film per deposited particle leads to values lower t han the critical transition energy (150 eV atom(-1)) between open poro us and dense coatings. Using a bipolar pulsed bias voltage T-s decreas ed with increasing duration t(on)(+) of the positive bias pulse. It wa s found that E(p) increased with increasing t(on)(+) up to values foun d for d.c. bias voltage. The coatings prepared using a bipolar pulsed bias voltage at low T-s are dense and in compressive stress with accep table microhardness and adhesion. First results of the investigation o f TiN coatings prepared by cathodic are deposition using unipolar puls ed bias are given.