Properties of TiN hard coatings prepared by unbalanced magnetron sputtering and cathodic arc deposition using a uni- and bipolar pulsed bias voltage
TiN hard coatings have been prepared by unbalanced magnetron (UBM) sputtering and cathodic arc deposition using uni- and bipolar pulsed bias voltages. For UBM sputtering using a unipolar pulsed bias voltage the average substrate bulk temperature Ts was reduced to 220 °C without considerable loss of microhardness and adhesion by variation of the pulse parameters. Determination of the average energy Ep delivered to the growing film per deposited particle leads to values lower than the critical transition energy (150 eV atom−1) between open porous and dense coatings. Using a bipolar pulsed bias voltage Ts decreased with increasing duration ton+ of the positive bias pulse. It was found that Ep increased with increasing ton+ up to values found for d.c. bias voltage. The coatings prepared using a bipolar pulsed bias voltage at low Ts are dense and in compressive stress with acceptable microhardness and adhesion. First results of the investigation of TiN coatings prepared by cathodic arc deposition using unipolar pulsed bias are given.