| Nanocomposite coatings had drawn more and more attention for excellent properties and thermal stability. But the coatings’properties were varied because of it’s inevitably that oxygen impurities exited in the coatings, the universal application of nanocomposite coatings in high-speed cutting were limited. And the papers reported the influence of oxygen content to coatings’structure and properties were few. On the other hand, the energy of deposited grains effected coatings’performance remarkable. So it’s effective to changed bias voltage for controlling the energy during deposited coating.In this study, CrAlSiON coatings were deposited by multi-arc ion plating technology on cemented carbide substrate with different ratios of oxygen to nitrogen. The technology of SEM, XRD, nano-indentation and scratch test were used to investigate coatings’structure, properties and tribological behavior, and the thermal stability was studied by vacuum annealing. Based on those research, CrAlSiON coatings were deposited with different bias voltage to analysis the influence of deposited grains’energy to coatings’structure, properties and thermal stability.1. The ratio of O2/O2+N2 was increased from 0 to 18% to deposited CrAlSiON coatings, and oxygen content was changed from 0 to 62.19at.%. The main phases were CrN and Al2O3 in as-deposited coatings. Compared with the coatings with high oxygen content, surface defect of the coatings with low oxygen content was fewer and roughness was smaller than that of the coatings with high oxygen content. With oxygen content increasing, coatings’hardness decreased. When oxygen content was 48.4at.%, hardness decreased to 21.43GPa, and then with oxygen content keep increasing, coatings’ hardness maintained this value. The variation of elastic modulus and H3/E*2 were similarly to hardness. The adherent strength of the coatings with high oxygen content were poorer than that of coatings with low oxygen content. The main styles of high-temperature tribological behavior were abrasive wear and adhesive wear, all of those coatings were wear through. With vacuum annealing temperature increasing, hexagonal Cr2N phase was appeared due to the decomposition of CrN phase, which lead the coatings’ hardness, elastic modulus, H3/E*2 and adherent strength decrease.2. To deposite the CrAlSiON coatings with low oxygen content, bias voltage was increased from -60V to -200V, and the O2/O2+N2 ratio was 2%, oxygen content in coatings was 22at.% to 25at.%. The oxygen content in the coatings deposited by high bias voltage were more than that in the coatings deposited by low bias voltage. The surface defect of the coatings deposited by low bias voltage was fewer and roughness was smaller than that of the coatings deposited by high bias voltage. With bias voltage increasing, coatings’hardness were increased first, then decreased, finally remained unchanged, the coating deposited by the bias voltage of -80V obtained the biggest hardness of 33.6GPa. The variation of elastic modulus and H3/E*2 were similarly to hardness. The adherent strength of coatings increased slowly with bias voltage increasing, the critical load of scratch test changed from 63.58N to 74.36N. During room-temperature tribological test, the wear rate of the coatings deposited by low bias voltage was smaller than that of the coatings deposited by high bias voltage. The coatings deposited by the bias voltage of-80V obtained the smallest wear rate. During high-temperature tribological test, the wear rate of the coatings deposited by the bias voltage of-80V and-100V were smaller than that of the coatings deposited by higher bias voltage. With vacuum annealing temperature increasing, hexagonal O2N phase was appeared due to the decomposition of CrN phase, which result in the decrease of the coatings’hardness, elastic modulus, H3/E*2 and adherent strength.3. To deposite the CrAlSiON coatings with high oxygen content, bias voltage was increased from-60V to-200V and the O2/O2+N2 ratio was 12%. oxygen content in coatings maintained the value of 60at.%, which indicated oxygen content was sensitively to bias voltage. The main phases of coatings were CrN and Al2O3 phase, and the peak intensity decreased with bias voltage increasing. Coatings’hardness, elastic modulus, H3/E*2 and adherent strength increased with bias voltage increasing. During room-temperature tribological test, the coatings deposited by low bias voltage were wear through, but the wear resistance of the coatings deposited by high bias voltage were good. With vacuum annealing temperature increasing, the coatings’hardness, elastic modulus, H3/E*2 decreased and adherent strength increased. |
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