Research On Preparation, Microstructure And Properties Of W-N Single Coatings、W-C-N Composite Coatings And Ti-Al-Si-N/W-N Multilayers Coatings

W-N single films, W-C-N composite films and Ti-Al-Si-N/W-N multilayer films wereprepared by reactive magnetron sputtering technique. Effects of nitrogen flow rate on W-Nsingle films’ microstructure and properties, Effects of power of C target and negative biasvoltage on W-C-N composite films, and Ti-Al-Si-N/W-N multilayer films’ microstructureand properties investigated. The main conclusions in this work are summarized as follows:The studies on the W-N single films indicated that the deposition rate decreasedsignificantly with the increase of N2flow rate. The α-W, β-W, β-W2N and δ-W-N phasesappeared at different values of nitrogen flow rate. The mean grain size of W-N single filmsdecreased with the increase of N2flow rate. The hardness and elastic modulus first increasedand then decreased with the increase of nitrogen flow rate. The hardness reached maximumvalue at10sccm of nitrogen flow rate. W-N films had a good interfacial adhesion (criticalforce L_c2>9N) and good wear resistance. With the increase of nitrogen flow rate, thefriction coefficient and wear rate of the films decreased, respectively, with the minimumvalue of0.32and6×10^-6mm³·N^-1m^-1. The main wear mechanisms for W-N films were theabrasive process and delamiation. Oxidation wear was also the main wear mechanism forW-N films with20sccm of nitrogen flow rate.The studies on the W-C-N composite films with different power of C target indicatedthat the β-WCN appeared when C joined W-N films, and the peak position was locatedbetween the β-WC and β-WN. With the increase of power of C target, the diffraction peaksshifted to a small angle. Because of solid solution, W-N lattice distortion appeared, and thehardness of W-C-N composite films improved. When C target power was120W, themaximum hardness and elastic modulus of W-C-N composite films were36.70GPa and409.16GPa, respectively. The friction and wear experiments at room temperature and hightemperature showed that the friction coefficient and wear rate of W-C-N composite filmsfirst decreased and then increased with the increase of C target power. The frictioncoefficient was higher than room temperature at high temperature. Abrasive wear was themain wear mechanism.The studies on the W-C-N composite films with different negative bias voltageindicated that only hexagonal α-WCN phase occurs as negative bias voltage was lower thanor equal to80V. However, as negative bias voltage further increased, hexagonal α-WCNphase changed to β-WCN phase. The hardness, elastic modulus and adhesive strength of W-C-N composite films first increased and then decreased with the increase of negative biasvoltage. The mechanical properties were optimized at120V of negative bias voltage. Theaddition of negative bias voltage resulted in improvement of surface quality and decreasedthe coefficient of friction and wear rate. As negative bias voltage increased to120V, thefilms get minimums wear rate and coefficient of friction around4.22×10^-6mm³·N^-1m^-1and0.27, respectively. Abrasive wear is the main wear mechanism. With the increase of negativebias voltage, the track of the worn surface was shallower. The wear mechanismaccompanied by oxidation wear at120V of negative bias voltage. When the negative biasvoltage was200V, the worn surface was relatively flat.The studies on the Ti-Al-Si-N/W-N multilayer films indicated that, the coatings takethe fcc structure with a （111） preferential orientation. The mean grain size decreased asincrease of modulation period. The hardness of Ti-Al-Si-N/W-N multilayers was about5.9GPa higher than that calculated from the rule of mixtures. The superhardness effect was notobserved. By means of adding W-N to the composition of Ti-Al-Si-N/W-Nnano-multilayered coatings, decreased the coefficient of friction of Ti-Al-Si-N monolithicfilm at room temperature. W-O tribo-films formed in synergy to alumina、 titanium andenhanced the wear-resistant of Ti-Al-Si-N/W-N at900℃. The minimum friction coefficientof Ti-Al-Si-N/W-N was0.16at high temperature.