Research On Microstructure And Corrosion Resistance Of TiCN And TiN/TiCN Films

The TiCN films under different deposition pressure and the TiN/TiCN multilayer films under different modulation period were deposited by composite ion plating. Morphology, surface composition, phase structures, surface roughness, hardness, friction coefficient and corrosion resistance in 3.5%NaCl, lmol/L H2SO4,0.5mol/L NaOH solution of these films were analyzed. The results show that the quality of TiCN films are improved. With the deposition pressure increasing, indicating that the TiCN films has well-distributed surface composition. In addition, the hardness magnified, while the friction coefficient and wear extent decreased with the deposition pressure increasing. When the deposition pressure is 0.6Pa, the TiCN films has the best quality. Because (Ti,C)/N of the film is close to 1:1 along with the hardness 2495.5HV, friction coefficient 0.386, and the wear extent 0.4mg. TiN/TiCN multilayer films can be beneficial to the surface quality. The friction coefficient and wear extent of those multilayer films are less than TiCN single layer. When molulation period is two, the surface quality of TiN/TiCN film is best. While the multilayer films of T=4 occured superhardness phenomenon. Because the film has 2921.3HV hardness and 0.296 friction coefficient. Besides, the wear extent is 0.1mg only. TiCN and TiN/TiCN films under different deposition parameters are mainly composed of TiCN, Ti2N, Ti with a (111) preferred orientation.In the solution of 3.5%NaCl, the corrosion resistance of TiCN films are improved with the deposition pressure increasing. The TiCN film deposited under 0.6Pa has the highest self corrosion potential,23.28mV, and the relative corrosion speed is 0.33 times of TiN film. TiN/TiCN multilayer films can be beneficial to the corrosion resistance in the 3.5%NaCl solution. Self corrosion current density number scale of different TiN/TiCN multilayer films are 10-7, less than TiCN single films. TiN/TiCN film of T=2 has the best corrosion resistance in 3.5%NaCl solution. TiCN single film's morphology shows serious surface roughening phenomenon, While TiN/TiCN multilayer film's morphology mainly shows narrow and deep holes with the soaking time extending. In the 1mol/L H2SO4 solution, compared to TiN film, the mainting passivity current density and the self corrosion current density of TiCN film deposited under 0.6Pa has an order of magnitude lower. Besides, the charge transfer resistance Rtis 70950 ?· cm2, being 35 times of TiN film. The corrosion resistance in lmol/L H2SO4 solution of different TiN/TiCN films is inferior to TiCN single film. Before the potentiodynamic polarization, TiN/TiCN film of T=2 has the higher Rt,7698?·cm2, but lower than TiCN single film. After the potentiodynamic polarization, the self-healing capability of TiN/TiCN mulilayer films is worse than TiCN single film. In the 0.5mol/LNaOH solution,before the polarization, the charge transfer resistance Rt of TiCN films decrease gradually with the deposition pressure increasing. After the polarization, the Rt of TiCN film of 0.6Pa is 2.552×105?·cm2, being 71 times of TiCN Rt before polarization. TiN/TiCN films deposited under different modulation period can be benefited to the corrosion resistance in the 0.5mol/LNaOH solution. TiCN single film's morphology shows well-distributed and shallow corrosion pits,while TiN/TiCN multilayer films'morphology shows heterogeneous and exposure corrosion pits in 0.5mol/LNaOH solution.