The Fabrication And Properties Of Titanium Nitride And Silicon Nitride Films

Titanium nitride, Ti/TiN multilayer films and silicon nitride with different composition, microstructure, mechanical and corrosion resistance properties were synthesized by unbalanced magnetron sputtering. The films thickness was tested by AMBIOS Xp-2 profile meter. The microstructure and composition were characterized with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy and scanning electron microscopy (SEM). The mechanical properties, such as microhardness, wear resistance and the adhesion strength between films and substrate, were characterized with HXD～1000 microhardness meter, CSEM pin-on-disk wear test apparatus and WS-97 scratch tester. The corrosion resistance of films was characterized with different method because of the different application of the films.The effect of the N₂ and Ar partial pressure ratio (P_N2/P_Ar and bias voltage on Ti-N film microstructure and properties were studied; the effect of the periods on the Ti/TiN multilayer films were analyzed; the effect of the N₂ and Ar partial pressure ratio (P_N2/P_Ar) on Si-N film microstructure and properties were studied.The titanium nitride films with different microstructure and properties were synthesized at different N₂ and Ar partial pressure ratio (P_N2/P_Ar) and bias voltage by unbalanced magnetron sputtering. The results showed that Ti-N films deposited by unbalance magnetron sputtering were compact. The Ti₂N phases were found in the Ti-N films, and Ti₂N dexreased with N₂ and Ar partial pressure ratio (P_N2/P_Ar) increasing. The Ti₂N existed in the films can significantly improve the microhardness and wear resistance of the Ti-N films.Titanium nitride films have been widely applied in mechanical engineering due to their high hardness, excellent wear resistance and good chemical stability. However, monolayer films of TiN deposition by PVD techniques, generally have a columnar microstructure, and these columnar grain boundaries always result in failure of TiN films.It has been reported that the multilayered structure can be used to overcome this problem since the interfaces between the layers can periodically interrupt the growth of columnar grain. The properties of the multilayer films were mostly influenced by the periods. In this paper Ti/TiN multilayer films with periods from 100nm to 350nm were synthesized by unbalanced magnetron sputtering. The SEM images demonstrate that the Ti/TiN multilayer films with different periods were produced at an excellent periodicity. The crystal grain of the Ti/TiN multilayer films became more compact as the decrease of the period. The micro-hardness and wear resistance of the multilayer films increased with the periods decreasing. The potentiodynamic polarization scans in 3% NaCl solution showed that the Ti/TiN multilayer films can be used to significantly improve the corrosive resistance of the stainless steel.The thermal humid exposure showed that the corrosion resistance of the multilayer films decreased with the period decreasing.It is indicated that all the SiN_x films synthesized at different N₂ and Ar partial pressure ratio (P_N2/P_Ar) by unbalanced magnetron sputtering. The results showed that the absorption band observed at 870～930cm^-1 corresponds to Si-N /Si-O was shifted to left because of having more Si-N bonds with increasing the N₂ and Ar partial pressure ratio (P_N2/P_Ar). Besides, the additional absorption bands correspond to Si-N observed at 475～490cm^-1 became obvious when the P_N2/P_Ar increasing. Micro-hardness test and wear resistance test results showed that the hardness and wear resistance increased when the P_N2/P_Ar increasing, then decreased slightly when the P_N2/P_Ar increasing. The adhesion strength between films and substrate was well, and the brittleness of the Si-N films increased when the P_N2/P_Ar increasing.