| Magnesium and its alloys have been paid attention to and used in many fields suchas aerospace industry, microelectronics, automotive industry because of their largereserves and excellent properties in the last few years. However, magnesium and itsalloys are too sensitive to corrosion that limits their applications. To improve theircorrosion resistance is the most important issue in magnesium industry, there are twomain approaches to improve the corrosion resistance of which one is improving thealloy technics and another is to modify the surface property of magnesium alloy.Magnetron sputtering was deemed to be one of the best methods to prepare the exteriorcoating because of the high film quality, simple technics and environment-friendlyfeature.In this study, both double-target magnetron react sputtering and TiNCcompound-target depositing technology were used to prepare titanium carbonitride filmon the substrate of AZ31magnesium alloy. Field emission scanning electron microscope,X-ray diffraction, X-ray photoelectron spectroscopy instrument and profilometer wereapplied to investigate the surface morphology, microstructure, chemical composition,film thickness and surface roughness of the film, respectively. The corrosion resistanceof the film was studied by electrochemical test, and the influence of the preparationparameters to the film quality was researched. The adhesion between film and substratewas evaluated by cross cut tape test.The research results show that the films prepared by two manners both areamorphous structure and the adhesions of coating to the substrate are all classified to5Bgrade. The double-target react prepared film has the best corrosion resistance when theC target sputtering power is50W, the Ti target sputtering power is50W, the N2flow rateis20sccm and the sputtering time is4.5h. The corrosion current density(1.664×10-6A/cm2) was reduced by an order of magnitude compare to the magnesiumalloy substrate (1.785×10-5A/cm2). The TiNC film prepared by compound target couldalso increase the corrosion resistance of the substrate, the corrosion current density(4.307×10-6A/cm2) was reduced by nearly an order of magnitude compare to thesubstrate(1.785×10-5A/cm2).The titanium carbonitride films prepared by different ways are vary in surfacemorphology and chemical compounds. The surface of the titanium carbonitride film prepared by double-target reaction is compact and has no obvious defects, but thereexist a little defect on the surface of the titanium carbonitride film prepared bycompound target. The titanium carbonitride film prepared by double-target reaction hasbetter corrosion resistance, the technics, however, is complicated and the cost is ratherhigh. The titanium carbonitride film prepared by compound target has a simple technicsand lower cost but the preparation technology needs optimized to improve the corrosionresistance. These two kinds of film could improve the hardness of magnesium substrate,which expands the range of titanium carbonitride film’s application on the magnesiumsubstrate. |
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