Al含量对TiAlN涂层结构及性能的影响

目的 系统研究Al含量对TiAlN涂层结构以及硬度、热稳定性、抗氧化性能和耐腐蚀性能的影响.方法 利用阴极弧蒸发技术,采用Ti、Ti50Al50、Ti40Al60和Ti33Al67靶材制备出4种Ti1–xAlxN涂层.分别利用能量色散X射线光谱仪(EDX)、X射线衍射仪(XRD)、扫描电镜(SEM)、纳米压痕仪、热重分...

Effect of Al Content on Microstructure and Properties of TiAlN Coatings

To investigate the effect of Al content on structure as well as mechanical properties,thermal stability,oxidation resistance and corrosion resistance of TiAlN coating completely,we deposited 4 Ti_1?xAl_xN coatings by cathodic arc evaporation on Ti,Ti₅₀Al₅₀,Ti₄₀Al₆₀ and Ti₃₃Al₆₇ targets.The composition,structure,mechanical properties,thermal stability,oxidation resistance and corrosion resistance of Ti_1?xAl_xN coatings were studied in detail by energy-dispersive X-ray spectrometer(EDX),X-ray diffraction,scanning electron microscopy(SEM)with,nanoindentation,thermal gravimetric analyzer(TGA)and electrochemical workstation.All Ti_1?xAl_xN coatings exhibit a face-centered cubic(fcc-)structure.With the increase of Al content,the hardness values of Ti_1?xAl_xN continue to increase from~26.4 GPa of TiN to~32.7 GPa of Ti_0.38Al_0.62N.We detected the wurtzite(w-)AlN phase in Ti_0.55Al_0.45N and Ti_0.44Al_0.56N after annealing at 1100℃,however,in Ti_0.38Al_0.62N decrease to 1000℃.During the annealing process,the Ti_0.55Al_0.45N and Ti_0.44Al_0.56N show the highest hardness of~32.8 GPa and~33.3 GPa after annealing at 900℃respectively,and Ti_0.38Al_0.62N exhibits the highest hardness of~36.2 GPa at 800℃.After oxidation at 800℃for 20 h,the TiN coating has been completely oxidized,while the oxide layer thicknesses of Ti_0.55Al_0.45N,Ti_0.44Al_0.56N and Ti_0.38Al_0.62N coatings were~3.5μm,~0.6μm and~0.6μm,respectively.In addition,the oxidation activation energies of Ti_0.55Al_0.45N,Ti_0.44Al_0.56N and Ti_0.38Al_0.62N in parabolic oxidation stage are 530.9 kJ/mol,370 kJ/mol and 375.9 kJ/mol,severally.The last,the polarization resistance of TiN,Ti_0.55Al_0.45N,Ti_0.44Al_0.56N and Ti_0.38Al_0.62N is 4.59×10⁴??cm²,1.97×10³??cm²,3.71×103??cm²and 4.42×10⁴??cm²,respectively.In summary,within x<0.62,the coating maintains a single-phase cubic structure.With the increase of Al content,the lattice constant and grain size are reduced,the hardness values of Ti_1?xAl_xN continue is increased,and thermal decomposition is promoted.Ti_0.44Al_0.56N coatings have the best oxidation resistance.In addition,the introduction of Al reduces the corrosion resistance of the TiN coating,but the corrosion resistance of Al-containing coatings increases with increasing Al content.