| Summary: | 碩士 === 國立清華大學 === 工程與系統科學系 === 94 === Nano-crystalline Ti(N,O) films were successfully deposited on AISI 304 stainless steel substrates using unbalanced magnetron sputtering (UBM) system with addition of oxygen and nitrogen at 350℃. The effect of oxygen flow rate was investigated on the composition, microstructure and properties of Ti(N,O) thin films. From X-ray photoelectron spectroscopy (XPS) and XRD results, phase transformation of TiN phase displaced by Ti3O5 phase was observed. The diffraction patterns of XRD revealed that the texture evaluation from random distribution to (111) preferred orientation and then to (200) texture structure occurred at the oxygen content ranging from 4 to 5 at % and 5 to 23 at %. It was resulted from hindering of Ti adatoms by oxygen atoms stuck on (200) plane of TiN phase. The measured film hardness could be influenced by adhesion between the substrate and the films. Residual stress does not have clear trend with the oxygen content of films due to the possible effect of amorphous phase in the films. The results of potentiodynamic polarization test in 0.5M H2SO4 + 0.05M KSCN solution showed that Ti3O5 phase would affect the corrosion behavior. With higher packing density, Ti(N,O) thin films showed better corrosion resistance in H2SO4 solution. The results showed that the film coloration changes from warmer golden to vivid green and then to pink because N/Ti ratio influenced the free d electrons from Ti atoms and the number of free d electrons available for conductivity changes.
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