真空熱處理之氮化鋯薄膜氧化行為與防蝕性之探討

The Oxidation Behavior and Corrosion Resistance of ZrN Thin Films Annealed in Vacuum

郭昆麟

Advisor ： 黃嘉宏 ； 喻冀平

國立清華大學/原子科學院/工程與系統科學系/碩士(2015年)

https://doi.org/10.6843/NTHU.2015.00159

Abstracts

本研究的目的在於探討利用兩種鍍膜系統鍍氮化鋯薄膜於不鏽鋼上經真空熱處理後的氧化行為與防蝕性質。首先利用中空陰極放電離子覆膜系統及非平衡磁控濺鍍系統將氮化鋯薄膜鍍著於AISI 304 不鏽鋼基材上，之後將兩種試片同時於1000 °C、真空(4×10-6 Torr)的環境下，進行1到4小時的熱處理。由X光繞射圖顯示，試片即使經過長達4小時的熱處理，氮化鋯仍為主要相。此外，利用非平衡磁控濺鍍系統所鍍之氮化鋯薄膜其晶粒較利用中空陰極放電離子覆膜系統所鍍之薄膜大，使得兩者氧化後之薄膜表面晶粒大小也有相似結果，而晶粒大小也會影響熱處理後氧化相之生成。氧化後薄膜表面及膜與基材的界面附近分別形成外、內氧化層，推測是由於氧氣同時由薄膜表面及膜與基材介面的邊緣擴散進膜內而形成。動態極化掃描的結果顯示經氮化鋯覆膜之不鏽鋼氧化後展現極佳的抗蝕性，且試片腐蝕電流密度至多可下降至1000倍。經過500小時的鹽霧測試後，熱處理後之試片表面腐蝕面積均在6.7 %以下，且非平衡磁控濺鍍系統所鍍之薄膜抗蝕性更佳。另外，利用非平衡磁控濺鍍系統所鍍之氮化鋯薄膜經熱處理所得之全氧化試片，經過動態極化掃描與500小時鹽霧測試後展現極佳抗蝕性且薄膜也不會有脫落的現象，推測是經過熱處理後在膜與基材界面處產生的交互擴散層提高膜對基材的附著性。本研究結果顯示利用非平衡磁控濺鍍與中空陰極放電離子覆膜系統所鍍之氮化鋯薄膜均可藉由真空熱處理來成長氧化層，因此，非平衡磁控濺鍍可以取代中空陰極放電離子覆膜系統鍍製氮化鋯薄膜於不鏽鋼上來生產抗蝕性極佳之氧化層。

Keywords

氮化鋯 ； 氧化鋯 ； 熱處理 ； 防蝕性 ； 氧化行為

Parallel abstracts

The purpose of this study was to investigate the oxidation behavior and corrosion resistance of the vacuum annealed ZrN-coated stainless steel (SS) deposited by two deposition methods. ZrN thin films were deposited on AISI 304SS by hollow cathode discharge ion-plating (HCD-IP) and unbalanced magnetron sputtering (UBMS). Afterwards, the specimens were annealed at 1000°C in vacuum (4×10-6 Torr) for a duration ranging from 1 to 4 hr. The XRD results indicated that ZrN remained as the major phase in the oxidized thin films even after heat treating at 1000 °C for 4 hr in vacuum. Since the grain size of the as-deposited ZrN films by UBMS was larger than that by HCD-IP, the surface grain size of the oxidized film showed the similar results, which also affected the phase formation after vacuum annealing. The oxidized ZrN thin film on 304SS formed two oxide layers, the outer layer on the film surface and the inner layer nearby the film/substrate interface, which could be attributed to the simultaneous diffusion of oxygen from film surface and the edge of film/substrate interface, respectively. The results of potentiodynamic polarization scan showed that the corrosion resistance of the oxidized ZrN-coated SS was excellent and increased by about 1000 times relative to that of bare 304SS. The corrosion area after 500-hr salt spray test was less than 6.7 % for the oxidized ZrN-coated SS, and the oxidized ZrN films deposited by UBMS had better durability in salt spray test. The fully oxidized ZrN thin film deposited by UBMS showed great corrosion resistance and remained intact on 304SS substrate after potentiodynamic polarization scan and 500-hr salt spray test, which was associated with the enhanced adhesion by the interdiffusion layer from heat treatment. The results indicated that ZrN thin films deposited by both UBMS and HCD-IP could be used for the growth of oxidized layer by vacuum annealing. Therefore, UBMS could replace HCD-IP to deposit ZrN thin films on 304SS to produce an oxidized ZrN layer with excellent corrosion resistance.

Parallel keywords

zirconium nitride ； zirconium oxide ； heat treatment ； corrosion resistance ； oxidation behavior

References

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