ADI利用陰極電弧電漿沈積法披覆TiN/TiAlN之鍍膜特性及腐蝕行為研究

Study on Coating Characteristics and Corrosive Behaviors of ADI Deposited TiN/TiAlN by CAPD Method

賴奎良(Kuei-Laing Lai)

指導教授 ： 許正勳

大同大學/工程學院/材料工程學系所/碩士(2005年)

摘要

沃斯回火球墨鑄鐵(Austempered ductile iron, ADI) 因具備高強度、耐磨耗、耐疲勞、低成本等優點，已常被廣泛運用於機械零組件等領域；然而在諸多優勢下，ADI因受沃斯回火溫度(＜450℃)之限制，故無法進行傳統較高溫的表面熱處理以提升其性質。因此，本研究嘗試利用陰極電弧電漿沈積(Cathodic arc plasma deposition,CAPD)製程之低溫(≒200℃)表面改質方式，針對ADI材料表面進行披覆陶瓷硬膜(TiN及TiAlN)，然後分析ADI經表面披覆前後對於腐蝕性質之影響，並利用XRD、HRc、Hv、SEM等進行硬膜之特性分析。由實驗結果顯示：ADI表面經TiN及TiAlN兩種硬膜披覆之硬度(TiN-ADI之Hv≒1200~1400,TiAlN-ADI之Hv≒1700~1900)均較原ADI(Hv≒390~450)為高；靶電流增大時，披覆TiN之表面粗糙度與未披覆材變化不大，然而披覆TiAlN之表面粗糙度，則隨靶電流增加而增大，此結果與SEM影像觀察相互驗證；此外，利用SEM觀察HRc表面壓痕，發現TiN及TiAlN披覆在ADI表面上，除了球墨處之外，皆具有不錯之附著性。在腐蝕行為方面，經3.5wt%NaCl溶液之極化曲線試驗，結果顯示有TiN及TiAlN兩種硬膜披覆之試片其腐蝕電流皆較未披覆者為小;另經10 Vol.% HCl與10 Vol.%H2SO4溶液浸漬試驗後，也發現有TiN及TiAlN硬膜披覆者明顯地具有較小的腐蝕速率，因此意味著ADI經本實驗表面改質後，在鹽水、鹽酸及硫酸中均可提高其耐蝕性。

關鍵字

沃斯回火球墨鑄鐵、表面改質、陰極電弧沈積、TiN/TiAlN、耐蝕性

並列摘要

Austempered ductile iron (ADI) possesses high tensile strength, wear resistance, fatigue resistance and low cost, and it is widely applied on mechanical parts. In general, austempering temperature of ADI is in the range of Ms~450℃, thus, the traditional heat treatment at high temperature for case hardening is not available to treat ADI. This research used the method of cathodic arc plasma deposition (CAPD) to coat TiN/TiAlN on ADI substrate and explored the effect of the surface coatings on corrosion behaviors of ADI. Moreover, XRD, HRc and SEM were further utilized to analysis the various properties of the coating films. The results showed that the hardness of the coated ADI is higher than that of uncoated ADI. However, the surface of coated ADI specimens is rougher than that of uncoated ADI. The adhesion between film and ADI substrate is better than that between film and graphite substrate. After polarization curves test, it was found that the corrosion current of coated specimen is smaller than that of uncoated specimen. Moreover, in 10 Vol.％HCl and 10Vol.%H2SO4 solution , the coated specimens process the lower corrosion rate than uncoated specimen. Thus, it implied that ADI coated with TiN/TiAlN films can evidently raise the corrosion resistance in sea water,hydrochloric acid and sulphuric acid.

並列關鍵字

Austempered ductile iron ； Cathordic arc deposition ； Corrosion resist ； Surface modification ； TiN/TiAlN

參考文獻

6.R.B Gundlach and J.F. Janowak, First International Conference on Austempered Ductile Iron Castings, pp.1–12, 1983

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