ADI披覆無電鍍鎳及CAD-TiN複合鍍膜之沖蝕與腐蝕行為研究

Study on Erodion and Corrosion Behaviors of ADI Coated EN and CAD-TiN Duplex Films

陳貽宗(Yi-Tsung Chen)

指導教授 ： 許正勳

大同大學/工程學院/材料工程學系所/碩士(2009年)

摘要

延性鑄鐵(Ductile iron, DI)經過沃斯回火熱處理後，即形成沃斯回火延性鑄鐵(Austempered ductile iron)，簡稱ADI。ADI具有高強度、耐磨耗及低成本等優點，在工業上已有許多應用與發展，唯因為其基地中有許多球狀石墨(Spheroidal graphite)的存在，表面會因為球墨剝落形成許多孔洞等缺點，加速材料表面性質之劣化。本研究分別利用無電鍍鎳(Electroless nickel, EN)及無電鍍鎳摻雜碳化矽(Electroless nickel-carborundum, EN-SiC)作為中介層，然後再沉積CAD-TiN作為外表層。對照球墨粒徑大小披覆不同厚度的中介層，然後進行各種表面性質之分析(如硬度、附著性、耐腐蝕性、耐沖蝕性等)，以了解球墨大小與中介層厚度相互關係對其表面性質之影響。結果顯示，(1) 隨著中介層厚度增加至球墨粒徑的一半時( ~ 25μm)，CAD-TiN鍍膜附著性可由HF4提升至HF1；(2) 耐蝕性方面，在3.5 wt% 的NaCl溶液中之抗腐蝕能力提升了近60倍，在20 Vol.% 硫酸溶液中之抗腐蝕能力提升了近6倍；(3) 在耐沖蝕性方面，利用0.13 Kg/cm2的沖蝕壓力進行正向(90˚)的沖蝕試驗，發現耐沖蝕能力提升了約2倍。

關鍵字

沃斯回火延性鑄鐵 ； 耐蝕性 ； 無電鍍鎳 ； 陰極電弧沉積 ； 附著性 ； 濕式沖蝕

並列摘要

Austempered ductile iron (ADI) made by austempering heat treatment has been widely applied in the industry because it has some dramatic advantages such as high strength, wear resistance, and low cost. However, a lot of hole-defects occurred at the ADI’s surface due to the phenomenon of the spheroidal graphite peeled off, resulting in the deterioration of surface property. In this study, thus, two interlayer types consisting of electroless nickel (EN) and electroless nickel doped carborundum (EN-SiC) were respectively used with the different thickness before the out-layer TiN coating by cathodic arc deposition (CAD) treatment. According to the average size of spheroidal graphite, the interlayer thickness was designed as 5, 15, and 25μm. Then the properties of these duplex coatings such as hardness, adhesion, corrosion resistance, and erosion resistance were all analyzed for exploring the effects of the various interlayer conditions on the surface properties of ADI. The experimental results showed that when the interlayer thickness is up to 25μm regardless of EN and EN-SiC, (1) adhesion of CAD-TiN coating was improved from HF4 to HF; (2) the EN-SiC coated ADI had the best corrosion resistance among all the coated and uncoated conditions after polarization tests in 3.5wt% NaCl solution( 7.95×10-8 VS. 806.76×10-8 ~ 10.07×10-8); (3) the erosion resistance of ADI has raised twice in the performance as compared to uncoated on after wetting erosion tests at an impingement angle of 90˚ and pressure of 0.13 Kg/cm2.

並列關鍵字

Electroless Nickel plating ； Cathodic arc deposition ； Adhesion resistance ； Corrosion resistance ； Wet-erosion resistance ； ADI

參考文獻

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