活化網罩電漿滲氮對雙相不銹鋼腐蝕及磨耗性質之影響

Effect of Active Screen Plasma Nitriding on the Corrosion and Wear Properties of Duplex Stainless Steel

張記銨(Chi-An Chang)

指導教授 ： 邱六合

大同大學/工程學院/材料工程學系所/碩士(2007年)

摘要

本研究目的在於雙相不銹鋼 (UNS S31803) 經不同溫度及時間電漿滲氮後，進行耐腐蝕性量測及磨耗試驗，希望可以獲得經電漿滲氮後有提升表面硬度增加耐磨耗性，以及避免雙相不銹鋼經電漿滲氮後的耐腐蝕性質下降。由實驗結果得知，雙相不銹鋼在400℃至450℃下電漿滲氮皆會有S-phase的產生，420℃下施以電漿滲氮10至20小時，可提升耐腐蝕性質亦有改善，當時間漸增加至25小時會造成其耐腐蝕性質的降低。而電漿滲氮的溫度在435℃以上因開始有較多CrN的析出物，造成其耐腐蝕性質明顯的下降。而經過電漿400至450℃滲氮後的DSS試片，氮化層的硬度皆900HV以上，在可明顯提升耐磨耗性。UNS S31803雙相不銹鋼之活化網罩電漿氮化處理較佳的製程參數為處理溫度在420℃以下而時間則需控制在20小時以下。

關鍵字

活化網罩 ； 電漿滲氮 ； 腐蝕 ； 雙相不銹鋼

並列摘要

Active screen plasma nitriding (ASPN) on the corrosion properties of UNS S31803 duplex stainless steel with different temperature and times has been studied. The surface hardness of ASPN DSS specimen was raised to 1000~1200HK. From the experimental results, the S-phase (γN) and αN phase were observed in the surface of ASPN DSS specimens conducted under 400 to 450℃, and increasing corrosion resistance at 420℃ with 10-20 hours after plasma nitriding. When working time increase to 25 hours will lose the property of corrosion resistance, and working temperature above 435℃ will also lose the property of corrosion resistance due to chromium nitride formation. The hardness of nitrided layer reach to 900HV above and increasing wear resistance obviously after plasma nitriding. Working temperature and time below 420℃ and 20 hours are the optimum treatment condition of duplex stainless steel by active screen plasma nitriding.

並列關鍵字

Active screen ； Plasma nitriding ； Corrosion ； Duplex stainlee steel

參考文獻

[2] R.A. Walker, Duplex and High Alloy Stainless Steels-corrosion Resistance and Weldbility, Material Science and Technology, (1988), Vol.4, pp.78-84.

[3] P. Merino, X.R. Novoa, G. Potro and L. Espada, Intergranular Corrosion Susceptibility of Austenic-ferritic Duplex Stainless Steels:Appication of Potentiokinetic Reactivation Tests, Materials Science and Technology, (1993), Vol.9, pp.168-171.

[4] L.F. Garfias-Mesias, J.M. Sykes, Matastable Pitting in 25 Cr Duplex Stainelss Steel, Corrosion Science, (1991), Vol.41, pp.959-987.

[5] J.K.L. Lai, K.W. Wong and D.J. Li, Effect of Solution Treatment on the Transformation Behaviour of Cold-rolled Duplex Stainless Steels, Materials Science and Engineering, A203 (1995), pp.356-364.

[7] M.E. Wilms, V.J. Gadgil, J.M. Krougman and F.P. Ijsseling, The effect of σ-phase precipitation at 800℃ on the corrosion resistance in sea water of a high alloyed duplex stainless steel, Corrosion Science, Vol.36, No.5, pp.871-881.