甲烷添加量對不銹鋼電漿滲氮碳化之影響

Effect of CH4 Addition on the Plasma Nitrocarburized Layer of Stainless Steel

蘇洋右(Yang-Yu Su)

指導教授 ： 邱六合

大同大學/工程學院/材料工程學系所/碩士(2008年)

摘要

本研究採四種不鏽鋼進行低溫電漿軟氮化處理，四種不鏽鋼之結構分別為沃斯田體系AISI 316、麻田散體系AISI 410、肥粒體系AISI430與γ+α之雙相SAF 2205組合。在電漿處理製程參數選用不同氮氫比並加入不同比例的甲烷氣體，評估不同結構不鏽鋼經電漿軟氮化處理後不同滲層之電阻率及硬度。
本實驗著重以不同氣體比例進行420℃低溫電漿軟氮化，並採用活動網罩方式進行。沃斯田體系不鏽鋼採用低溫電漿處理時，形成一未有任何析出物，為氮原子及碳原子過飽和固溶體的滲層，稱之為S phase。由於沒有鉻化物析出，基底仍保留原材之鉻含量，除不會降低原來之有耐腐蝕性外，並可降低其電阻率。麻田散體型不鏽鋼及肥粒體系不鏽鋼主要形成γ’-Fe4N, ε-Fe2-3N之氮化層，此層雖有較高之表面硬度，但電阻率則有昇高之趨勢。雙相不鏽鋼之滲層為則S phase 及γ’-Fe4N, ε-Fe2-3N之化合物，其電阻率則略高於原材。

關鍵字

甲烷 ； 活性網罩 ； 電漿軟氮化 ； 不鏽鋼 ； 電阻率

並列摘要

Four kinds stainless steel designated AISI 316, 410, 430 and SAF 2205 were plasma nitrocarburized for investigation of their electrical resistance, microstructure and hardness distribution of the hardened layers.
Plasma nitrocarburizing at low temperature of 420°C with an active screen applied in the process produced a single phase nitrided layer of nitrogen and carbon expanded austenite (S phase) on the specimen surface, which considerably improved the resistivity property of AISI 316 austenitic stainless steel. According to the phase, γ’-Fe4N and ε-Fe2-3N, dominated in the nitcarburized layer, the resistivities of plasma nitrocarburized 410 and 430 specimens are higher than those of the substrate.

並列關鍵字

Active screen ； S phase ； Stainless steel ； Plasma nitrocarburizing ； resistivity

參考文獻

[1] C.X. Li and T. Bell, “Wear Properties of Active Surface Plasma Nitrided 316 Austenitic Stainless Steel,” Wear Vol.256, p.p.308-314, 2003

[2] C.X. Li and T. Bell, “Corrosion Properties of Active Screen Plasma Nitrided 316 Austenitic Stainless Steel,” Corrosion Science Vol. 46, p.p.1527-1547, 2004

[5] Wang Liang, “Surface Modification of AISI 304 Austenitic Stainless Steel by Plasma Nitriding,” Applied Surface Science, Vol.211, p.p.308-314, 2003

[6] Z. Cheng, C.X. Li, H Dong and T. Bell, Low temperature plasma nirtocarburising of AISI 316 austenitic stainless steel, Surface and Coatings Technology ,Vol.191,p.195-200. 2005

[7] ASM Metal Handbook, Heat Treating, Plasma Nitriding, vol.4, p.p.422, 2000