AISI D2 工具鋼經離子氮化處理對TRD生成之碳化鉻披覆層的耐磨耗性改善研究

Wear Resistance Improvement of AISI D2 Tool Steel by Post Treatment of Plasma Nitriding on Chromium Carbide Coating Prepared by TRD

魏振益(Chen-Yi Wei)

指導教授 ： 陳繁雄

大同大學/工程學院/材料工程學系所/博士(2005年)

摘要

改良式熱反應沉積擴散是於低壓流體床內實施。本研究是採非接觸法，活化劑周期地加入合金粉末中用以產生提供處理所需之氣氛。處理之冷作工具鋼AISI D2試片懸掛於流體床上方，壓力介於6.7×102 Pa ~ 5.3×104 Pa，可大量減少流體床化氣體，亦大幅擴大處理空間。反應動力學之研究亦由實驗中證明活化劑添加可有效降低活化能。當藉由雙重處理(以熱反應沉積擴散形成碳化物再經電漿滲氮)形成之氮化鉻層更提高了只經熱反應沉積擴散形成之碳化物層之耐磨耗性。

關鍵字

碳化鉻，氮化鉻，熱反應沉積/擴散，電漿滲氮，流體床

並列摘要

A modified TRD (Thermoreactive Deposition / Diffusion) has been investigated in a low pressure fluidized bed furnace in this study. The steel specimens AISI D2 were positioned above the surface of the alloying powder. The activator was periodically introduced into the alloying powder to provide the working atmosphere for the required process. Since the pressure of the retort was maintained between 6.7×102 Pa and 5.3×104 Pa, the consumption of fluidized gas (argon) was reduced significantly. A modified TRD also significantly increased the working space of the treating zone. Furthermore, the kinetics of reaction K = K0 exp(-Q/RT) was empirically determined in this study. It is shown that the activator, NH4Cl, can effectively lower the activation energy Q, as well as enhance the formation rate of the carbide layer.
The chromium nitride obtained from TRD followed by plasma nitriding (dual treatment) provides more resistant than that of the solely TRD treated one.

並列關鍵字

Chromium carbide ； Chromium Nitride ； Fluidized bed technique ； Plasma nitriding ； Thermoreactive deposition/diffusion

參考文獻

[1] A.R. Castle and D.R. Gabe, Structure characteristics of M23C6 formed in chromised coatings on 11%Cr steels, Materials Science and Technology, 16 (2000)p.1057-1066.

[2] R.C.Jongbloed, Chromizing, Materials Science Forum 163-165 (1994) p.611-618.

[4] Fan-Shiong Chen, Pee-Yew Lee, Ming-Chyi Yeh, Thermal reactive deposition coating of chromium carbide on die steel in a fluidized bed furnace, Material Chemistry Physics, 53 (1998) p.19-27.

[5] T. Arai, H. Fujita, Y. Sugimoto, and Y. Ohta, Diffusion carbide coatings formed in molten borax systems, J. Materials Engineering, 9,2(1987) p.183-189.

[7] F.J.Perez, M.P.Hierro, F.Pedraza, C.Gomez, M.C.Carpintero, Aluminizing and chromizing bed treatment by CVD in a fluidized bed reactor on austenitic stainless steels, Surface and Coating Technology 120-121 (1999) p.151-157.