鎳鉻鉬合金鋼表面鐵鋁合金硬化處理之研究

本研究利用中碳鎳鉻鉬合金鋼作為底材，在400°C∼700°C的低溫，進行2∼24小時的滲鋁還原反應，藉由化學反應與固態擴散的方式，針對鋼材表面進行改質，在鋼材表面生成高硬度、耐腐蝕及高溫抗氧化性佳之鐵鋁基合金，提昇鋼鐵表面機械與抗腐蝕性質。報告中探討滲鋁溫度及滲鋁時間等製程參數，對於擴散層相成分與厚度之影響，並評估其表面機械性質與耐腐蝕性改善之情形，以得到最佳化的製程控制參數與表面性質，期能控制硬化層厚度與機械性質，降低硬化處理之成本，應用於高強韌性能需求之場合。實驗顯示，本研究最低處理溫度為400°C，成功的將滲鋁處理溫度降低至鋼鐵的退火溫度以下，使母材處理後仍擁有良好的韌性與強度。滲鋁溫度及滲鋁時間影響了擴散層厚度、相成分與機械性質，本研究之生成相的厚度介於15∼100um，所得之活化能為15.23 KJ�mole，表面的鐵鋁鍍膜可以生成兩種不同相的擴散層，經由EDS與XRD分析，最外層之生成相為鐵鋁之介金屬化合物－Fe2Al5，中間層則為Fe3Al結構之合金層，其硬度可以達到Hv600以上，且有更佳之耐磨耗性。

關鍵字

鐵鋁基合金；滲鋁；粉體滲透法；表面硬化；固態擴散

並列摘要

Low-temperature formed Fe-/Al intermetallic compound by aluminizing on the surface of a Ni-Cr-Mo containing medium carbon steel was investigated. The processing temperatures were ranged between 400°C and 700°C. The diffusion time was varied from 2 to 24 hours. The structures, phases, and mechanical properties of the coating layers were studied. The thickness of coating layers were in the range of 15um~100um. The activation energy for formation of the coating layers was estimated 15.23 KJ/mole. The coating layers consist of two different phases. The Fe2Al5 phase was formed on the surface layer and the solid solution with Fe3Al structure was formed at the interface between surface Fe2Al5 layer and the substrate. The surface hardness is higher than Hv600 while keeping the substrate hardness at relatively high level.

並列關鍵字

Fe-Al intermetallic compounds ； aluminization ； pack cementation ； case hardening ； solid phase diffusion

參考文獻

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鎳鉻鉬合金鋼表面鐵鋁合金硬化處理之研究

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