篇名 | 預鍍鎳對低碳鋼熱浸鋁化層其顯微結構與組成相之影響 |
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卷期 | 25:3 |
並列篇名 | Effect of Nickel Pre-plating on the Microstructure and Phase Constitution of a Hotdipped Aluminide Coating on Mild Steels |
作者 | 鄭維仁 、 廖益樟 、 王朝正 |
頁次 | 161-168 |
關鍵字 | 預鍍鎳 、 熱浸 、 電子背向繞射 、 鋁化層 、 Pre-nickel plating 、 Hot-dipping 、 EBSD 、 Aluminide layer 、 EI |
出刊日期 | 201109 |
本研究採用預鍍鎳之低碳鋼熱浸於670°C之純鋁鋁湯。藉由掃描式電子顯微鏡(scanning electron microscope, SEM)、X-ray繞射(X-ray diffraction, XRD)、能量分散光譜儀
(energy dispersive X-ray spectroscopy, EDS)與電子背向繞射(electron backscatter diffraction,EBSD)技術,分析預鍍鎳對低碳鋼熱浸鋁化層其顯微結構與組成相之影響。研究結果顯示,低碳鋼上20μm 之預鍍鎳層在經過熱浸5秒後將溶解為12μm,並且在鎳層上方形成約5μm之連續Ni2Al3+NiAl3+(Fe,Ni)2Al9介金屬層與散布於純鋁塗層中的NiAl3相。當熱浸時間增加至60秒時,部分鎳鍍層被完全消耗完,使得Ni-Al 相開始轉變為FeAl3與(Fe,Ni)2Al9相。隨著熱浸時間持續增加,鋁化層將由外側少量的FeAl3與內側主要的Fe2Al5 相組成。對照沒有預鍍鎳之低碳鋼熱浸鋁化層可以發現,在經過長時間熱浸後,預鍍鎳之介金屬層其組成相及厚度與無預鍍鎳之介金屬層相同。
A nickel pre-plated mild steel was coated by hot-dipping in a molten bath containing pure Al at 670 °C. The effect of the pre-plated nickel layer on the microstructure and phase constitution of the aluminide layer was investigated using a combination of scanning electron microscope (SEM),
X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD). The results showed that the thickness of the nickel pre-plating layer was reduced from 20 μm to 12 μm due to dissolution after a hot-dipping of 5 seconds. Also, a continuous layer, composed of Ni2Al3 + NiAl3 + (Fe,Ni)2Al9, formed above the nickel plating layer, while a small amount of NiAl3 phase scattered in the aluminium topcoat. In the aluminide layer after a hot-dipping of 60 seconds, a portion of the nickel plating layer was consumed, leading to
phase transforms from Ni-Al to FeAl3 and (Fe,Ni)2Al9. As the dipping time increased, the aluminide layer was composed of FeAl3 in a minor amount and Fe2Al5 in a major amount. In comparison with the mild steel hot-dipped with aluminide but without nickel pre-plating, the phase
constitution and the thickness of the intermetallic layer with nickel pre-plating at a long dipping time were the same as those in the layer without nickel pre-plating.