不同鎂鋁含量熱浸鍍鋅產品在酸性環境下耐蝕性質影響之研究

Study of the effects of the magnesium and aluminum additions on the corrosion resistance of the hot-dip galvanized products under the acidic environment

莊智軒(Chih-Hsuan Chuang)

指導教授 ： 王惠森

共同指導教授 ： 陳厚光(Hou-Guang Chen)

義守大學/理工學院/材料科學與工程學系/碩士(2021年)

摘要

本研究以三種未經表面處理、不同鍍層厚度且不同鎂鋁含量之熱浸鍍鋅產品(包含有:GI(Zn)、ZAM(6.0 wt.%鋁-3.0 wt.%鎂-鋅)及SuperDyma(11.0 wt.%鋁-3.0 wt.%鎂-鋅))在酸性CASS溶液中，分別以噴霧、浸泡及電化學等方法進行腐蝕測試，測試後針對其鍍層表面進行顯微組織、腐蝕產物、耐蝕特性等進行比較分析，藉以完整了解上述三種熱浸鍍產品在CASS酸性溶液環境之腐蝕形成機構及腐蝕動力學。
本研究耐蝕性比較分析的手法包含有不考慮鍍層厚度的產品耐蝕性優劣及考慮鍍層厚度的鍍層耐蝕速率。每個分析手法又包含三個面向，其中面向A是指開始生成特定腐蝕產物的時間及定義產生第一點特定腐蝕產物平均消耗鍍層量(鍍層厚度(μm)/產生起始特定腐蝕產物天數(D))；面向B是產生特定腐蝕產物占比的時間及產生特定腐蝕產物占比每天鍍層平均消耗速率；面向C是綜合考慮面向A及面向B。
在不同腐蝕測試方法及三個面向分析結果顯示，無論是CASS噴霧測試或CASS浸泡測試，SuperDyma由於鍍層較厚因此在產品耐蝕性優劣表現較佳；而ZAM本身耐蝕性質優良，因此在鍍層耐蝕速率時表現較佳；而電化學測試為本研究三種測試方試中最為嚴苛，且測試完成時間較為短暫，因此所有產品在實驗結果中並無明顯之鑑別度。因此，熱浸鍍鋅產品不建議採CASS電解液進行電化學測試。

關鍵字

噴霧 ； 浸泡 ； 電化學

並列摘要

In the study, three hot-dip galvanized products (including GI (Zn)、ZAM (6.0 wt.%Al-3.0 wt.%Mg-Zn) and SuperDyma (11.0 wt.%Al-3.0 wt.%Mg-Zn)), with different coating thicknesses, different the magnesium and aluminum additions and without surface treatment, are corrosion tested by using Spary, Immersion, and Electrochemistry test methods under the acidic CASS solution. After the tests, the microstructure, corrosion products and corrosion resistance characteristics of the coating surface are analyzed and compared in order to understand the corrosion formation mechanism and corrosion kinetics under the acidic CASS solution.
In the study, methods for comparative analysis of the product corrosion resistance include: product corrosion resistance without considering coating thickness, and corrosion resistance considering the coating thickness. Each analysis method contains three observation aspects, “aspect A” refers to the time when the specific corrosion products initially form and average consumption of the coating amount when the initial point of the specific corrosion product forms(coating thickness (μm)/ time to form the initial specific corrosion product); “aspect B”is time to form the proportion of the specific corrosion product, and the average consumption rate of the coating when the proportion of the specific corrosion products is produced. “aspect C” is a comprehensive consideration of “aspect A” and “aspect B”.
Based on the above test methods and three aspects, the results show, regardless of CASS Spary test or CASS Immersion test, SuperDyma has good performance on the product corrosion resistance, due to its thicker coating; However, considering the corrosion rate of the coating , ZAM has better performance on the corrosion resistance; The electrochemical test using CASS electrolyte is the most severe approach for three products in this study. Although the test completion time is shorter, all the products have no obvious difference in their electrochemical test results. Therefore, the use of CASS electrolyte for electrochemical testing of hot-dip galvanized products is not recommended.

並列關鍵字

GI ； ZAM ； SuperDyma ； CASS ； Spary ； Immersion ； Electrochemistry

參考文獻

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