合金元素對熱壓燒結鋁–矽合金之磨耗腐蝕行為影響研究

Effect of Alloying Elements on the Wear-Corrosion Behavior of Al-Si Alloys Formed by Hot Pressing

以熱壓燒結製程製作含不同Pb(0-10 wt %)、Cu (3 wt%)之Al-Si（20 wt%）複合材料，並施以熱處理後，利用微結構分析、硬度與緻密度量測、磨耗、腐蝕、與磨耗腐蝕試驗，來評估Pb、Cu元素對Al-20Si合金在3.5wt%氯化鈉（NaCl）水溶液中（pH=6.7）磨耗腐蝕行為之影響。結果顯示經熱壓製成之Al-Si-Pb-Cu複合材料，其緻密度約為理論密度的99%。添加Cu於Al-Si與Al-Si-Pb合金中可提升其硬度，其中Al-Si-Pb-Cu合金之硬度提升比例隨Pb含量增加而上升。於乾磨耗試驗中，合金磨耗量隨著Pb含量的增加而降低，而添加Cu於Al-Si合金中可強化基地，進一步提升其抗磨耗性質。而於腐蝕實驗中，添加Pb、Cu元素均會使合金之腐蝕電流上升，然而，當合金經熱處理後，除了Al-Si合金腐蝕電流升高外，其餘合金之腐蝕電流皆下降，並且腐蝕電位也顯得較為鈍性。此外，添加Pb則可促進合金的鈍化。Al-Si合金具有優良之磨耗腐蝕性質，磨耗量隨外加電位往陽極增加而降低，而添加Pb和Cu皆可提升Al-Si合金之耐磨耗腐蝕性質，並且含Pb合金，由於具有良好的鈍化行為，當外加電位達鈍化區時，腐蝕電流與磨耗量皆明顯下降。

The wear-corrosion behavior of Al-20Si-XPb-YCu (X=0-10 wt %,Y=0-3 wt %) alloys, fabricated by a hot pressing technique and subsequent heat treatments, was evaluated by a block-onring tribotest. The evaluation examined the effects of applied potentials and environments which included dry air and 3.5wt% NaCl solution. The corrosion behavior was determined by Tafel polarization tests. The results showed that the additions of both lead and copper improved the wear resistance but led to higher corrosion rates. Heat treatments had a beneficial effect on the corrosion resistance of most alloys with the exception of Al-Si alloy. Al-Si alloys had excellent wear corrosion resistance, which increases with the increasing applied potentials. Additions of lead and copper further improved wear corrosion resistance. In addition, the passivity of lead containing Al-Si alloys increased substantially, which was responsible for the apparent reduction of both wear rate and corrosion current in the passive potential region during the wear-corrosion test.