6061鋁基複合材料在NaCl溶液磨耗腐蝕之研究

The Study of Corrosion Wear of 6061 Al/Al2O3 Metal Matrix Composites in NaCl Solution

本研究最主要目的在於探討氯離子對於Al/Al2O3複合材料磨耗行為之影響。本實驗乃利用塊環式（block-on-ring type）之磨耗試驗機於3.5 wt% NaCl溶液及去離子水環境下，針對垂直負荷3.95N及90rev/min轉速之Al/Al2O3試片進行磨耗試驗。而Al/Al2O3試片有下面各種不同熱處理：(1)underaged（530℃；2hrs），(2)T6（aged at 160℃；18hrs）(3)overaged（aged at 160℃；120hrs）。由實驗之結果可知，上述二者測試環境重量損失都非常小，但在3.5wt NaCl 溶液之損失量較去離子水為大。若以不同熱度條件處理在3.5wt NaCl溶液下之磨耗腐蝕速率比較為：underaged > overaged > T6處理。可見Al/Al2O3複合材料磨耗腐蝕機構，可視為A/Al2O3在底材（Al）中剝落，因局部缺陷而造成腐蝕粒子堆積所致。

The main objective of this work is to study the effect of chloride ion on the wear behaviour of Al/A12O3 composites. Corrosion-wear test of Al alloy 6061/Al2O3 meatal matrix composites (MMCs) has been performed in a 3.5% NaCl solution at room temperature. The specimens were tested with a modified block-on-disc type machine, with a normal loading of 3.95 newtons and rotation speed of 90 rev/min. Three sets of specimens with different heat treatments were prepared. The heat treatments were：as-solutionized (530℃ for 2 hours), T6 (aged at 160℃ for 18hours), and overaged (aged at 160℃ for 120 hours). After different periods of wearing test, the weight loss of each specimens was measured. The weight loss caused by the action of corrosion alone was very small. The weight loss of all specimens tested in the 3.5%solution was greater than that in the distilled water. The order of increasing wear resistance in the distilled water was：as-solutionized, overaged, and T6 condition. However, in the 3.5% NaCl solution the overaged specimen was found to suffer severe corroston wear damage, and the one after T6 treatment was still the best amongst the three. It was found that the Al2O3/Al interface was corroded in the 3.5% NaCl solution, this caused the pull out of Al2O3 and obviously deterlorated the wear resistance of the MMCs。