台灣地區大氣腐蝕季節性之比較

Comparison of Seasonal Atmospheric Corrosion in Taiwan

台灣為一海島四面環海高溫、高溼與高鹽份的環境，加上空氣污染的結果，腐蝕環境嚴重。本文針對台灣大氣腐蝕環境與碳鋼、鋅、銅、鋁四種金屬之腐蝕速率進行夏季季風期與東北季風期之比較。結果顯示，東北季風期金屬之腐蝕速率較夏季季風期為高，即東北季風帶來的濕氣與空氣中氯鹽、SO2含量，增加了各金屬的腐蝕速率。此外，空氣中氯鹽含量輸送到內陸的分佈，受到風速、風向、局部地形的影響，距海岸線愈遠，氯鹽沉積速率愈小；距離海岸約3000 m左右時，氯鹽的沉積速率明顯降低且趨於一定值。

Taiwan is an island with the tropical and subtropical climates of high humidity and high chloride contents. The cost incurred by atmospheric corrosion and corrosion prevention is considerable because of the climates, industrial development, and traffic pollution. In the present study, comparisons of seasonal variations in atmospheric corrosion and in the corrosion of Fe, Zn, Cu, and Al were made. Particular attention was focused upon the periods of southwestern monsoon and northeastern trade winds. It was found that corrosion rates of the metals were comparatively higher in the season of northeastern trade winds due to higher levels of humidity, chlorides, and SO2. In addition, the distribution of chlorides in air was influenced by wind velocity, wind direction, as well as screen effects of topography. The chloride deposition rate decreased with increasing distance to the coastal line. No significant changes in chloride deposition rate were observed when the distance between the sampling location and the coastal line was about 3000 meters.