分别采用喷水法、盐雾法、电解法和固体污层法对绝缘子的铁帽、钢脚进行电解腐蚀模拟试验研究,并对不同试验方法的等效性和可行性进行分析。通过与金属附件的现场腐蚀情况进行对比,并综合考虑各种方法的可操作性,推荐采用喷水法和盐雾...分别采用喷水法、盐雾法、电解法和固体污层法对绝缘子的铁帽、钢脚进行电解腐蚀模拟试验研究,并对不同试验方法的等效性和可行性进行分析。通过与金属附件的现场腐蚀情况进行对比,并综合考虑各种方法的可操作性,推荐采用喷水法和盐雾法进行绝缘子金属附件电解腐蚀的模拟试验研究。采用喷水法进行铁帽腐蚀试验时,盐溶液的电导率取8~10 m S/cm(20℃),喷水流量控制在8~10 L/h范围内;进行钢脚腐蚀试验时,溶液电导率取2~3 m S/cm(20℃),喷水流量为2~3 L/h。采用盐雾法进行试验时,盐水溶液的电导率调配为10~12 m S/cm,单个喷嘴的喷雾流量为0.25~0.4 L/h。展开更多
Aluminium alloy（AA） 2024 is an important engineering material due to its widespread use in the aerospace industry. However, it is very prone to corrosion attack in chloride containing media. In the present investiga...Aluminium alloy（AA） 2024 is an important engineering material due to its widespread use in the aerospace industry. However, it is very prone to corrosion attack in chloride containing media. In the present investigation, AA2024 aluminium alloy rolled plates of 5 mm in thickness were friction stir welded. Corrosion performances of the specimens were evaluated by conducting salt fog tests in Na Cl solution at different p H values, chloride ion concentrations and spraying time. In addition, an empirical relationship was established to predict the corrosion rate of friction stir welds of AA2024 aluminium alloy. A central composite rotatable design including three factors and five levels was used to minimize the number of experiments. Response surface methodology（RSM） was used to develop the relationship. The corrosion rate decreased under neutral p H conditions. The corrosion rate increased in acidic and basic conditions. It was also found that the corrosion rate decreased with the increase of spraying time, but the corrosion tended to be uniform with the increment of time and with the increase in the chloride ion concentration, and the corrosion rate increased in the salt spray corrosion test.展开更多
This study aims to evaluate the presence of free chlorides by the silver nitrate colorimetric spraying method in mortars made with Portland cement CP II Z-32. In order to make an assessment beyond the qualitative anal...This study aims to evaluate the presence of free chlorides by the silver nitrate colorimetric spraying method in mortars made with Portland cement CP II Z-32. In order to make an assessment beyond the qualitative analysis, a calculation of the contaminated areas by free chlorides was performed by measuring the regions using a computer image analysis software （IMAGEJ）. The experimental part of the research involved samples of 5 cm x 10 cm of mortar and 0.1 M solution of silver nitrate in distilled water. The mortar samples were made with cement CP II Z-32 with the following concentrations of chloride incorporated into the mixing water： 0%0, 0.4%, 0.6%, 0.8%, 1.0% and 2.0%, in relation to the mass of cement, totaling 108 samples. The average of percentage results from the contaminated area of the series of samples was respectively 0%, 14.9694%, 19.7444%, 46.0239%, 62.3311% and 96.0083% in relation to the total area, concluding that the method of silver nitrate spraying is applicable and that the white color indicates the presence of chloride ions and other possible aggressive salts to the structure or the concrete.展开更多
文摘分别采用喷水法、盐雾法、电解法和固体污层法对绝缘子的铁帽、钢脚进行电解腐蚀模拟试验研究,并对不同试验方法的等效性和可行性进行分析。通过与金属附件的现场腐蚀情况进行对比,并综合考虑各种方法的可操作性,推荐采用喷水法和盐雾法进行绝缘子金属附件电解腐蚀的模拟试验研究。采用喷水法进行铁帽腐蚀试验时,盐溶液的电导率取8~10 m S/cm(20℃),喷水流量控制在8~10 L/h范围内;进行钢脚腐蚀试验时,溶液电导率取2~3 m S/cm(20℃),喷水流量为2~3 L/h。采用盐雾法进行试验时,盐水溶液的电导率调配为10~12 m S/cm,单个喷嘴的喷雾流量为0.25~0.4 L/h。
文摘Aluminium alloy（AA） 2024 is an important engineering material due to its widespread use in the aerospace industry. However, it is very prone to corrosion attack in chloride containing media. In the present investigation, AA2024 aluminium alloy rolled plates of 5 mm in thickness were friction stir welded. Corrosion performances of the specimens were evaluated by conducting salt fog tests in Na Cl solution at different p H values, chloride ion concentrations and spraying time. In addition, an empirical relationship was established to predict the corrosion rate of friction stir welds of AA2024 aluminium alloy. A central composite rotatable design including three factors and five levels was used to minimize the number of experiments. Response surface methodology（RSM） was used to develop the relationship. The corrosion rate decreased under neutral p H conditions. The corrosion rate increased in acidic and basic conditions. It was also found that the corrosion rate decreased with the increase of spraying time, but the corrosion tended to be uniform with the increment of time and with the increase in the chloride ion concentration, and the corrosion rate increased in the salt spray corrosion test.
文摘This study aims to evaluate the presence of free chlorides by the silver nitrate colorimetric spraying method in mortars made with Portland cement CP II Z-32. In order to make an assessment beyond the qualitative analysis, a calculation of the contaminated areas by free chlorides was performed by measuring the regions using a computer image analysis software （IMAGEJ）. The experimental part of the research involved samples of 5 cm x 10 cm of mortar and 0.1 M solution of silver nitrate in distilled water. The mortar samples were made with cement CP II Z-32 with the following concentrations of chloride incorporated into the mixing water： 0%0, 0.4%, 0.6%, 0.8%, 1.0% and 2.0%, in relation to the mass of cement, totaling 108 samples. The average of percentage results from the contaminated area of the series of samples was respectively 0%, 14.9694%, 19.7444%, 46.0239%, 62.3311% and 96.0083% in relation to the total area, concluding that the method of silver nitrate spraying is applicable and that the white color indicates the presence of chloride ions and other possible aggressive salts to the structure or the concrete.
