【作者】 徐安桃；

【导师】 宋诗哲；

【作者基本信息】 天津大学 ， 应用化学， 2008， 博士

【摘要】 军用车辆长期在风沙、雨雪、潮湿、盐雾等恶劣的气候条件下使用,不同程度地受到环境的影响而引起腐蚀。本论文针对军用车辆涂层防护性能的检测与评价和冷却系统金属材料的腐蚀行为两方面开展研究,主要研究内容如下:分析了军用车辆涂层失效的影响因素,对车辆常用的军绿色涂层和黑色防锈涂层的防护性能进行了研究,研究表明即使表面观察完好的涂层,其涂层性能也存在很大差异。由此进行了车辆涂层不同破损程度的模拟研究,建立了各电化学特征参数Rf,Ζfmin和ΖAVG随涂层破损程度系数K的变化规律曲线,为涂层的现场检测与评价提供理论依据。对军用车辆涂层进行了现场实车测试,研究了车体涂层不同失效程度的EIS特征,通过提取低频段(10-2Hz-1Hz)的模值,建立了车体涂层实车测试与部件单独测试模值的平均值Z1和Z2之间的关系曲线,作为现场实车测试的校正曲线,提出评价指标,并尝试性的对多种军用车型涂层状态进行了现场评价。模拟车辆冷却系统腐蚀环境,对发动机冷却系统金属材料的腐蚀行为进行了研究。结果表明铸铁在三种冷却溶液中的腐蚀速度开始随着工作温度的升高而上升,50℃左右时腐蚀速度达到最大,然后稍有下降;铸铝在三种冷却溶液中的腐蚀速度开始随着温度的升高而上升,其变化速度为先快后慢;黄铜在“自来水”和“防冻液”中,其腐蚀速度开始随温度的升高而下降,65℃时腐蚀速度最小,温度继续升高,腐蚀速度变快。黄铜在“浓缩水”中,其腐蚀速度随温度的升高而加快,50℃左右时达到最大,温度继续上升,腐蚀速度基本不变。研究结果表明,长期不更换冷却溶液对军用车辆冷却系统的腐蚀影响很大。研究了Cu/Fe和Cu/Al电偶对组成不同的面积比,在不同的冷却溶液和不同工作温度时的电偶腐蚀行为,进行了Cu/Fe和Cu/Al电偶对的电偶腐蚀规律分析。结果表明,随着电偶对阴阳极面积比的不同,电偶腐蚀规律不同,面积比小于1时,电偶电流的电流密度与面积比之间遵从较好的半对数直线关系;面积比大于1时,则比较复杂。冷却系统金属发生电偶腐蚀时,偶合电位在工作条件下,大部分向阳极金属的腐蚀电位靠近。在冷却系统工作温度范围内,随着温度的升高,电偶电流增加,冷却系统不宜在过高的温度下工作。更多还原

【Abstract】 Military vehicles(MV) were long-term used in the bad weather,such as sandstorm,rain-snow,wet and salting fog. These factors can cause serious corrosion. The behavior of corrosion concerns many factors. In addition to natural environment, vehicle’s usage and designing aspects also were involved. In this thesis,the vehicle corrosion problem were studied from two aspects. One is the evaluation of the performance of protective coating,the other is based on studying the corrosion of cooling system’s metal in different working temperature and liquid. The according measures were usually adopted after the question occurred,because of the two aspects are easy to be ignored,and the result is the increase of the cost of the use and maintain of military vehicle. This paper focus on the test and evaluation of the performance of protective coating and the corrosion of cooling system’s metal. The main research contents are as follows:The influence factors of the failure process of military vehicles coating were analyzed,and researching on the performance of green and black protective coating of the military vehicles.The results manifest that the coating’s performance is quite different from each other,even if it seems like perfect from the surface. The simulation of various degrees of the damages is presented,the coatings sample of various degrees of the damages were made and electrochemistry test was carried out,the data is processed by the software of Zsimpwin,and many electrochemistry parameter such as Rf,Zfmin and ZAVG are extracted,the change curve of these electrochemistry parameters with the coefficient K of the coating’s damage degree is built and analyzed,and provide a theory clue for field testing and evaluation.The field test of military vehicles coating is presented,the EIS of coatings of various damages were analyzed. The model value of the low frequency was extracted,and the relationship curve of average value Z1 and Z2 of the model value of real vehicle test with bodywork coatings and the single parts is built and considered as the adjustment curve for real vehicle test in the theater. Estimate index is brought forward,and the field evaluation of the performance of coating using EIS are carried out,and try to evaluate various coatings. The EIS analyze of the coatings with different damages manifest that coating’s performance is different from each other,even though the surface seems alike. The result show that efficient test and evaluation of military vehicle’s coatings and maintain accordingly is very important to improve the efficiency of vehicles.Simulating cooling system’s environment,the test selects customary metals cooling system usually adopted and three liquids to make the electrochemistry test according different temperature,and analyzes the corrosion of engine cooling system’s metal. The result shows that the corrosion rate of cast iron increased with the temperature increasing in the three liquid,and the rate obtains a maximum level at 50℃,then when temperature increased,the corrosion rate slightly decreased; the corrosion rate of aluminum increased with the temperature increasing in the three liquid; the corrosion rate of brass in the coolant decreased with the temperature increasing, and has a minimum at 65℃,then increased with the temperature increasing,but in the other liquid the corrosion rate of brass reached a maximum at 50℃,then the corrosion rate kept stable. The result manifests that if the replacement of cooling fluid not in time for long time,it will badly corrode the cooling system of military vehicles.According to different cooling fluid and temperature with the various area ratio composed by Cu/Fe and Cu/Al,the galvanic corrosion has been studied and the galvanic current is tested,and the rule of galvanic corrosion is analyzed. The results show that the rules vary with the area ratio of galvanic corrosion’s different poles. When the area ratio below or above 1,the rule will change accordingly. If the ratio is below 1,the relationship between galvanic density and area ratio is half logarithm linearity; if the ratio above 1,the relationship is very complex.Couple electric potential usually close to corrosion potential of anode metal as the galvanic corrosion of cooling system metal happen. Due to the electric current increase,with the raise of temperature in the temperature range,so the cooling system should not work for a long time under the condition of higher temperature.更多还原