薄液膜下航天器异种材料电偶腐蚀兼容性

Galvanic Compatibilities of Spacecraft Dissimilar Materials Under the Thin-layer Electrolytes

针对文昌航天发射中心航天器产品的腐蚀评价需求,提出一种基于薄液膜三电极系统的航天器异种材料电偶腐蚀兼容性评价方法.设计了一套薄液膜三电极系统,在控温控湿的薄液膜条件下对5种航天器材料进行了电偶腐蚀试验.结果表明:由于欧姆电阻和阴阳极金属极化率的影响,薄液膜比水溶液全浸更适宜作为航天器异种材料电偶腐蚀兼容性评价的试验条件,电偶电流密度与试验条件明显相关.航天器异种材料电偶腐蚀兼容性评价应使用控温控湿的薄液膜三电极系统进行,并以电偶电流密度作为电偶腐蚀兼容性的评价判据.

A test method, based on the three-electrode system under a thin-layer electrolyte, for determining the galvanic compatibilities of spacecraft dissimilar materials is proposed,to fulfill the needs of corrosion evaluation of the spacecraft launched from Wenchang Satellite Launch Center. A threeelectrode system under a thin-layer electrolyte was designed,and galvanic corrosion tests on five types of spacecraft materials were conducted under a temperature and humidity controlled thin-layer electrolyte.Results show that owing to the ohmic resistance and the polarization extent of anodic and cathodic metals,thin-layer electrolytes are more favored environmental conditions for assessing the galvanic compatibilities of spacecraft dissimilar materials than aqueous solutions,and there is a strong correlation between galvanic current densities and environmental conditions. This work suggests that the three-electrode system under a temperature and humidity controlled thin-layer electrolyte and the criteria of galvanic current density should be used to assess the galvanic compatibilities of spacecraft dissimilar materials.