电镀件的真空放气特性研究

材料的真空放气特性与其表面状态息息相关,本文采用小孔流导法,比较研究了电镀件镀层材料、镀层厚度和不同基底材料下的放气特性。从实验结果可以看出,在所测试的24 h时间内,材料的表面放气仍占主导作用,基底材料和镀层厚度对材料放气率的时间变化趋势和最终放气率基本没有影响。而镀层材料对电镀件的放气率影响较大,同一时间点,电镀件的放气率高于未电镀件;电镀件中,镀锌件的放气率最高。无论电镀与否,未烘烤样品放出的气体组分中H₂O含量最高,其次有H₂、N₂/CO、CO₂和O₂等。而相比其它电镀件,镀锌件放出的H₂O最多。电镀件放出过量的水蒸气可能会影响含钨灯丝的热阴极电离规读数的准确性。真空系统中应尽量避免使用电镀锌件。

Vacuum Outgassing Characteristics of Electroplated Parts

The vacuum outgassing characteristics of materials are closely related to their surface states.In this paper,the outgassing rates and components of electroplated parts under different coatings,coating thickness and substrate materials are comparatively tested using the throughput method.It can be seen from the experimental results that,during the test time of 24 h,the outgassing from the material surface is still dominant,and the substrate material and coating thickness almost have no effect on the final outgassing rates.However,the coating material has a great influence on the outgassing rate of the electroplating part,with the value of the electroplated part being higher than that of the un-electroplated part at the same pumping time.Moreover,compared with other electroplated parts,galvanized parts have the highest outgassing rates.Whether a part is electroplated or not,water vapor accounts for the majority of its released gases.Besides,H₂,N₂/CO,CO₂ and O₂ are also outgassed.And compared with other electroplated parts,the amount of H₂O released by galvanized parts is the highest.The excess water vapor from electroplated parts may affect the reading of the hot cathode ionization gauge with W filament.The zinc plating part should be avoided in a vacuum system.