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.