Preliminary study on removal of powdery bronze rust by low temperature plasma in a reducing atmosphere
Bronze ware,having high historical,artistic and scientific value,plays an important role in metal cultural relics.However,due to the characteristics of natural materials themselves and the influence of the burial environment,most bronze artifacts unearthed from archaeological sites or cemeteries have been seriously degraded and corroded.The corrosion of bronze ware can be divided into two types-harmful rust and harmless rust;the latter is relatively stable and harmless to bronze artifacts.However,"powdery rust"is severely detrimental to bronzes,and can make the bronzes crumble and rot,thereby seriously affecting the life of the relics.Furthermore,powdery rust also has a certain spreading power,which can cause damage to the bronze relics themselves and the neighboring ones.Therefore,we attempted for the first time to introduce low-temperature plasma technology as a means of removing powdery rust from bronzes.Bronze samples with powdery rust on the surface were prepared by electrochemical corrosion.Then the samples were treated with low temperature plasma in a reducing atmosphere.Comparison of data of bronze samples before and after the treatment shows that the low-temperature plasma technology could effectively remove chloride ions in the powder rust.This study could provide a new idea and method for the conservation of bronze relics.