AN ENVIRONMENTAL FRIENDLY, INDUSTRIAL PECVDTREATMENT FOR ANTI-TARNISHING AND ANTI-WEARCORROSION OF SILVER

摘要

Tarnishing of silver (and its alloys) in wet atmosphere containing sulphide is a persistent problem. Theaim of this work is to present an anti-corrosion and anti-wear treatment carried out in an industrialPlasma Enhanced Chemical Vapor Deposition (PECVD) device. A treatment consisting in a depositedprimer (P) layer followed by the growth on the sample surfaces of nano-layers of SiOx was studied. Afterone week of immersion in the test solution (aerated 0.5 M NaCl at 20℃) all different treated samplesmaintained their glossy aspect, but the electrochemical tests revealed that only the specimens treated withP + 2 μm SiOx maintain the requested anti-corrosion behavior, even if the other samples improved theircorrosion performance. The hardness and the elastic modulus both of the films and of the silver substratewere determined by load-depth nano-indentation measurements. The results also highlighted a significantincrease in the hardness value (Berkovich) of the coated samples compared to that of the uncoated silversubstrate.