SILVER TREE

In this paper, AgNO3 (silver nitrate) solution was used as liquid elec trode to accelerate the growth of water trees in polyethylene. It was found that water trees grown in AgNO3 solution can be colored spontane ously during their formation, their areas are brownish-yellow, and the y grow fast. Scanning electron microscopy (SEM) revealed microchannels in the AgNO3-grown water tree with diameters from 0.2 to 0.5 mu m. In fact,these microchannels are possibly filled with metallic silver red uced from silver ions, and these water trees are referred to as 'silve r trees'. The structure of the silver trees is studied and analyzed in comparison with sulfide trees and blue water trees. The effects of si lver ions (Ag+) in the silver tree region are investigated and a compa rison is made with other ions such as KS, Na+, Mg++, and Cu++ in water trees. The trees from AgNO3 solution grow much faster than trees from the other solutions. Finally, the mechanism of the formation of silve r trees is suggested.