Chemical reaction phenomena in a Sc-Na halide lamp

摘要

References(10) To improve lumen maintenance of the Sc-Na halide lamps, it is necessary to have a knowledge of tungsten tranport process. In this paper, two Scl3 reaction phenomena which initiate tungsten transport are described. The one is phenomenon which has relation with the reaction between Scl3 and SiO2,the arc tube material. The other is phenomenon which has relation with the reaction between Scl3 and ThO2,the electrode emitter. Tungsten moves from the electrode tip to the tube wall as the result of the first reaction. Tungsten accumulates onto the electrode tip as the result of the second reaction. These chemical phenomena were related to the chemical analysis of black deposit on the wall, the observation of electrode tip deformations, the estimation of Th amounts in the arc and the comparison of electrode tip temperatures.