When 315w ceramic metal halide lamp is working, there will be strong convection in the arc tube due to the strong gas temperature gradient. The arc tube is usually filled with excessive metal halide pellets, which evaporate partly at high temperature and exist partly in the form of molten salt, and eventually reach equilibrium. Corrosion of ceramic tube wall of 315w ceramic metal halide lamp is mainly caused by two factors: The first is corrosion caused by the reaction of vapor metal halide salts with pipe wall materials. Second, metal halide molten salt deposits in the cold end, which corrodes the cold end tube wall.
In addition to the corrosion of vapor phase relative to the ceramic wall of 315w ceramic halide lamp
, the metal halide molten salt also corrodes the wall. However, the mechanism of this corrosion is still unclear. The corrosion of metal halide molten salt on the wall of quartz tube is due to the phase transformation of SiO 2 from glass to crystal phase in molten salt. However, the corrosion mechanism of molten salts on PCA pipes is still uncertain, but it is proposed that the corrosion mechanism is independent of the structural change of PCA. Usually molten salts are deposited at the cold end of the inner tube wall. Serious corrosion of molten salts on the tube wall may lead to whitening or even leakage of the tube wall.