| abstract |
In a high-pressure vapor arc lamp wherein sodium atoms are a principal radiating specie and the arc tube is an alumina or similar ceramic, sodium can react with other substances present including the material of the arc tube itself, resulting in cleanup of sodium. This is prevented by introducing a certain metals, alloys, or metal compounds into the lamp whose function is to prevent the formation of sodium aluminate or related compounds which are directly responsible for the sodium cleanup. This requires a negative free energy or reaction for the equation of the form: |