Chromium-contg glass - for electronic components

摘要

Glass consisting mainly of a mixture of mineral oxides plus a small amount of a chromium cpd. as oxidant is prepd. by melting the constituents at 677-816 degrees C homogenising, quenching and grinding so that 100% pass 0.149 mm and 76% pass 0.44 mm sieve. Pref. composn. is 8-14% ZnO, 8-12% B2O3, 70-80% PbO, 1-5% SiO2, 1-5% BaO or Al2O3 plus 0.002 to 0.50% (0.02-0.06%) chromic acid. Used for sealing electronic devices esp. television tubes in which case CaF2 is added.