GB1178803A - Glass - Google Patents

Abstract

1,178,803. Luminescent materials. OWENSILLINOIS Inc. 22 May, 1968 [25 May, 1967], No. 24322/68. Addition to 1,113,101. Heading C4S. [Also in Division C1] A transparent, uniformly coalesced, homogeneous, luminescent glass is made by uniformly compacting an intimate, homogeneous, anhydrous mixture of non-crystalline SiO 2 particles of maximum dimension 5000 nm., and a small amount of at least one luminescent activator, being an oxide other than a rare earth oxide, to form a coherent body which is heated in vacuo at a non-devitrifying temperature to sinter. The particle size of the SiO 2 may be 10-5000 nm. There are 5-5000 atoms of metal or metalloid in the oxide per million Si atoms. The luminescent activator may be an oxide of, e.g., Sn, Sb, Zn, Ni, V, Mn, U, Cu, Ag or As. The sintering temperature may be 1000-1750‹ C. The body to be sintered can be made by dehydrating particulate vitreous silica and forming a slurry or paste by mixing with water, alcohol or acetone which may contain the dissolved oxide or precursors; a precipitant, e.g. aqueous ammonia, may be added to precipitate the oxide or hydroxide. The paste is then dehydrated, pulverized and fired. A small quantity of liquid, e.g. water, is then added to increase cohesion and the dampened powder is formed by pressing, e.g. at 100 p.s.i.g. or higher. The pressed form, which may remain in the die, is then fired in vacuo.