| 摘要 |
860,893. Glass compositions. COMPAGNIE DE SAINT-GOBAIN. May 27, 1957 [May 25, 1956 ; May 6, 1957], No. 16818/57. Class 56. [Also in Group XXII] A glass composition, particularly for use as a lubricant in the extrusion of metals at high temperatures, comprises essentially in molecular percentages PzOs + B 2 O 3 29-61% wherein the content of B 2 O 3 is from 0-10% ; Al 2 O 3 + a metal oxide of formula R 2 O 3 10-20% wherein the R 2 O 3 is from 0-5% ; oxides of alkali metals R 2 O 9-33% ; oxides of divalent metals RO 16-20%; the total R 2 O + RO not exceeding 50% and when including PbO, the content of the latter not exceeding 5% Na, K and Li are specified for the alkali metal ; Ca, Ba, Mg, Zn and Pb for the divalent metal and Fe or G for the R 2 O 3 . Particular examples are given.
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