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POWDER METHOD FOR MEASUREMENT OF CHEMICAL DURABILITY OF GLASS *
Author(s) -
Tooley F. V.,
Parmelee C. W.
Publication year - 1940
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1940.tb14195.x
Subject(s) - durability , particle (ecology) , materials science , sodium , microscope , mineralogy , composite material , analytical chemistry (journal) , chemistry , optics , chromatography , metallurgy , oceanography , physics , geology
A bstract From the standpoint of a strictly quantitative approach to the problem of measuring the chemical durability of glass, there is need for (1) a method to measure the surface area of irregularly shaped particles that is independent of their chemical composition and surface conditions and (2) methods to measure the actual ions present in extracts from durability tests. A method of measuring (1), that is, the surface of irregularly shaped particles, has been developed, based on the principle thatareas of projected images of a convex particle as measured from n random positions approaches the absolute surface area of the particle as n increases. Particles to be measured were mounted in random orientation by sprinkling them on a transparent plastic mounting medium applied in a thin film on a glass slide. After magnifying with a projection microscope and tracing the areas, the final areal measurements were made planimetrically. The procedures for measuring small concentrations of sodium and silica occurring in durability extracts were tested and were found to be applicable to the problem of measuring the extent of the attack. The procedure for determining sodium is to precipitate and weigh the triple salt, sodium zinc uranyl acetate, (UO 2 ) 3 ZnNa(CH 3 COO) 9 .6H 2 O; the procedure for silica involves the production in acid solution of silicomolybdate blue by reduction of silicomolybdate yellow with sodium sulfite and by a photometric comparison of the color developed with a standard series. By the application of these methods in actual durability tests, it is shown that two equal volumes of the same glass collected between the same limiting screens exhibit a measured difference in surface per unit volume, which correlates closely both with chemical attack and with the positions of surface distribution curves. The evidence of this investigation corroborates the view that closer specification of the conditions under which the glass grains are prepared is desirable and that accurate determination of sodium and silica is practicable in very dilute solutions obtained in durability tests.