The determination of the crystalline content of glass-ceramics

Abstract

The determination of the crystalline content of glass-ceramic materials is complicated by small crystal size (0.1 to 20 μm) as well as by variable crystal composition and morphology. Electron microscope, X-ray diffraction, and chemical separation techniques for quantitative crystallinity determinations can give equally valid results. Electron microscopy, however, is more universal in its application, since identification and synthesis or insolubility of the crystals are not important factors in quantitative results. Replica and transmission electron microscopy are used to determine the crystalline content of complex polycrystalline glass-ceramics. These techniques involve preparation of replicas of selectively etched surfaces as well as thin sections less than 0.1 μm thick. The X-ray diffraction peak-intensity procedure for quantitative crystallinity analysis is demonstrated in glass-ceramics exhibiting extensive crystal solid solution. Chemical separation techniques for quantitatively distinguishing between glass and crystalline phases corroborate electron microscope and X-ray diffraction results. © 1967 Chapman and Hall.