New Interpretation of X-ray Diffraction Pattern of Vitreous Silica

Shangcong Cheng

doi:10.3390/ceramics4010008

Abstract

The striking feature of X-ray diffraction pattern of vitreous silica is that the center of its intense but broad ring is located at nearly the same position as the strongest diffraction ring of β-cristobalite. Two fundamentally different explanations to the diffraction patterns were appeared about 90 years ago, one based on the smallest crystals of β-cristobalite and the other based on the non-crystalline continuous random network. This work briefly outlines the facts supporting and objecting these two hypotheses, and aims to present a new interpretation based on a medium-range ordering structure on the facets of clusters formed in the glass transition process. It will be shown that the new interpretation provides a more satisfactory explanation of the diffraction pattern and physical properties of silica glass, and offers considerable valuable information regarding the nature of glass and glass transition.

Highlights

When X-ray or electron beams encounter a crystalline material, they are diffracted by the planes of the atoms within the crystal
This work will briefly outline Randall’s crystallite hypothesis and Warren’s continuous random network hypothesis. This serves as background and contrast to a new interpretation of the silica glass diffraction pattern based on the formation of nanoflakes, which are the mediumrange ordering structures in vitreous silica
Warren et al concluded that the interpretation of the diffraction pattern of vitof vitreous silica is in complete agreement with the conclusions of Zachariasen’s continuous reous silica is in complete agreement with the conclusions of Zachariasen’s continuous random network (CRN) theory illustrated in Figure 3 [8]

Summary

Introduction

When X-ray or electron beams encounter a crystalline material, they are diffracted by the planes of the atoms within the crystal. A convenient way to interpret the vitreous silica diffraction patterns is to compare them with that of β-cristobalite. Both diffraction patterns are ring-shaped, and the center of the diffraction ring of vitreous silica in Figure 1a and the strongest ring of β-cristobalite in Figure 1b are located at nearly the same position. This work will briefly outline Randall’s crystallite hypothesis and Warren’s continuous random network hypothesis This serves as background and contrast to a new interpretation of the silica glass diffraction pattern based on the formation of nanoflakes, which are the mediumrange ordering structures in vitreous silica.

Previous Interpretations from thewere

The microphotometer

Cluster Formation in Vitreous Silica

Experimental datadata associated withwith in the factor

The Stabilized Structure—Nanoflakes

Concluding Remarks