Analysis of Glass by X-Ray Fluorescence

ARL OPTIM’X WD-XRF Spectrometer

Introduction

The simplest form of glass is the single component fused silica (SiO2). However it is both difficult to process and expensive. To reduce these difficulties, some other oxides are added imparting specific properties to the resultant glass. Most of glasses are composed of about 70 % silica, which is a glass former, soda as a flux in the form of carbonate and sulfate (about 14 %), and lime as a stabilizer in the form of limestone (about 10 %). Other types of oxides like alumina or magnesia improve the physical characteristics of glass, particularly the resistance to atmospheric conditions.
In-depth coloring is obtained by incorporation of various metallic oxides: oxides of chromium, iron, manganese or copper.

Instrumentation

An ARL OPTIM’X XRF spectrometer from Thermo Electron Corporation has been used to derive limits of detection and precision for the analysis of glasses. The ARL OPTIM’X is a wavelength dispersive system which  provides superior resolution and light elements capability. It is fitted with an Air-cooled Rh End-Window Tube with thin Be window (0.075 mm) and has a maximum power of 50 Watts. Thanks to close coupling between the X-ray tube anode and the sample the performance of the ARL OPTIM’X is equivalent to a 200W conventional WD-XRF instrument. The instrument can be equipped with the unique SmartGonio™, a series of Multichromators™ or both. Table 1 shows limits of detection for various elements in soda-lime glasses prepared as pressed powders.

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