Determination of the amorphous content in quartz and glass mixtures using ARL EQUINOX 100 X-ray diffractometer

Importance of the Topic

Determining the non-crystalline fraction in quartz and glass blends is essential for predicting material performance in sectors such as pharmaceuticals, metallurgy and cement production. The amorphous phase influences properties like bioavailability in drug formulations and mechanical behavior in bulk metallic glasses.

Study Aims and Overview

This application note evaluates the capability of the ARL EQUINOX 100 X-ray diffractometer to quantify amorphous content in mixtures of quartz and glass without the need for external calibration standards. Weight fractions ranging from 10 to 70 percent quartz were tested to assess precision and accuracy.

Methodology and Instrumentation

Mixtures were prepared by ball milling for three minutes at 20 Hz, yielding samples with quartz mass fractions of 10, 30, 50 and 70 percent. Diffraction data were collected in reflection mode using Cu Kα radiation (1.541874 Å), with the sample rotating over three minutes per analysis. Standardless deconvolution algorithms in MAUD and JADE software extracted the amorphous fraction from the diffraction patterns.

Used Instrumentation

The Thermo Scientific ARL EQUINOX 100 features a micro-focus Cu or Co X-ray source (50 W or 15 W) and a curved position sensitive detector that records all diffraction peaks simultaneously. Its low cooling requirements and portability allow rapid deployment across laboratories without specialized infrastructure.

Key Results and Discussion

• For samples with at least 40 percent amorphous content, both MAUD and JADE achieved deviations within ±1.5 percent of the expected values.
• Below 40 percent amorphous fraction, accuracy decreased due to differences in Rietveld deconvolution routines and sensitivity to full-width at half-maximum determination.
• Standardless approaches delivered reliable quantification down to approximately 25 percent amorphous phase; lower levels may require spiking methods for improved precision.

Benefits and Practical Applications

The combination of rapid data acquisition, ease of transport and standard-free analysis makes this approach well suited for routine quality control in industries where amorphous content critically affects material properties. It eliminates the need for extensive reference libraries and lengthy calibration procedures.

Future Trends and Opportunities

Ongoing developments may include refined deconvolution algorithms to enhance accuracy at low amorphous fractions, automated sample handling for higher throughput and application of curved detectors to a broader range of composite systems. Advances in detector technology and data processing could further shorten measurement times and improve sensitivity.

Conclusion

The ARL EQUINOX 100 X-ray diffractometer, combined with standardless deconvolution in MAUD or JADE, provides a robust and rapid method for quantifying amorphous content in quartz-glass mixtures. It offers high accuracy above 25 percent amorphous phase, with spiking recommended for lower fractions.

Reference

• Thermo Fisher Scientific Inc. Application note AN41112 XRAN41112, 2018