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Development of a Quantitative XRF Method for High Purity Refractory Materials

Requirement

A manufacturer of high-performance refractory ceramics, specialising in the production and innovation of Tin Oxide and Zirconia ceramics, needed accurate analysis and cost-effectiveness.

The most common and effective methods for testing the chemical analysis of Zirconia and Tin Oxide ceramics are:

• X-ray Fluorescence (XRF) Spectrometry
• Inductively Coupled Plasma (ICP) Spectroscopy

ICP analysis requires suitable reference materials for calibration, especially when quantifying multiple elements with high accuracy. For Tin Oxide and Zirconia refractory ceramics, there are no certified reference materials available. As a result, ICP can only provide restricted elemental coverage for tin and Zirconia-based refractory systems.

Challenge

Many companies rely on ICP analysis, which is costly, time-consuming, and limited in elemental scope. Analysis of Tin and Zirconium Oxide, even using ICP, is difficult.

Analysis of Tin Oxide and Zirconium Dioxide presents significant challenges:

• No certified reference materials exist for high-purity Tin and Zirconium Oxide.
• The extremely high melting point of Zirconium Dioxide at 2715°C makes fused bead dissolution difficult.
• Sn-based refractories often include Ceric Oxide, Niobium Pentoxide and Tungsten Trioxide, all of which require long fusion times.
• At greater than 90 weight percentage (wt%) oxide, fused bead preparation becomes extremely slow and may fail without multiple re-melts.

Project Summary

Researchers from our Advanced Materials Characterisation Centre developed and refined a complete quantitative X-ray Fluorescence (XRF) method for high-purity Aluminium, Aluminium-Silicon, Zirconium, and Tin Oxide matrices.

We developed this methodology by producing our own high-purity synthetic reference materials, carefully designed to match real refractory compositions.

These custom standards required extensive preparation, multiple fusion cycles, and precise blending to achieve true homogeneity.

• Calibration bases were established using Fluxana RawProF standards containing 21 oxides.
• For Zirconium Oxide and Tin Oxide systems, concentrations were extended to 100 wt%, exceeding the 60 wt% limit of conventional reference materials.
• High-purity oxides (Zirconium Oxide, Tin Oxide, Silicon Dioxide, Copper Oxide, Antimony Trioxide, Niobium Oxide, and Cerium Oxide) were blended to create synthetic standards from 0–100 wt%, with Zirconium Oxide and Tin Oxide levels focused between 90–100 wt%, matching real-world products.
• Due to the slow dissolution of high-melting oxides, fused beads required multiple re-melts in an electric fusion system.
• Each batch of standards was homogenised in a 3D dynamic mixer to ensure uniformity and maximise analytical precision.
• Calibration curves were developed for all client-requested elements, with the flexibility to add new elements by preparing additional synthetic standards.

Outcome

This XRF quantitative technique delivered:

• High accuracy and repeatability for all target oxides, including challenging compositions such as >90 wt% Zirconium Oxide and >95 wt% Tin Oxide.
• A validated capability for analysing Cerium Oxide, Niobium Oxide, Copper Oxide, Tungsten Trioxide, and other high-melting additives.
• A flexible analytical platform, allowing expansion to new oxides or trace elements as required by refractory manufacturers.
• Reliable fused bead production for highly refractory materials through multi-stage re-melting protocols.
• This XRF quantitative method covers the full suite of elements required for Tin and Zirconium based refractory products
• It has a high degree of accuracy for both the bulk and trace elements, meaning it can detect low concentrations of impurities.
• It provides a cost-effective alternative to ICP for high-purity refractory materials, offering faster turnaround and broader elemental coverage.

This XRF method provides refractory manufacturers a practical and accurate means for routine XRF analysis of advanced refractory materials — something previously considered impractical due to the absence of suitable reference materials and the extreme melting behaviour of Zirconium Oxide and Tin Oxide based systems.

Advanced Materials Characterisation Centre

The Advanced Materials Characterisation Centre is an international centre for steel and metals characterisation and investigation, including failure analysis and forensic analysis, along with research, development and innovation.

More about our Advanced Materials Characterisation Centre

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