Determination of Oxygen and Nitrogen in Reactive/Refractory Metals and Their Alloys* (TC600)

Importance of the Topic

Determining trace levels of oxygen and nitrogen in reactive and refractory metals is critical for controlling material properties such as strength, ductility and corrosion resistance. Accurate analysis supports quality assurance in aerospace, medical, nuclear and specialty alloy production.

Study Objectives and Overview

This application note describes a validated procedure for quantifying oxygen and nitrogen in metals and alloys—Ti, Zr, W, Mo, Ta, Nb, Hf—using the LECO TC600 inert gas fusion analyzer. The method complies with ASTM E-1409, E-1569 and E-1937 standards and outlines sample preparation, calibration and analysis parameters.

Methodology

The inert gas fusion principle is employed: a weighed metal sample is fused in a high-purity graphite crucible under flowing helium. Evolved gases are swept through infrared and thermal conductivity detectors to quantify oxygen (as CO/CO2) and nitrogen (as N2). The procedure includes blank determinations, multi-point calibration with certified metal pins and replicate sample analyses to ensure precision.

Used Instrumentation

• LECO TC600 analyzer with microprocessor control
• Graphite crucibles (782-720)
• Electrode tips (782-721)
• UHP nickel sample baskets (502-344)
• Graphite powder accelerator (501-073)
• Glass accelerator scoop (503-032)
• Tin capsules for powders (501-059)
• Infrared absorption module and thermal conductivity cell

Main Results and Discussion

Tests on titanium pins yielded an average oxygen content of 0.1836 % (SD 0.0011) and nitrogen content of 0.0188 % (SD 0.00029). Zirconium wire results averaged 0.1240 % oxygen (SD 0.0010) and 0.0020 % nitrogen (SD 0.00008). Low standard deviations demonstrate high repeatability and method robustness across sample types.

Benefits and Practical Applications

• High accuracy and precision for reactive and refractory metals
• Compliance with industry standards (ASTM)
• Rapid analysis cycle with automated sample loading
• Versatility across a broad range of alloys and sample sizes

Future Trends and Potential Applications

Advances may include integration of real-time process analytics, miniaturized sensors for in-line monitoring, enhanced software algorithms for automated calibration and data handling, and expansion to other non-metallic matrices. Industry 4.0 integration will drive remote diagnostics and predictive maintenance.

Conclusion

The LECO TC600 inert gas fusion method delivers reliable, reproducible measurements of oxygen and nitrogen in reactive/refractory metals. Adherence to ASTM protocols, combined with precise instrument control, ensures suitability for demanding industrial and research laboratories.

References

1. ASTM E-1409: Standard Test Method for Oxygen Determination in Titanium and Titanium Alloys
2. ASTM E-1569: Standard Test Method for Oxygen Determination in Tantalum
3. ASTM E-1937: Standard Test Method for Nitrogen Determination in Titanium and Titanium Alloys