Oxygen, Nitrogen, and Hydrogen in Refractory Metals

Importance of the Topic

Simultaneous and accurate measurement of oxygen, nitrogen and hydrogen in refractory metals such as titanium and zirconium is critical to ensure mechanical integrity, corrosion resistance and performance in industry sectors including aerospace, medical devices and defense.

Goals and Study Overview

This application note introduces the LECO ONH836 determinator and demonstrates a protocol for simultaneous oxygen nitrogen and hydrogen analysis by inert gas fusion coupled with infrared and thermal conductivity detection. It outlines sample preparation options, method parameters and performance characteristics for solid and powder or chip samples.

Methodology and Instrumentation

Analysis Method
Electronically controlled high power electrode furnace liberates gases under inert carrier gas. Infrared detection is used for oxygen, thermal conductivity detection for nitrogen and hydrogen. Key steps include surface contamination removal by abrading or etching, addition of graphite powder and use of nickel baskets or capsules.

Used Instrumentation and Accessories

• LECO ONH836 Oxygen Nitrogen Hydrogen Determinator
• Graphite crucibles
• Nickel baskets and capsules
• Graphite powder as combustion aid
• Nickel flux for powder and chip samples
• Inert carrier gas supply (helium or argon)

Key Results and Discussion

Solid Samples
Precision of O N H measurements on certified reference materials yielded relative standard deviations below 1.0 for O and N and below 7% for H. Typical cycles complete in under 4 minutes allowing high sample throughput.

Powder and Chip Samples
Use of nibbled nickel flux in capsules optimized recovery. Results on titanium and zirconium alloys matched reference values with standard deviations of <0.005% for O and N and few ppm for H.

Comparison Across Materials

• Titanium alloys achieved O levels around 0.12% N near 0.015% and H near 40 ppm
• Zirconium chips showed O around 0.15% N near 0.0038% and H around 12 ppm
• Tantalum powder yielded O near 0.10% N near 0.003% and H above 110 ppm

Benefits and Practical Applications

• Rapid simultaneous analysis of three critical interstitial elements
• Minimal sample cooling requirements and flexible preparation
• High precision and accuracy suitable for QA QC and R D
• Adaptable to both automation and manual operation

Future Trends and Potential Uses

Looking ahead, integration with automated sample handling, application to broader refractory metal systems and refinement of carrier gas protocols may further improve throughput and detection limits. Coupling with complementary surface analysis could extend capability towards contamination profiling.

Conclusion

The LECO ONH836 determinator provides a robust and efficient solution for simultaneous oxygen nitrogen and hydrogen analysis in refractory metals. Its high power furnace design and dual detection schemes deliver reliable performance meeting industry standards.

References

• ASTM E1447 Determination of Hydrogen in Titanium and Titanium Alloys by Inert Gas Fusion Thermal ConductivityInfrared Detection Method
• ASTM E1409 Determination of Oxygen and Nitrogen in Titanium and Titanium Alloys by the Inert Gas Fusion Technique
• LECO Certified Reference Materials and NIST reference standards