Determination of Hydrogen in Reactive and Refractory Metals (H836)

Significance of Hydrogen Analysis

Hydrogen content in reactive and refractory metal alloys such as titanium and zirconium critically affects mechanical integrity and service life, requiring precise measurement to prevent hydride formation and embrittlement.

Objectives and Overview

This application note outlines a robust protocol for hydrogen determination by inert gas fusion, covering sample handling, calibration, and analysis to support stringent quality standards in aerospace, medical, and other demanding industries.

Methodology

Sample preparation avoids cold traps due to low hydrogen mobility, focusing on abrasion and controlled sectioning. The workflow includes instrument blanking, calibration using certified reference materials, and sample analysis via an H836 inert gas fusion system equipped with tin flux and graphite crucibles. Key parameters are optimized for helium carrier gas, with adjustments noted for argon use.

Instrumentation Used

• LECO H836 fusion analyzer
• Graphite crucibles (782-720)
• Tin flux pellets (761-739)
• Lower electrode tips (618-376)

Main Results and Discussion

Analysis of NIST 352c reference material yielded an average hydrogen content of 49 ppm with a standard deviation of 0.49 ppm. An unknown titanium sample exhibited an average of 7 ppm hydrogen (s=0.64 ppm), demonstrating method precision and accuracy.

Benefits and Practical Applications

This technique provides reliable hydrogen quantification critical for ensuring alloy performance in high-stress applications, enabling quality control during heat treatment, pickling, and surface finishing processes.

Future Trends and Opportunities

Emerging directions include integration of automated sample handling, adoption of advanced carrier gases for enhanced sensitivity, and linking analytical data with laboratory information management systems to drive process optimization and compliance.

Conclusion

The described inert gas fusion method delivers precise and reproducible hydrogen measurements in reactive and refractory metals, supporting material certification and safeguarding structural integrity.

Reference

• ASTM E1447 Standard Test Method for Determination of Hydrogen in Reactive Metals and Alloys by Inert Gas Fusion
• ASTM D1447 Standard Practice for Flux Ratio in Gas Fusion Analysis
• LECO Corporation Application Note Determination of Hydrogen in Reactive and Refractory Metals Form No 203-821-456 8/22 REV3