Hydrogen Determination in Copper and Copper Alloys

Significance of the Topic

Hydrogen dissolved in copper during melting can be trapped during solidification, leading to porosity, reduced ductility and diminished electrical and thermal conductivity. Accurate quantification of hydrogen content is therefore essential for quality control in industries such as electronics, plumbing, cookware fabrication and coinage.

Objectives and Overview

This study details a method for determining hydrogen levels in copper and copper alloys using a thermal conductivity based hydrogen determinator. It outlines procedures for sample preparation, calibration and analysis for both solid and powder forms, aiming to deliver reproducible and sensitive results suitable for production laboratories.

Methodology and Instrumentation

Samples of copper or alloy are prepared by abrasion or milling to remove surface contamination. Powder or chip samples are enclosed in tin capsules for analysis. Calibration employs steel pin reference materials or gas dosing for drift correction. The measurement system comprises a LECO RHEN600 or RHEN602 hydrogen determinator featuring an electrode furnace under argon flow and a thermal conductivity detector. Key operating parameters include three outgas cycles, a 90-second analysis delay, integration delay of 40 seconds and furnace currents of approximately 825 to 900 amps depending on the phase. Bulk surface separation is disabled for copper analysis.

Main Results and Discussion

Typical measurements for oxygen-free copper yielded an average hydrogen content of 1.39 ppm with a standard deviation of 0.053 ppm. A copper rod with low oxygen content produced 0.34 ppm H with a 0.031 ppm deviation. Powder samples in tin capsules showed a hydrogen level around 124.3 ppm with 0.70 ppm precision. These results demonstrate the method’s high sensitivity and reproducibility under semi-automatic conditions. Manual loading methods, while feasible, introduce greater variability and higher blank values.

Benefits and Applications

The described protocol offers rapid analysis, minimal sample preparation for solids, and reliable quantification of dissolved hydrogen. It supports quality assurance in copper manufacture, ensuring compliance with industry purity standards and safeguarding the performance of end-use products in electronics, plumbing and biomedical fields.

Future Trends and Potential Applications

Advancements may include automated bulk-surface hydrogen differentiation for alloys, integration of gas dosing for on-line calibration, and connectivity with laboratory information management systems. Expansion of the technique to other metals and alloys can broaden its applicability in materials research and industrial quality control.

Conclusion

The LECO RHEN600 and RHEN602 hydrogen determinators deliver precise, repeatable hydrogen measurements in copper and its alloys. This method ensures material integrity by detecting critical hydrogen levels that can compromise mechanical and conductive properties.

References

• LECO Corporation. Application note on hydrogen determination in copper and copper alloys, Form No. 203-821-305, 2006.