Oxygen and Hydrogen in Copper and Copper Alloys

Importance of the Topic

Copper and its alloys underpin the electrical conductor industry owing to their cost-effective combination of mechanical strength, surface quality, and exceptional conductivity. Monitoring residual oxygen and hydrogen is crucial because oxygen impacts electrical performance and hydrogen embrittlement. Precise measurement of these elements ensures material quality, reliability, and longevity in critical applications such as power transmission and electronics.

Objectives and Study Overview

This application note details a robust protocol for simultaneous quantification of oxygen and hydrogen in copper and its alloys using inert gas fusion with infrared detection. The goals are to present sample preparation techniques, instrument setup, calibration routines, and method parameters optimized on the LECO OH836/ONH836 analyzers, demonstrating repeatability and accuracy across a range of copper grades and sample forms.

Methodology and Instrumentation

Sample preparation involves mechanical abrasion to remove surface oxides, followed by solvent rinsing to minimize contamination. Two workflows are described:

• Solid samples: 1–2 g of prepared copper into graphite crucible with tin pellet.
• Chip samples: ~1 g of chips encapsulated in tin capsule then placed in crucible.

Analysis proceeds through a blank measurement, drift correction using nickel-plated copper and steel standards, and sample runs. Key method parameters include defined integration delays, baseline periods, furnace currents, and cycle counts, optimized for helium carrier gas.

Used Instrumentation

• LECO OH836/ONH836 inert gas fusion analyzer
• Graphite crucibles 782-720S
• Tin capsules 502-040 and tin pellets 764-242
• Electrode tips 782-721 and 618-376 (for automation)
• Calibration standards: LECO nickel-plated copper pins, steel pins, NIST/BCR references

Main Results and Discussion

Repeated analyses of abraded and as-received solid samples yielded oxygen values from ~0.0075% to 0.0581% and hydrogen from 0.13 to 0.24 ppm with RSDs below 1.5%. Chip samples demonstrated consistent repeatability (O ~0.0415% or 0.0247%, H ~5.7 or 0.5 ppm). Single-point calibrations forced through the origin provided linear, accurate quantification across tested ranges.

Benefits and Practical Applications of the Method

• High precision and low detection limits for QC and R&D in metallurgy.
• Minimal sample preparation and rapid analysis cycles (~3.5 min).
• Automated cleaning options reduce manual intervention.
• Applicable to diverse copper grades and sample geometries.

Future Trends and Possibilities

Advances may include integration with Industry 4.0 data systems, improved carrier gas flexibility (e.g., argon optimization), enhanced automation software, and further reduction of sample mass requirements. Emerging detection technologies could boost throughput and sensitivity.

Conclusion

The outlined inert gas fusion infrared method facilitates reliable, accurate determination of oxygen and hydrogen in copper and alloys. Its robustness, repeatability, and adaptability make it an essential tool for material qualification and process control in electrical and industrial metallurgical settings.