Oxygen in Aluminum and Aluminum Alloys (TC500-Series)

Importance of the Topic

Oxygen content in aluminum and its alloys critically influences electrical conductivity in wire applications and contamination levels during sputtering in integrated circuit target production. Since oxygen forms insoluble aluminum oxide particles, accurate quantification supports quality control and improves device yield.

Objectives and Overview of the Study

This application note describes a semi-automated infrared absorption method for determining oxygen in solid aluminum samples using a LECO TC500-Series analyzer. It outlines sample preparation, calibration procedures, furnace parameters, and typical performance metrics to guide laboratories in routine quality assessment of aluminum and alloy materials.

Methodology

Samples are machined or abraded to remove surface contaminants, rinsed in acetone, and dried before immediate analysis. Approximately 0.1 to 1.0 g of sample is weighed and loaded into a graphite crucible along with a tin pellet, copper chip, and graphite powder. The analyzer operates in semi-automatic mode with these key furnace parameters:

• Purge time 15 s
• Outgas time 15 s, power 6000 W
• Analysis delay 20 s, minimum analysis time 35 s, power 5000 W
• No ramp rates; temperature sustain not required

Calibration and drift correction employ steel reference samples due to limited availability of aluminum oxide standards. Each calibration point is run in triplicate, and blank corrections follow manufacturer instructions.

Used Instrumentation

• LECO TC500-Series combustion infrared absorption analyzer
• Graphite crucible
• Electrode tip assembly
• Tin pellets, copper chips, graphite powder

Main Results and Discussion

Typical oxygen levels measured in aluminum rods ranged from 7 to 10 ppm (standard deviation ~1.1 ppm), while disc samples showed 13 to 20 ppm (standard deviation ~2.8 ppm). The method demonstrates high repeatability and low detection limits suitable for quality control. Key factors affecting accuracy include prompt analysis after sample preparation and consistent furnace conditions.

Benefits and Practical Applications of the Method

• Rapid semi-automated analysis supporting routine QC workflows
• High sensitivity for low ppm oxygen detection
• Minimal sample preparation with common laboratory accessories
• Applicability to wire conductivity checks and sputtering target purity

Future Trends and Applications

Advancements may include integration of in-line monitoring systems for continuous oxygen measurement, enhanced infrared detectors for sub-ppm sensitivity, chemometric calibration models, and further automation to increase throughput. Expansion of reference materials for aluminum oxide will improve calibration accuracy.

Conclusion

The LECO TC500-Series methodology offers a reliable and efficient approach to quantify oxygen in aluminum and its alloys. With straightforward sample preparation, robust calibration procedures, and reproducible results, the method supports critical quality control in wire manufacturing and IC target production.

References

• LECO Corporation Application Note Form No 203-821-362 Oxygen in Aluminum and Aluminum Alloys, 2009