Analysis of Ceramic Molded Products by Thermal Analysis

Significance of the Topic

Ceramic parts are critical in electronics, insulation, and structural applications. Effective removal of organic binders during ceramic manufacturing can reduce energy consumption, shorten production cycles, and prevent defects such as cracks or warpage.

Objectives and Study Overview

This study investigates the influence of atmosphere (air vs. nitrogen) on debinding behavior of injection-molded alumina ceramics. Using combined thermal analysis techniques, the goal was to characterize decomposition temperatures, reaction energetics, dimensional changes, and evolved gas composition to optimize the debinding process.

Methodology and Instrumentation

The analysis comprised three complementary instruments:

• DTG-60 simultaneous thermogravimetric and differential thermal analyzer for mass loss and DTA response.
• TMA-60 thermomechanical analyzer for measuring dimensional changes under controlled temperature ramps.
• DTG-FTIR evolved gas analysis system to identify key gaseous species released during heating.

All measurements were performed on injection-molded alumina specimens (16 mg for DTG, ~5 mm length for TMA) over 30–600 °C at 10–20 °C/min under air or nitrogen.

Main Results and Discussion

DTG-DTA results revealed a rapid weight loss of approximately 14% (binder content) in both atmospheres, but the onset of decomposition occurred at a lower temperature in air. The DTA curve showed a large exothermic peak in air due to oxidative binder decomposition, whereas under nitrogen a small endothermic event appeared around 400 °C.

TMA data indicated initial expansion up to 60 °C (air) and 80 °C (nitrogen), followed by multistage contraction. A pronounced contraction phase commenced near 200 °C, correlating with binder breakdown, and no further dimensional change occurred beyond 400 °C.

DTG-FTIR analysis identified decyl methacrylate evolution at ~690 s, and CO₂ release began at ~220 °C, peaking near 360 °C with a secondary release around 440 °C. These observations map the gas evolution profile and help in tailoring heating rates to avoid internal pressure buildup.

Benefits and Practical Applications

• Detailed thermal and mechanical profiles enable faster debinding cycles while mitigating defect risks.
• Atmosphere selection reduces thermal runaway and dimensional distortion.
• In situ evolved gas identification informs safe heating protocols and environmental controls.

Future Trends and Possibilities

• Integration of real-time sensors and feedback control to dynamically adjust temperature and atmosphere.
• Machine learning models trained on thermal analysis data to predict optimal debinding recipes.
• Miniaturized or portable thermal analyzers for on-site process monitoring in production lines.

Conclusion

Combining TG-DTA, TMA, and evolved gas FTIR provides a comprehensive toolkit for debinding optimization in ceramic manufacturing. This approach allows rapid, data-driven adjustment of process parameters, enhancing efficiency and product quality without extensive sample preparation.

References

1. Tomohiro Wada and Taiki Horino, Development of Atmospheric Gas Technology for Dewax and Sintering in Fine Ceramics Products, TAIYO NIPPON SANSO Technical Report No.29 (2010).