Copper-based conductive composites with tailored thermal expansion.

Area of Science:

• Materials Science
• Nanotechnology
• Composite Materials

Background:

• Developing advanced materials with tailored properties is crucial for modern electronics.
• Existing materials often struggle to balance thermal expansion with electrical and thermal conductivity.

Purpose of the Study:

• To create novel metal-matrix composites with tunable thermal expansion coefficients (CTE).
• To achieve high electrical and thermal conductivity in these composites.
• To enable stable operation of electronic devices under thermal cycling.

Main Methods:

• A moderate temperature hot-pressing route was employed.
• Zirconium tungstate (ZrW2O8), a negative CTE material, was incorporated into a copper matrix.
• Copper nanoparticles (NPs) were synthesized and hot-pressed at 500 °C.

Main Results:

• The composites exhibited tunable CTE values ranging from pure copper (16.5 ppm/°C) to below 1 ppm/°C.
• Achieved 92-93% of theoretical copper density after hot pressing.
• Successfully avoided decomposition of ZrW2O8 during processing.

Conclusions:

• The developed hot-pressing method enables the creation of Cu-ZrW2O8 composites with designed CTE and high conductivity.
• These materials are suitable for electrical contacts in semiconductor and thermoelectric devices.
• The tunable CTE and high conductivity offer stable performance under thermal cycling.