Welding of Small Parts Using Nanocomposite Thermites

1. Welding of Small Parts Using Nanocomposite Thermites Ann Cannella New Jersey Institute of Technology Mentor: Dr. Dreizin

2. Thermites Example of Traditional Welding • Compositions of mixed metal (typically Al) and metal oxide • 2Al+Fe2O3 → 2Fe+Al2O3+heat. • Reactions release large quantities of heat, molten iron, and aluminum oxide • Difficult to ignite • Self-sustaining only for a large amount of thermite mixture • Used traditionally for large scale welding http://www.ameco.net/images/products/thermite_welding_tns.jpg

3. Nanocomposites • Mixture of two or more materials blended on the scale of one billionth of a meter. • Produced by mechanical milling • Large reactive surface areas • React more rapidly and more intensely than larger sized composites

4. Objective • Identify conditions for the thermite welding suitable for joining small parts • Vary • Composition • Mixture density • Scale of mixing between components

5. Nanocomposite Thermites • Al-CuO prepared using Arrested Reactive Milling (ARM) • Blends of varying ratios of Al-CuO and Al or Al-Cuo and Cu prepared in an ultrasonic bath Shaker Mill Crest Ultrasonics

6. Tests Tungsten Wire (diameter .2mm) Copper plates pressed in copper wedge Powerstat Variable Autotransformer

7. Textolite boards covered by copper foil were used as parts to be joined A series of experiments with different compositions prepared and performed ARM powder of 2Al+3CuO Added Al powder Added Cu powder Mixed Al and CuO powders Bonding of molten copper to the copper foil observed in some experiments, but no joining was achieved Reaction was too quick: copper boils and vapor repels joining parts too slow: does not propagate Results

8. Future Work • Press powders into pellets • Remove porosity • Reduce reaction temperature to avoid Cu boiling • Reduce amount of filler by making thin pellets • Use laser to ignite thermites • Overcome ignition difficulties for dense pellets