Tailoring Ni–Al Powder Composition by Ultrasonic Atomization

Ultrasonic atomization is an attractive technique for the production of small batches of alloy powders due to its ability to generate spherical particles with a narrow particle size distribution. This makes the process particularly suitable for laboratory-scale alloy development and research applications. However, only limited information is available regarding changes in chemical composition during ultrasonic atomization, although such deviations can strongly influence the properties of the resulting powders.

A representative example is the Ni–Al alloy system, which serves as the precursor material for Raney nickel cathodes used in alkaline water electrolysis. Since the electrochemical performance of Raney nickel strongly depends on its chemical composition, accurate control of the alloying elements throughout the manufacturing process is essential. However, during alloy production and ultrasonic atomization, aluminum depletion may occur due to oxidation and evaporation, leading to deviations from the intended composition.

In this work, the chemical composition of Ni–Al alloys was evaluated after casting and ultrasonic atomization. The results reveal significant aluminum loss during processing, resulting in measurable deviations between the nominal alloy composition and the final powder composition. These findings demonstrate that aluminum depletion must be considered during alloy design and powder production in order to achieve the desired powder composition. The study provides valuable insights into composition control during ultrasonic atomization and supports the development of Ni–Al powders for Raney nickel cathode applications.