Aerosol Jet Printing and Low-Temperature Sintering of Magnetostrictive Terfenol-D Nanoparticle Ink

Guided-wave structural health monitoring (SHM) enables continuous, autonomous monitoring of nuclear reactor structures, transitioning maintenance from scheduled to condition-based strategies, thereby reducing the operation costs of nuclear reactors. However, existing SHM systems that typically use electromagnetic or piezoceramic ultrasonic transducers (UTs) often suffer from low signal-to-noise ratios, complex installations, and performance degradation in harsh conditions. Magnetostrictive materials, which deform under magnetic fields and exhibit magnetization variations under mechanical stress, offer the potential for innovative UTs. Nevertheless, deploying magnetostrictive UTs in nuclear reactors poses challenges, primarily due to the cumbersome installations that require either bulky mechanical clamps or deteriorative adhesives. This study employs an aerosol jet printing system to directly deposit magnetostrictive terbium-iron-dysprosium (Terfenol-D) nanoparticles onto metallic structures. Unprecedented Terfenol-D nanoparticles are synthesized using high-energy ball milling. Polyvinylpyrrolidone is utilized as a capping agent, while dimethylformamide and ethylene glycol create a co-solvent system, formulating Terfenol-D nanoparticle colloid inks suitable for aerosol jet printing. Terfenol-D thin discs are printed and sintered using pulsed light at room temperature. Printed Terfenol-D thin films can potentially enhance damage prognosis capabilities, reduce operational costs, and improve safety in existing light-water reactors. This innovative technology applies to various nuclear reactor structures, including piping systems, heat exchangers, and reactor pressure vessels. Its versatility extends to advanced reactor designs, such as sodium or salt-cooled and high-temperature gas reactors.