Gold authentication is vital across industries due to the metal’s high value and widespread susceptibility to counterfeiting. Conventional testing methods such as fire assay and X-ray fluorescence (XRF), while accurate, often involve destructive procedures, high costs, and complex operational requirements. This study investigates the use of ultrasonic testing as a non-destructive, efficient, and accurate alternative for detecting adulterants in gold. Utilizing COMSOL Multiphysics simulations, the research models the propagation of ultrasonic waves through pure and adulterated gold specimens, including inclusions of tungsten (W), copper (Cu), silver (Ag), acrylic, and air. The simulations analysed wave characteristics such as velocity, attenuation, and acoustic signal amplitude at various frequencies (1 MHz to 20 MHz). Results show that pure gold yields consistent and high acoustic values, while the presence of adulterants significantly alters the acoustic response. High-density materials like tungsten, despite their physical similarity to gold, are effectively identified due to acoustic impedance mismatches. Detection sensitivity improves with higher ultrasonic frequencies, particularly at 10 MHz and 20 MHz. These findings validate the potential of ultrasonic testing as a scalable and non-invasive method for gold authentication, suitable for both industrial quality control and field applications.

COMSOL Multiphysics Simulation, Gold Authentication, Ultrasonic Testing, Non-Destructive Testing (NDT)