A TiC-Mo 2C-WC-Ni alloy cermet was fabricated by high-energy ball milling (HEBM) and consolidation through spark plasma sintering. The TiC-based powders were synthesized with different milling times (6, 12, 24, and 48 h) and subsequently consolidated by rapid sintering at 1300°C and a load of 60 MPa. An increase in the HEBM time led to improved sinterability as there was a sufficient driving force between the particles during densification. Core-rim structures such as (Ti, W)C and (Ti, Mo)C (rim) were formed by Ostwald ripening while inhibiting the coarsening of the TiC (core) grains. The TiC grains became refined (2.57 to 0.47 µm), with evenly distributed rims. This led to improved fracture toughness (11.1 to 14.8 MPa·m 1/2) owing to crack deflection, and the crack propagation resistance was enhanced by mitigating intergranular fractures around the TiC core.

Al-Cu thin films were fabricated by RF magnetron sputtering from aluminum (Al) and copper (Cu) metal targets to improve the acoustic performance of SAW devices on LiNbO₃ substrates. To optimize the electrode material for SAW devices, Al-Cu films with various compositions were fabricated and their electrical, mechanical, and acoustic properties were comprehensively evaluated. The Al-Cu films exhibited a gradual decrease in resistivity with increasing Al content. The double-electrode SAW devices composed of Al-Cu films demonstrated a resonant frequency of 70 MHz and an average insertion loss of −16.1 dB, which was significantly lower than that of devices made with traditional Au or Al electrodes. Additionally, the SAW devices showed an increase in the FWHM values of the resonant frequency and a decrease in the insertion loss as the Al content in the IDT electrode decreased. These findings indicate that improving the performance of SAW devices can be achieved by reducing the density of the IDT electrodes, rather than focusing solely on their electrical characteristics.

The development of efficient photoelectrode materials for solar water splitting is often hindered by time-consuming and costly compositional optimization. To address this challenge, we fabricated a molybdenum (Mo)-doped bismuth vanadate (BiVO4) thin-film library with a wide compositional gradient on a single substrate using a combinatorial sputtering system. The photoelectrochemical (PEC) properties of this library were then rapidly evaluated using a custom-built high-throughput scanning photoelectrochemical microscopy (SPECM) system. Analyses of the composition, structure, morphology, and optical properties revealed that Mo concentration critically influences the film's crystallinity and PEC activity. Excessive Mo doping led to lattice distortion and microstructural defects, which enhanced charge recombination and decreased photocurrent. Conversely, a low Mo concentration in the range of 1–2 at.% achieved an optimal balance, preventing the charge recombination via n-type doping while preserving the excellent crystallinity of the BiVO4 lattice. Consequently, the highest photocurrent (0.15 mA/cm2) was observed for BVO4 films with 0.96 at.% Mo. This study demonstrates that the integration of combinatorial synthesis with high-throughput screening provides a powerful and efficient strategy for rapidly identifying optimal photoelectrode compositions and systematically elucidating the interrelationship among their properties.

Cu-Ti thin films were fabricated using a combinatorial sputtering system to realize highly sensitive surface acoustic wave (SAW) devices. The Cu-Ti sample library was grown with various chemical compositions and electrical resistivity, providing important information for selecting the most suitable materials for SAW devices. Considering that acoustic waves generated from piezoelectric materials are significantly affected by the resistivity and density of interdigital transducer (IDT) electrodes, three types of Cu-Ti thin films with different Cu contents were fabricated. The thickness of the Cu-Ti thin films used in the SAW-IDT electrode was fixed at 150 nm. As the Cu content of the Cu-Ti films was increased from 31.2 to 71.3 at%, the resistivity decreased from 10.5 to 5.8 × 10-5 ohm-cm, and the density increased from 5.5 to 7.3 g/cm 3 , respectively. A SAW device composed of Cu-Ti IDT electrodes resonated at exactly 143 MHz without frequency shifts, but the full width at half maximum (FWHM) values of the resonant frequency gradually increased as the Cu content increased. This means that although the increase in Cu content in the Cu-Ti thin film helps to improve the electrical properties of the IDT electrode, the increased density of the IDT electrode deteriorates the acoustic performance of SAW devices.