In the laser slicing process of SiC, we investigated the relationship between the laser scanning direction and cleavage extension to determine a scanning method suitable for the crystal structure of SiC. Evaluation of the kerf loss and peeling stress by parallel or vertical laser scanning to the orientation flat showed that parallel scanning suppresses the extension of cleavage along the off angle and reduces kerf loss. Conversely, vertical laser scanning promoted cleavage extension along the off angle and increased kerf loss but decreased peel stress. Thus, there is a trade-off relationship between kerf loss and peeling stress. Based on these results, we devised a rectangular scanning method that enables control of cleavage. The results indicated that cleavages were linearly connected to the [1-100 ]direction, and kerf loss was reduced by 23.9% and peeling stress was reduced by 43.5% compared to the conventional scanning method.

Powder jet deposition (PJD) is a film formation technique involving the high-speed collision of particles on the target material, and it can be performed at room temperature and under atmospheric pressure. These characteristics enable PJD to create a film of hydroxyapatite (HA) on human teeth. However, the film hardly conceals the base color due to its transparency. Therefore, ZrO₂ particles and HA particles covered with ZrO₂ particles were employed in PJD. The film forming effectiveness was higher in the order HA particles, composite particles, and ZrO₂ particles. Conversely, the brightness per film thickness was higher in the reverse order. Comparing the entire film deposited within one operation, the composite film was the brightest, and ZrO₂ layers were evenly distributed within it. These results indicated that PJD could be applied to aesthetic dental treatment.