1992 年 58 巻 1 号 p. 99-104
This paper describes the fracture mechanism and the prevention of crack propagation in laser-processing of the hot-pressed silicon nitride ceramics using the pulsed YAG laser. The crack formation mechanism is successfully explained by the thermal stress and fracture strength distribution. The laser pulses controlled at below the critical duration and frequency are effective for the purpose of crack-free processing because the thermal stress is localized only in the laser-heated shallow region.