Characterization of crack self-healing of silicon carbide by hot press sintering

본 연구에서는 열간가압소결법으로 SiC를 소결하여 균열자기치유 특성을 분석하였다. SiC는 Al₂O₃ 와 Y₂O₃ 를 소결조제로 1950∘C , 50 MPa, 아르곤(Ar) 분위기에서 소결하였다. 소결된 시편을 3×4×40mm , 절단 및 가공하고, Vickers 경도기를 이용하여 49.6 N으로 예비균열을 생성하였다. 1200~1400∘C , 1~10시간 산화분위기에서 열처리한 후 XRD, SEM, 3점 굽힘강도를 측정하였다. 1300∘C 1시간에서 741 MPa, 5시간에서 770 MPa로 가장 우수한 균열자기치유 효과를 나타내는 것으로 분석되었다. In this study, it was investigated that characteristic of crack-self-healing of hot-pressed SiC. SiC ceramics was sintered with Al₂O₃ and Y₂O₃ sintering additive by hot press. Sintering was performed in hot-press furnace in flowing argon (Ar), holding for 3 hr under 1950∘C and 50 MPa. The sintered SiC was machined into 3-point bending strength specimen of 3×4×40mm , and introduced pre-crack by Vickers indentation at 49.6 N. Specimens were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), 3-point bending strength after heat treatment at 1200~1400∘C for 1~10 hr. The best crack-self-healing ability was achieved 770 MPa 3-point bending strength by heat treatment at 1300∘C for 5 hr.