Abstract:The sound impedance of C/ SiC composite is measured by the method of ultrasonic immersing pulse
echo,and which is between 4. 0×10 6 kg/ m 2 s and 4. 7×10 6 kg/ m 2 s. The relationship of reflection is about 1 when there
is crack in brazing interface and it is between 0. 71 and 0. 74 when there is no crack. For the differential value of the
amplitude of reflection wave is at least 6 dB between two status, the amplitude of more than second reflection wave
will be monitored when C-scan. The result of C-scan is certified by metallographic analysis, and the uniformity of both
is good.