32.
Laminated Si
3N
4/SiC
w ceramics were successfully prepared by tape casting and hot-pressing. Its mechanical properties were measured and the impact resistance was discussed. The toughness of the laminated Si
3N
4/SiC
w ceramics was 13.5 MPa m
1/2, which was almost 1.6 times that of Si
3N
4/SiC
w composite ceramics, namely 8.5 MPa m
1/2. Moreover, the indentation strength of laminated Si
3N
4/SiC
w ceramics was not sensitive to increasing indentation loads and exhibited a rising R-curve behaviour, indicating that the laminated Si
3N
4/SiC
w ceramics had excellent impact resistance. The improved toughness and impact resistance of laminated Si
3N
4/SiC
w ceramics was attributed to the residual stress caused by a thermal expansion coefficient mismatch between the different layers, resulting in crack deflection and bridging of SiC whiskers in the interface layer, thus consuming a large amount of fracture work.
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