Toward High-Performance Piezoresistive Polymer Derived SiOC Ceramics through Masked Stereolithography 3D Printing with -Silicon Carbide Nanopowder Reinforcement

Enhancing the piezoresistivity of polymer-derived silicon oxycarbide ceramics (SiOCPDC) is of great interest in the advancement of highly sensitive pressure/load sensor technology for use in harsh and extreme working conditions. However, a facile, low cost, and scalable approach to fabricate highly piezoresistive SiOCPDC below 1400 degrees C still remains a great challenge. Here, the fabrication and enhancement of piezoresistive properties of SiOCPDC reinforced with beta-SiC nanopowders (SiCNP) through masked stereolithography-based 3D-printing and subsequent pyrolysis at 1100 degrees C are demonstrated. The presence of free carbon in SiCNP augments high piezoresistivity in the fabricated SiCNP-SiOCPDC composites even at lower pyrolysis temperatures. A gauge factor (GF) in the range of 4385-5630 and 6129-8987 with 0.25 and 0.50 wt% of SiCNP, respectively is demonstrated, for an applied pressure range of 0.5-5 MPa at ambient working conditions. The reported GF is significantly higher compared to those of any existing SiOCPDC materials. This rapid and facile fabrication route with significantly enhanced piezoresistive properties makes the 3D-printed SiCNP-SiOCPDC composite a promising high-performance material for the detection of pressure/load in demanding applications. Also, the overall robustness in mechanical properties and load-bearing capability ensures its long-term stability and makes it suitable for challenging and severe environment applications.