| Polymer-derived ceramics?PDC?have excellent resistance to high temperatures,oxidation and semiconductivity,and their electronic properties can be easily optimized by changing the carbon content of the PDC structures.PDC ceramics can be used as sensor,lithium ion battery anode material,etc.,which PDC ceramics preparation into temperature sensor is a hot topic in international research.Graphene oxide?GO?was used as the carbon source,Ethyl alcohol?ETOH?as the dispersant,Dicumyl peroxide?DCP?as the thermal initiator,Polyvinylsilazane was used as the precursor of PDC-SiCNO ceramics to the different GO content of PDC-SiCNO-GO ceramics composites.It was found that GO was present in microspheres in the PDC-SiCNO-GO ceramic matrix when the GO content was 0.03 wt%and 0.1 wt%.When the GO content was 0.3 wt%,the GO microspheres were collapsed.Combining with FI-IR and XRD analysis showed that GO microspheres were reacted and recombined through the NH3 released from the hydrolysis of PVSZ.The Raman and EPR characterization showed that the carbon clusters in the ceramic structure increased from 1.26 nm to 1.47 nm with the increase of GO content in the PDC-SiCNO-GO ceramic structure,and the number of unpaired electrons increased with the increase of GO content.Analysis the DC conductivity of PDC-SiCNO-GO ceramic at room temperature found that when the ceramic structure of GO from 0 wt%to 0.1 wt%,the conductivity from 1.62E-08??/cm?-1 increased to 1.39E-07??/cm?-1.And the DC conductivity of PDC-SiCNO-GO ceramics decreases to 6.56E-08???when the wt%of GO in the PDC-SiCNO-GO ceramic structure increases to 0.3 wt%.Analysis the temperature-dependence DC conductivity,dielectric constant at room tempera,temperature-dependence dielectric constant of PDC-SiCNO-GO ceramic,it is found that the temperature-dependence DC conductivity,dielectric constant at room tempera,temperature-dependence dielectric constant first increase and then decrease when GO wt%increase from 0 wt%to 0.3 wt%.Different GO wt%content of graphene reinforced SiCN ceramics?PDC-SiCN-rGO?were prepared by using GO as carbon source,N'N-dimethylformamide?DMF?as dispersant,DCP as thermal initiator and PVSZ as precursor of PDC-SiCN ceramics.The EDS/SEM analysis of the C element in the ceramic structure revealed that when the GO content was 0.3 wt%,the distribution of C elements in the ceramic structure was agglomerated.Combined with Raman mapping,it was found that the size of carbon clusters in the ceramic structure was not uniform when the GO mass fraction was 0.3 wt%.The DC conductivity of PDC-SiCN-rGO was found to be 6 orders of magnitude higher than that of pure SiCN ceramics when PDC-SiCN-rGO ceramic containing 0.2 wt%GO,reaching 4.35E-03??/cm?-1.EDS/SEM and Raman spectroscopy investigated the conductivity of PDC-SiCN-rGO ceramics.It was found that the DC conductivity of PDC-SiCN-rGO ceramics was not only related to the concentration of carbon dangling bonds in the ceramic structure,but also to the "free-carbon" distribution in PDC-SiCN-rGO ceramics structure.The PDC-SiCNO and PDC-SiCNO-GO-0.1 ceramics based temperature sensor was fabricated.It was found that in the testing temperature range of 25-600 ?,PDC-SiCNO and PDC-SiCNO-GO-0.1 ceramic base active temperature sensor B is 1350 K and 2409 K,respectively.The sensitivity of the temperature sensor in the testing temperature ranges are-2.7%K-0.32%K and-1.5%K-0.18%K,respectively,indicating that the PDC-SiCNO-GO-0.1 based temperature sensor is more stability and sensitivity than PDC-SiCNO based temperature sensor.Finally,design a micro temperature measurement system to improve the practicality of the temperature sensor. |
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