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A new precursor of liquid and curable polysiloxane for highly cost-efficient SiOC-based composites
摘要： Polymer-derived SiOC matrix composites are very promising structure ceramics in moderate temperature (< 1200 °C) application, in view of their outstanding comprehensive performance and satisfying costs. Herein, we developed a new precursor of liquid and curable polysiloxane (LC-PSO) with Si-H and vinyl side groups to meet the requirements of precursor infiltration and pyrolysis (PIP) route for preparing highly cost-efficient composites. It was found that the crosslink structure was completely built below 150 °C through hydrosilylation reaction, thus converting the liquid precursor into solid state and rendering the cured product with a high ceramic yield of 81.1%. The addition reaction was also greatly inhibited under 5 °C in order that the LC-PSO was able to store for long time. We revealed that although the SiOC ceramic underwent structural rearrangement and slow crystallization during pyrolysis, no mass loss was observed below 1400 °C before the carbothermal reaction was initiated. The prepared carbon fiber-reinforced SiOC (2D-Cf/SiOC) composite verified the feasibility of directly using LC-PSO as precursor for PIP process, and the mean flexure strength and modulus of the composite were 253.3 MPa and 33.3 GPa, respectively. Our work presents the great potential of LC-PSO in fabricating highly cost-efficient CMCs for moderate temperature application.
关键词： CMCs,SiOC matrix,PIP process,Precursor,Polysiloxane
更新于2025-09-23 15:22:29
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Growth of multi-morphology amorphous silicon oxycarbide nanowires during the laser ablation of polymer-derived silicon carbonitride
摘要： Multi-morphology amorphous SiOC nanowires were successfully prepared within the interfacial interstices between the una?ected SiCN ceramic and the bracket during the laser ablation of polymer-derived SiCN ceramic in a low-pressure argon atmosphere. Laser irradiation experiments were performed using a continuous-wave CO2 laser, and the gas source for the growth of amorphous SiOC nanowires was provided by the laser ablation of the SiCN ceramic. X-ray photoelectron spectroscopy shows that the amorphous SiOC nanowires possess a SiO2 dominated nanostructure, and the formation of amorphous SiOC nanowires is attributed to the good di?usivity of CO in SiO2. The morphologies of the amorphous SiOC nanowires include straight nanowires, beaded nanowires, helical nanowires, and branched nanowires, and these are determined by the ?owing state of the reactant gases, the laser power, and the surface morphology of the SiCN ceramics. Each amorphous SiOC nanowire with speci?c morphology can be uniformly distributed in separate regions, which makes it possible to control the growth of amorphous SiOC nanowires in di?erent morphologies.
关键词： Laser ablation,SiOC,Polymer-derived ceramics,Amorphous nanowires,Multi-morphology
更新于2025-09-12 10:27:22
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Relationship Between the Mobility and the Schottky Contact in Indium-Gallium-Zinc-Oxide Thin Film
摘要： This presents the contact mechanism to understand the relationship between the Schottky contact and tunneling phenomenon on in the IGZO (Indium Gallium Zinc Oxide) Thin Film. The tunneling transistors with bi-directional ambipolar transfer characteristics were made by high potential barriers at the Schottky contact related to the depletion layer. The IGZO thin film transistor was prepared on SiOC with various annealing temperatures of 100 °C～400 °C. The performance of TFT was improved at SiOC annealed at 300 °C with the Schottky contact. The IGS curves of TFT with SiOC annealed at 300 °C showed high Ion/Ioff ratio and without the threshold voltage shift, when applied at VDS = 0.0001 V, because of the tunneling phenomenon from the band to band of diffusion currents through deep potential barrier.
关键词： IGZO,Schottky Contact,SiOC,Diffusion Current,Ambipolar Transfer Characteristics
更新于2025-09-04 15:30:14