Electrical Properties of Ag-C Contact Materials Containing Different Allotropes of Carbon
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Electro-mechanical properties of composite materials for high-current contact applications
We report a detailed study that compares various composite materials (CM): Ag/ZnO, Ag/SnO2, Ag/C, Ag/WC, Ag/WC–C and Ag/Ni used in high-current dc circuit breaker applications. Their structural, mechanical, electrical and wetting properties were investigated. In parallel, switching operation tests on the same compounds were performed on commercial high-speed circuit breakers under real conditions (30 kA–900 V). A correlation between the microscopic variables and switching performances of the CMs was established. Materials like Ag/WC and Ag/WC–C were found to be unsuitable for the reliable functionality of the device. In contrast, Ag/C and Ag/SnO2 materials with high electrical and high thermal conductivity revealed remarkably good behaviour during switching operation tests.
A New Vacuum Pressure Infiltration CFRP Method and Preparation Experimental Study of Composite
In order to prepare a carbon-fiber-reinforced polymer composite (CFRP) with ideal microstructure and properties, a new vacuum pressure infiltration CFRP method is proposed based on an analysis of existing CFRP preparation process methods. Research on composite material preparation systems was carried out by using this new method principle. The system mainly includes a fiber pre-forming module, a vacuum heating infiltration module, a hot-press curing molding module, and a data acquisition control module. Under the conditions of natural curing at 0 MPa + 6 h + 25 °C, vacuum heating curing at –0.05 MPa + 30 min + 80 °C, and hot-press curing at 0.7 MPa + 5 min + 50 °C, a two-dimensional (2D) CFRP with excellent microstructure and properties was successfully prepared. Observing the microstructure of the prepared composite material, it can be found that the inside of the composite material was sufficiently and uniformly infiltrated, and common preparation defects such as holes and delamination were effectively controlled. Through the performance test, the bending strength of the material reached 790 MPa.