Papers by Keyword: Functional Composites

Abstract: Careful consideration of friction and wear could save the U.S. economy as much as $120 billion per year. Friction, wear, and lubrication have direct influence on the performance, reliability, and service life of a device that contains moving components. These components are found in applications of energy conversion, power generation, energy harvesting in the broader fields such as agriculture, transportation, and bioengineering etc. The useful life of these systems and their energy efficiency can further be improved by improving the surface performances of sliding systems. Ceramics matrix multifunctional composite due to their unique properties are one of the alternatives for these applications. We report development of alumina based ceramic matrix composites (CMCs) with in-situ functional phases. The overview of properties will be provided. The mechanism for low friction will be discussed. In this investigation, the reinforcement (boron) addition showed strong influence on the in-situ phase formation and surface performance. The phase characterization confirmed formation of AlB₂, B₂O₃, and Al₁₈B₄O₃₃. The sintering temperature showed influence on the stability of these phases. The mixed mode failure was evident from the wear tests. It was found that the coefficient of friction was reduced up to 30% when compared to parent alumina. These newly designed multifunctional composites potential candidate materials that improve the energy efficiency and sustainability.

Abstract: Recently work shown that an imperfection interface can be deduced by a fast sintering, which termed as Self-propagating High-temperature Synthesis plus Quick Pressing (SHS/QP). In order to investigate the effect of imperfection interface on the transport properties of function ceramics, the SHS/QP was applied to fabricate permittivity BaTiO₃ in this article. It was found that this ultra-fast sintering method could not only lead to a broaden-amorphous grain boundary but also semi-conductive grain body simultaneously. It is interesting that the new rapid route can result in the giant permittivity of BaTiO₃.

Abstract: Chitosan (CTS) and Ag-loading nano-SiO2 (SLS) are excellent antibacterial materials. However, when used alone, these monocomponent antibacterial agents are sometimes far from meeting requirements in special conditions. In this study, crosslinked chitosan-coated Ag-loading nano-SiO2 composites (CCTS-SLS) were synthesized by adsorption crosslinking reaction. Then Escherichia coil (ATCC 8099) was taken as the experimental bacteria for antibacterial tests. The experimental results indicate that the mass ratio of SLS to chitosan had the greatest influences on the value of MIC (minimal inhibitory concentration) for CCTS-SLS composite. However, the heating temperature had a weak influence on the antibacterial performance of CCTS-SLS composite.