Papers by Keyword: Adhesion Layer

Abstract: Sandwich construction is a composite material structure combining low weight, high strength and good dynamic properties. Typically a sandwich composite consists of three main parts: two thin, stiff and strong facing layers separated by a thick, light and weaker inner core. The faces are adhesively bonded to the core to obtain a load transfer between the components. By this way the properties of each separate component is utilized to the structural advantage of the whole assembly leading to a very high stiffness-to-weight and high bending strength-to-weight ratio. As a result sandwich components achieve the same structural performance as conventional materials with less weight. The material characterization described in the paper is aimed at the structural design of the end cub for a high speed train made of composite sandwich materials. A sandwich structure was considered, made of glass fibber polyester face sheets with a polymeric foam core. Initially, the material properties and the rate sensitivity of the skin and core materials were investigated through a series of static and quasi-static tests. Static and dynamic impact tests were then run on the sandwich structure. For all materials tested, no significant strain-rate effects were observed over the range of test conditions investigated in the study. Results show that the structural response of the sandwich depends primarily on the strength properties of the foam core material. Sandwich peel test is intended for determining the comparative peel resistance of adhesive bonds between facing and cores of sandwich constructions tested under specified test conditions. One method, the climbing drum peel method, is most applicable when the peeled facings are relatively thin, but it can not be applicable in tested composite structures. Peel resistance was tested by modified experimental setup.

Abstract: Y₂O₃/YO_x composite coatings with different YO_x adhesion layers were fabricated on 316L stainless steel substrates through reactive magnetron sputtering. The YO_x adhesion layers were deposited by radio frequency reactive magnetron sputtering with different oxygen partial pressures at a total pressure of 1.2 Pa. The Y₂O₃ coatings were deposited by bipolar pulse reactive magnetron sputtering. The relationships between the microstructures, phase compositions, interfacial adhesion of the composite coatings and the oxygen partial pressure used for deposition of the YO_x adhesion layers were investigated. The microstructures and phase compositions of the coatings were characterized by scanning electronic microscopy and X-ray diffraction. The bonding strength of the coatings was measured by scratch tester. The results showed that the bonding strength of the Y₂O₃/YO_x composite coatings reached the maximum value when the oxygen partial pressure was 0.18 Pa.