Search Results (3)

The minimum refractive index of the aluminophosphosilicate (APS) core in optical fibers has been determined for a wide range of phosphorous and aluminum concentrations. It was found that the APS core refractive index became higher by ~0.0005–0.0012 as compared to that in optical fiber preform. The analysis of the measured data has shown that at least 0.2 mol.% of Al₂O₃ and P₂O₅ remain in their ordinary form near their equimolar concentrations and do not form an AlPO₄ join (the effect observed for all concentrations of AlPO₄ join from 5 to 25 mol.%). Full article

High-temperature adhesives find extensive application in diverse domains, encompassing repairs, production processes, and material joining. However, achieving their curing at ambient temperatures remains a formidable challenge due to the inherent requirement of elevated temperatures, typically exceeding 500 °C, for the curing reaction. To overcome this limitation, in this study, we developed a distinctive inorganic phosphate-based composite adhesive by incorporating dual-functional calcium monoaluminate (CA) into a traditional adhesive blend comprising Al(H₂PO₄)₃ and MgO. This distinctive approach significantly diminishes the curing temperature, enabling it to occur at room temperature. Firstly, CA’s facile hydration reaction effectively scavenges surrounding water molecules, thereby accelerating the dehydration curing process of Al(H₂PO₄)₃. Secondly, as hydration is an exothermic process, it locally generates heat around the Al(H₂PO₄)₃, fostering optimal conditions for its curing reaction. Moreover, the adhesive’s strength is substantially bolstered through the strategic inclusion of Nano-Al₂O₃ (enhancing the availability of reaction sites) and Nano-SiO₂ (improving overall stability). As a demonstration, the adhesive formulation with added CA containing 2% Nano-Al₂O₃ and 2% Nano-SiO₂ achieved a remarkable tensile strength of 32.48 MPa at room temperature, underscoring its potential as an efficient solution for various practical adhesive applications. The adhesive prepared in this study harnesses the hydration properties of CA to absorb moisture and release substantial heat, introducing a novel method for ambient temperature curing. This development promises to broaden its applications in refractory materials, coatings, and equipment repair. Full article

Carbon fiber reinforced polymer (CFRP) is widely used in the lightweight design of high-speed trains due to its high specific strength. In order to further reduce the weight of the high-speed train body, it is necessary to study the joining process and fatigue properties of CFRP/aluminum alloys (CFRP/Al) structure. In this work, the CFRP plate and 5083P-O aluminum plate were successfully connected by an induction brazing method. The optimum parameters of induction brazing were determined to be an induction temperature of 290 °C, a normal pressure of 200 kPa, and a holding time of 5 s. After the 5083 plate was pre-anodized, the tensile strength of the CFRP/5083 joint reached a maximum value of 176.5 MPa. The anodization process introduced more surface micro-structures on the 5083 plate, leading to a better wetting behavior between CFRP and oxide film. Meanwhile, a new chemical bond, Al-O-C, was also formed at the interface of the CFRP/5083 joint. The fatigue limit of the CFRP/5083 joint was calculated to be 71.68 MPa through high-cycle fatigue (HCF) testing. The fatigue cracks initiated from the interface of CFRP/oxide film, and then propagated to base metal. Finally, the oxide film was peeled off from the base metal under shear stress, which contributed to the fracture of the CFRP/5083 joint. The bonding strength between CFRP and 5083 aluminum alloy is far from the conventional welded joints. Therefore, feasible approaches should be proposed to obtain a more robust bonding between CFRP and aluminum alloy in the future. Full article