CMAS Corrosion Behavior of Mid-Entropy Rare-Earth Hafnate (YGdYb)HfO as Thermal Barrier Coating Candidate.

High-temperature CMAS corrosion has become a crucial factor inhibiting the further development of thermal barrier coatings (TBCs) because of the increasing service temperature of aero-engines. Herein, a novel mid-entropy rare-earth hafnate (YGdYb)HfO (YGYbH) was prepared by ultrafast high-temperature sintering (UHS) technology, and its CMAS corrosion behavior and mechanism were investigated. During corrosion, the CaRE(SiO)O apatite phase with a lower formation enthalpy and entropy-stabilized effect had a more intense tendency to be generated, which improves the density and stability of the reaction layer, hindering the further penetration of molten CMAS.

A silver catalyst with a high-energy surface prepared by plasma spraying for the hydrogen evolution reaction.

A self-supported silver electrode was prepared by plasma spraying and used for catalysing the hydrogen evolution reaction. Thanks to the non-equilibrium synthetic conditions, the silver catalyst exposes high-energy (200) crystal planes, which enhance the adsorption of hydrogen and improve the intrinsic catalytic activity. As a result, the silver catalyst delivers an overpotential of 349 mV at 10 mA cm, which was much lower than those of Ag foil (742 mV) and commercial Ag powder (657 mV).

Microstructure and Mechanical Properties of an Ultrasonic Spot-Welded Aluminum-to-Aluminum Joint: Response to Interlayer Thickness.

To enhance the mechanical strength of an ultrasonic spot-welded Al/Al joint, an Al 2219 particle interlayer was placed between the two Al sheets during the ultrasonic spot welding process. The effects of the interlayer thickness on the microstructure and mechanical performances of the joints were systematically investigated. The results showed that, the optimum thickness of the Al 2219 particle interlayer was 10 μm, which was beneficial to enhance the weld interface temperature up to 402 °C.