Joining YSZ electrolyte to AISI 441 interconnect for solid oxide cells using the Ag interlayer: Enhanced mechanical and aging properties

Conventional Ag-CuO braze can lead to two electrolyte/interconnect joining issues: over-oxidation at the steel interconnect and hydrogen-induced decomposition of CuO. This work demonstrates that a pure Ag interlayer, instead of Ag-CuO braze, can join YSZ electrolyte to AISI 441 interconnect in air. Reliable joining between YSZ and AISI 441 can be realized at 920 °C. A dense and thin oxide layer (~2 μm) is formed at the AISI 441 interface. Also, an interatomic joining at the YSZ/Ag interface is detected by TEM observation. Obtained joints display high shear strengths (~86.1 MPa), 161% higher than that of joints brazed by Ag-CuO braze (~33 MPa). After aging in reducing and oxidizing atmospheres (800 °C/300 h), joints remain tight and dense, indicating a better aging performance. This technique eliminates the CuO-induced issues, which will extend lifetimes for SOFC/SOEC stacks and other ceramic/metal joining applications.

Surface Wettability Tuning of Acrylic Resin Photoresist and Its Aging Performance

Photoresist is the key material in the fabrication of micropatterns or microstructures. Tuning the surface wettability of photoresist film is a critical consideration in its application of microfluidics. In this work, the surface wettability tuning of acrylic resin photoresist by oxygen plasma or ultra-violet/ozone, and its aging performance in different atmospheres, were systematically studied. The chemical and physical characterizations of the surfaces before and after modification show a dramatic decrease in the C–C group and increase in surface roughness for oxygen plasma treatment, while a decrease of the C–C group was found for the UV/ozone treatment. The above difference in the surface tuning mechanism may explain the stronger hydrophilic modification effect of oxygen plasma. In addition, we found an obvious fading of the wettability tuning effect with an environment-related aging speed, which can also be featured by the decrease of the C–C group. This study demonstrates the dominated chemical and physical changes during surface wettability tuning and its aging process, and provides basis for surface tuning and the applications in microfluidics.

Research on Aging Performance of AH-90 and PG70-28SBS Modified Asphalt

This paper studied the aging effect of the rolling thin film oven test (RTFOT) , pressurized aging vessel (PAV) and natural ultraviolet radiation aging method on AH-90 and PG70-28 asphalts. penetration degree , penetration degree index,softening point and ductility tests were used to evaluate the high temperature stability, low temperature split and temperature susceptibility of the two aged asphalts , it is pointed that the aging damaged the low temperature performance of the asphalts, improved the high temperature stability and the temperature susceptibility of the asphalts. Compared with the AH-90 asphalt, PG70-28 modified asphalt has better aging performance. The antiaging property and temperature susceptibility of two asphalts after ultraviolet photooxidation and thermal oxidation , were investigated by testing their viscosity index , antiaging index. which indicated that the viscosity index is correlative nearly with the penetration degree index and the influence of 10.5 kJ·cm-2 ultraviolet photooxidation on asphalt performance is more serious than PAV thermal oxidation. The results indicate that ultraviolet photooxidation research on asphalt is necessary in the intensive ultraviolet radiation region of Neimeng.