By applying 2205 duplex stainless steel powders to repair and improve carbon steel, multi-pass laser-cladding tests were conducted on Q235 carbon steel surfaces with different laser powers in the range of 1.9~2.5 kW in order to evaluate the performance of the laser-cladding layers. The phase composition, macro- and microstructure, electrochemical corrosion resistance, friction, and wear resistance of the laser-cladding layers were investigated. Macroscopic observation identified no obvious cracks. The phases that made up the multi-pass laser-cladding layers were γ-Fe and α-Fe. Owing to the optimal laser power at 2.3 kW, a large number of equiaxed crystals and a small number of cellular crystals made up the microstructure of the prepared laser-cladding layer, which contributed to its good corrosion resistance. The wear resistance of the multi-pass laser-cladding layer and the carbon steel was also studied. A combined action of adhesive wear and abrasive wear, accompanied by oxidative wear, was determined through observation of pits and furrows on the friction surface of the multi-pass laser-cladding layer, while a typical mechanism of abrasive wear was confirmed by checking the friction surface of the carbon steel.

IrO_x electrodes were fabricated by cyclic thermal heating and water quenching (CHQ) process and high temperature carbonate oxidation (HCO), respectively. By examining the E-pH relationship, response rate, potential drift behavior of the fabricated electrodes, the electrodes prepared by CHQ process seemed to show better comprehensive performance. Characterization tests such as scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and electrochemical impedance spectroscopy (EIS) were used to characterize the fabricated IrO_x electrodes and find out the reason for the better performance of the electrodes prepared by CHQ process. Morphology tests indicate that the CHQ electrode shows a multi-layer structure with more ion channels, which could provide larger surface area for the H⁺ response process. Furthermore, combining the XPS, Raman and EIS tests etc., more effective response composition, better crystal quality, and smaller response reaction resistance of surface IrO_x film could account for the better performance of the CHQ-fabricated IrO_x electrode. The film formation process, H⁺ response mechanism, as well as the response behavior difference between the two kinds of the electrodes are further elaborated.