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Poor corrosion and wear resistance of magnesium (Mg) alloys restrict their applications. Herein, corrosion and wear‐resistant films are formed upon Mg alloy AZ31 through a micro‐arc oxidation (MAO) process in silicate electrolyte in the presence of carbon spheres (CS). Surface morphology, chemical composition, corrosion resistance, hardness, and coefficient of friction (CoF) of the MAO coatings are investigated using field‐emission scanning electron microscopy (FE‐SEM), Fourier transform infrared spectrometry (FTIR), X‐ray diffractometer (XRD), X‐ray photoelectron spectroscopy (XPS), electrochemical and hydrogen evolution measurements, automatic micro‐hardness testing, and reciprocating tribometer, respectively. Results demonstrate that the surface morphology and hardness of MAO coatings vary with the concentration of CS. The presence of CS results in an increased coating thickness from 8.0 ± 1.8 to 12.2 ± 1.8 μm, mean pore size from 0.7 ± 0.1 to 1.9 ± 0.1 μm, open porosity of MAO coating from 4.2 ± 0.4 to 5.6% ± 1.1%, and coating hardness from 347.0 ± 59.0 to 853.0 ± 67.3 Vickers‐hardness (HV). Furthermore, CS‐modified MAO coatings lead to improved corrosion resistance in comparison with that of the neat MAO counterparts. Moreover, the high hardness and formation of SiC of CS‐modified coatings lead to a low and stabilized CoF, which implies an enhanced wear resistance.

Y2Ce2O7 ceramic material was prepared by solid reaction at 1600°C for 10h. The phase composition, microstructure and thermal conductivity of this material were investigated. XRD results reveals that single phase Y2Ce2O7 with fluorite structure was synthesized. Microstructure of Y2Ce2O7 was dense and no other unreacted oxides or interphase existed in the interfaces between grains. Because of phonon scattering by oxygen vacancies and difference in atomic mass between substitutional atoms and host atoms, thermal conductivty of Y2Ce2O7 is lower than that of 8YSZ, which implies that this ceramic can be used as novel candidate materials for thermal barrier coatings in the future.

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