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This study investigated the influence of codoping with Ge and GeO2 on the nonlinear coefficient α and the breakdown voltage EB of TiO2–Nb2O5–SrCO3 varistor ceramics. Ge–GeO2 codoping notably changed the microstructure of the TiO2–Nb2O5–SrCO3 ceramics, increased α, and decreased EB. When the doping contents of Nb2O5 and SrCO3 were 0.1 and 0.2 mol%, respectively, the optimum doping content of 0.25 mol% Ge and 0.75 mol% GeO2 exhibited high α (11.6), low EB (13.8 V/mm), and high grain‐boundary barrier ΦB (0.96 eV). These results are superior to previous findings. In addition, Ge and GeO2, which function as sintering aids, reduced the sintering temperature caused by the low melting point. The optimal sintering temperature was 1260°C for the TiO2–Nb2O5–SrCO3 ceramics doped with Ge and GeO2.

This objective is to study the influence of pH on the electrochemical behavior of 00Cr15Ni7Mo2Cu2 supermartensitic stainless steel in 3.5% NaCl solutions using potentiondynamic polarization technique, open circuit potential tests and electrochemical impedance spectroscopy (EIS).The study reveals that the pitting potential (Eb) is higher, the passivation current densities (ip) is lower and the electrochemical impedance increases with the pH. The results indicate that this stainless steel offer good pitting corrosion resistance with the pH increasing in 3.5% NaCl solutions.