Effect of Mn Doping on the Microstructure and Electrical Properties of Potassium Niobate Ceramics Using Plasma Spraying

Abstract

KNN piezoelectric ceramics are of great importance in the field of scientific research due to their high Curie temperature, good electrical properties, etc. The application of potassium sodium niobate K0.5Na0.5NbO3 (KNN) is strictly limited due to the volatility of Na+ and K+ in KNN and its leakage current. In order to investigate the effect of Mn doping on KNN-based piezoelectric ceramic coatings, KNN and KNN-0.02Mn (KNMN) coatings were successfully prepared using a plasma spraying technique. The phase structure, microscopic morphology, and electrical properties of the coatings were studied in the research. The results showed that both the KNN and KNMN coatings had chalcogenide structures. The KNN coating had an orthogonal phase structure, whereas the KNMN coating had a tetragonal phase structure. Compared with the KNN coating, the microhardness of the KNMN coating was improved through doping with Mn ions. The doping of Mn ions could replace both the A and B sites in the KNN piezoelectric ceramics, further reducing the oxygen vacancies and leakage currents in the coating, and its dielectric properties were improved.