Dense KSr2Nb5O15 ceramics with uniform grain size prepared by molten salt synthesis

• Published in: Journal of alloys and compounds Vol. 616; pp. 293 - 299
• Main Authors: Liu, Liangliang, Gao, Feng, Zhang, Yong, Sun, Huajun
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.12.2014; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Grain size; KSr2Nb5O15; Lead-free ceramics; Molten salt synthesis; Physics; Grain size; Lead-free ceramics; Molten salt synthesis; KSr2Nb5O15; Potassium Strontium Niobates Mixed; Densification; Grain growth; Presintering; Dielectric properties; KSr; Grain size distribution; O; Nb; Sintering; Lead free ceramics; Property structure relationship; Microstructure; Melts
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2014.07.155

•Dense KSr2Nb5O15 (KSN) ceramics with uniform grain size were synthesized.•Fine KSN needles were used as raw materials.•Using of KSN needles promoted densification due to formation of low energy boundaries.•The Curie temperature and dielectric constant were dependent on the microstructure. Dense KSr2Nb5O15 (KSN) ceramics with various grain-size distributions were prepared by the conventional solid-state sintering under different conditions, e.g. one-step and two-step techniques. Bi2O3 (2mol%) was added as sintering aid. KSN powder crystals prepared by the molten salt synthesis was used as raw materials. Varying temperature from 1250°C to 1350°C at one-step sintering technique were found to enhance abnormal grain growth. For two-step sintering technique, presintering at 1250°C followed by higher sintering temperature of 1350°C controlled abnormal grain growth and obtained a dense KSN ceramics with uniform grain size (an average grain size of 3μm). The effect of KSN powder crystals on promoting densification and presintering technology on controlling abnormal grain growth were discussed. The correlation of microstructure with dielectric properties was investigated.