Papers by Keyword: Ball-Milling Process

Abstract: In this work, nano-crystalline Mg2Si powder was prepared by ball milling and structural studies vs ball milling time are presented. The identification of the phases of the materials and the evaluation of their purity were performed using Powder X-ray diffraction (PXRD). Crystallite size evolution during ball milling was followed by PXRD and single line analysis, based on Scherrer equation. Transmission Electron microscopy (TEM) observations and IR Reflectivity measurements were used for the investigation of nano-features and confirmation of the PXRD results.

Abstract: Doping a small quantity of additive Bi2O3 is effective in suppressing the deliquescence of KNbO3 ceramics. When an optimized ball-milling process was included, dense and nondeliquescent KNbO3 ceramics were obtained by a conventional firing process. However, the presence of Bi prevented grain growth (<0.2 μm) and it was one of the causes of low ferroelectricity. Moreover, the insufficient resistivity made the poling treatment difficult. In order to improve the electric properties, a small quantity of additive MnCO3 was also doped into KNbO3 with 0.5 mass% Bi2O3. Codoping of KNbO3 with MnCO3 and Bi2O3 (abbreviated to KNBixMny; x = 0~1.0, y = 0~1.0 in mass%) improved the ferroelectricity of samples, and it also had an effect on the resistivity and densification of sintered bodies. Well-saturated P-E hysteresis loops were observed with any amount of Mn and the largest remanent polarization Pr was about 16 μC/cm2. The piezoelectric properties of KNBi0.5Mn0.3, which had the highest piezoelectricity in this study, are an electromechanical coupling factor k33 and piezoelectric constant d33 of 0.30 and 101 pC/N, respectively.