Abstract: A method for producing polygonic Zn oxide platelets having a median specific surface area of more than 25 square meters per gram, in controlled size and morphology, the method comprising: preparing a medium including Zn or its compounds at a concentration within the range between 1.55 and 7.75 moles of Zn/L, in a medium suitable to substitute Zn ions by releasing free protons thereby forming a complex structure including Zn; agitation of the medium in a vessel at a temperature within the range between 50 and 320° for a duration up to 10 hours to obtain a suspension; filtering the suspension to obtain a filtrate including solid particles; drying and then calcination of the dried filtrate; wherein the agitation is performed with one or more radial flow impellers so that the Reynolds' number in the vessel is higher than 2500 and lower than 10000.

Abstract: A lead-free KNN-based piezoelectric material represented by the composition formula (KaNabLic)(NbdTaeSbf)Og, where 0.4?a?0.5, 0.5?b?0.6, 0.01?c?0.1, 0.5?d?1.0, 0.05?e?0.15, 0.01?f?0.09, 1?g?3. In one embodiment, the lead-free KNN-based piezoelectric material has a d33>300 pm/V and a Tcurie>250° C. In one embodiment, the d33 and Tcurie of the lead-free textured KNN-based piezoelectric material can be adjusted by creating phase boundaries of (i) orthorhombic to tetragonal (O-T), (ii) rhombohedral to orthorhombic (R-O), and (iii) orthorhombic to tetragonal (O-T). In one embodiment, the lead-free KNN-based piezoelectric material is textured with NaNbO3 or Ba2NaNb5O15 seeds which are platelet or acicular shaped. In one embodiment, the amount, orientation, or particle size distribution of the NaNbO3 or Ba2NaNb5O15 texturing seeds in the lead-free textured KNN-based piezoelectric material can be altered.

Abstract: A method for producing polygonic Zn oxide platelets having a median specific surface area of more than 25 square meters per gram, in controlled size and morphology, the method comprising: preparing a medium including Zn or its compounds at a concentration within the range between 1.55 and 7.75 moles of Zn/L, in a medium suitable to substitute Zn ions by releasing free protons thereby forming a complex structure including Zn; agitation of the medium in a vessel at a temperature within the range between 50 and 320° for a duration up to 10 hours to obtain a suspension; filtering the suspension to obtain a filtrate including solid particles; drying and then calcination of the dried filtrate; wherein the agitation is performed with one or more radial flow impellers so that the Reynolds' number in the vessel is higher than 2500 and lower than 10000.

Abstract: The process incorporating the invention enables fabrication of dense, highly textured (fraction of oriented grains >20 vol. %) alumina. The method uses a mixture of aluminum metal powder, alumina powder, tabular alumina grains and a liquid phase former. A dry powder mixtures of these components is compacted by dry forming techniques such as roll compaction, uniaxial pressing, forging and/or double action pressing. The formed part is then heated at 0.5-10° C./min. to a temperature between 450 and 500° C. and is held for 2-15 h, and is then heated at 1-10° C/min. to 900-1070° C. and is held for 2-10 hours to convert the aluminum particles into alumina. The part is then heated to a higher temperature (>1400° C.) to form a liquid phase which assists densification and promotes the growth of the tabular alumina grains. The aspect ratio range of the textured alumina grains is from 2-14.