Synthesis of calcium chloroborate whiskers via sedimentation and sintering process

Abstract

Single crystalline calcium chloroborate (Ca₂B₅O₉Cl) whiskers with uniform diameter have been fabricated by a two-step process. The precursor was firstly prepared by the sedimentation reaction between CaCl₂, H₃BO₃ and NaOH aqueous solutions, and then sintered at different temperatures for 6 h with KCl as flux. The XRD indicates that the product synthesized at 600 °C is Orthorhombic Ca₂B₅O₉Cl. SEM and TEM results show that the Ca₂B₅O₉Cl is whisker with the diameter about 0.2–0.5 μm and the length up to 15 μm. SAED analysis shows that the whisker is single crystalline and grows along [001] direction. The possible formation process and growth mechanism were proposed.

Keywords

single crystal growth / Ca₂B₅O₉Cl / whiskers / microstructures

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