Dense growth of multiply-twinned star-shaped molybdenum particles by atmospheric H2/Ar microplasma jet

Abstract

Five-fold symmetrical star-shaped (s-) multiply twinned particles (MTPs) of molybdenum (s-Mo-MTPs) were successfully prepared by atmospheric H₂/Ar microplasma jet. The formation of MTPs in materials whose stable phase is not an fcc structure has been reported in only a few cases with small quantities, and the MTPs have never been prepared in Mo whose stable phase is a body-centered cubic (bcc) structure. In this study, s-Mo-MTPs were formed as the dominant product and densely grown on the substrate. Each s-Mo-MTP grew along a five-fold axis, and the star-shaped cross-section area became larger toward the top. This top-heavy morphology is unique among the morphologies of MTPs reported up to now. Here, we report on a simple method to prepare s-Mo-MTPs using atmospheric H₂/Ar microplasma jet, the details of the morphology and the microstructure, and the growth mechanism discussed based on our observations.