Synthesis of Multilayered Star‐Shaped B₆O Particles Using the Seed‐Mediated Growth Method

Abstract

In this study, we introduce a simple and effective seed-mediated growth method (SMGM) for the controlled synthesis of boron suboxide powder. By employing starting powders with different concentrations and adding boron suboxide seeds with a star-like morphology, we demonstrate that B 6 O ceramics that exhibit high-level crystallinity can be synthesized using SMGM at ambient pressure conditions. The formation of multilayered starshaped B 6 O particles via SMGM is reported for the first time.

High‐Temperature Strength of Boron Suboxide Ceramic Consolidated by Spark Plasma Sintering

“…Black areas in Fig. correspond to the residual amorphous B–O phase resulting from the synthesis of boron suboxide powder . In general, the fracture observed at room temperature is identical to that expected for boron carbide …”

“…Two commercially available powders, amorphous boron (aB, 97%; Wako Pure Chemical Industries, Ltd., Osaka, Japan) and B 2 O 3 powder (99.0%; Kanto Chemical Co., Inc., Tokyo, Japan), were used as the starting materials. The mixing procedure for the B 2 O 3 and aB raw powders was the same as that in our previous works . The raw powders were mixed in 6:1 and 10:1 aB:B 2 O 3 mole ratios (B 6 O‐6:1 and B 6 O‐10:1 ceramics, respectively).…”

“…The raw powders were mixed in 6:1 and 10:1 aB:B 2 O 3 mole ratios (B 6 O‐6:1 and B 6 O‐10:1 ceramics, respectively). 15 wt% presynthesized B 6 O powder seeds with star‐like shape, were added to the mixture during synthesis process . The method for obtaining seeds, and their characterization is presented in Ref.…”

“…Microstructure of B 6 O ceramics: (a) SEM image of initial boron suboxide powder of B 6 O‐10:1 ceramic mass‐synthesized as described in Ref. (b1 and b2) show the room temperature fracture of SPS ed B 6 O‐10:1 ceramic, whereas (c) shows fracture of B 6 O‐10:1 at 1000°C. Circles indicate that small identical porosity is viewed at room temperature and after high‐temperature flexural strength tests.…”

“… indicate that spark plasma sintering (SPS) of boron suboxide powders with a low oxygen deficiency level, that is, high x value in B 6 O x , can be employed as a method for obtaining dense boron suboxide ceramics at ambient pressure. One of the key reasons for this is the use of Ta foil, which prevents carbon diffusion into the B 6 O lattice, allowing the initial low oxygen deficiency level of the as‐synthesized powder to be preserved . Furthermore, as this boron suboxide powder has a low oxygen deficiency level in its B 6 O x cells (i.e., x = 0.88), the hardness of a bulk sample subjected to SPS was reported to be comparable to that of ceramic tiles synthesized at a high pressure .…”