Al₃BC₃ Powder: Processing and Synthetic Mechanism

Abstract

The processing parameters for the synthesis of Al3BC3 powder were optimized, and the synthetic mechanism was investigated. The mechanical mixing of the raw powders promoted the formation of secondary phases due to mechanical alloying effect and contamination. Nearly X‐ray pure Al3BC3 powder was obtained after the calcination of the raw powder mixture at 1800°C for 2 h in Ar by suppressing the vaporization of aluminum. During calcination, Al4C3 layer was formed at the surface of aluminum powder by the reaction with carbon, which maintained the morphology of the aluminum powder above its melting temperature. The nucleation and growth of Al3BC3 within aluminum melt began to occur at 1000°C, and became the main synthetic mechanism of Al3BC3 at 1100°C. The Al3BC3 particles synthesized at 1100°C were porous and were composed of fine hexagonal crystals. The main synthetic mechanism of A3BC3 changed into solid–solid reaction above 1100°C, and a gas–solid reaction promoted the densification of the porous Al3BC3 powder above 1340°C.

Synthesis of a Fine (Ta0.8,Hf0.2)C Powder from Carbide or Oxide Powder Mixtures

“…The average grain sizes of the synthesized (Ti,W)C powders were >100 nm and 10.4–28.3 nm when using the oxide and carbide raw materials, respectively. Lee et al also reported the growth of Al 3 BC 3 particles up to 20 μm when prepared using Al(OH) 3 ‐B 2 O 3 ‐C as the starting materials while the average particle size was 14.1 μm using Al, B 4 C and C as raw materials . Although several reports indicated that the growth of ternary carbides occurred more strongly during synthesis when using the oxide raw materials than carbides, the reasons have not been clearly identified.…”

PHASE FORMATION DURING THE COMPOSITE B4C‒SiC‒ Si(Al) Reactive Sintering

“…Однако в реальных условиях реакционное спекание при температурах ниже 1100 °С практически невозможно вследствие высокого значения угла смачивания B 4 C расплавом Al. В связи с этим пропитку проводят при ~1200 °C, что обуславливает появление в составе конечного материала как низкотемпературных, так и более тугоплавких фаз, в том числе образовавшихся при взаимодействии продуктов реакций (5)-(9) между собой [37]:…”

Synthesis of Monophasic Al3BC3 Powder with Hexagonal Plate-like Morphology

“…Since then, many researchers have investigated the synthetic mechanism. It has been reported that the addition of excess B 4 C is required to synthesize monophasic ABC due to vaporization of boron during the heating process. , In other cases, Lee et al demonstrated a nearly phase-pure ABC powder synthesized by using a carbon crucible and cap with BN paste to suppress the vaporization of aluminum. , A technique for the synthesis of monolithic ABC by reactive hot-pressing was also reported, but it is necessary to separate the calcination and hot-pressing stages . Many researchers have synthesized ABC by a variety of preparation techniques; however, the processes are complex and cumbersome, and the synthetic mechanism has not yet been clarified in detail. − Therefore, the development of a scalable, simple, and low-cost synthesis process for pure ABC powder is clearly needed for industrial applications.…”

“…11,12 In other cases, Lee et al demonstrated a nearly phase-pure ABC powder synthesized by using a carbon crucible and cap with BN paste to suppress the vaporization of aluminum. 7,13 A technique for the synthesis of monolithic ABC by reactive hot-pressing was also reported, but it is necessary to separate the calcination and hot-pressing stages. 14 Many researchers have synthesized ABC by a variety of preparation techniques; however, the processes are complex and cumbersome, and the synthetic mechanism has not yet been clarified in detail.…”