From Al₄B₂O₉ Nanowires to BN-Coated Al₁₈B₄O₃₃ Nanowires

Abstract

A novel route was proposed to completely coat aluminum borate nanowires by in situ providing the precursor for BN coating. Uniformly BN-coated Al18B4O33 nanowires could be obtained by the reaction of Al4B2O9 nanowires with ammonia at high temperature. The high-temperature unstable Al4B2O9 nanowires were converted into Al18B4O33 nanowires, simultaneously evaporated boron oxide. The reaction between the in situ generated vapors and ammonia ensures that the BN layers are attached tightly on the surface of the as-formed Al18B4O33 nanowires.

Elucidating structural order and disorder phenomena in mullite-type Al4B2O9 by automated electron diffraction tomography

“…In addition, other approaches, such as sol-gel synthesis, one-step combustion method, and thermal evaporation, have been applied to improve the formation and properties [3,7,8]. One of the characteristic properties of mullite-type structures are linear edge-sharing octahedral chains, which are connected parallel to each other by different inter-chain units controlling the growth of nanowires and nanorods [4,9].…”

Effect of different B contents on the mechanical properties and cyclic oxidation behaviour of β-NiAlDy coatings

“…It has been shown by Tao et al the minimum temperature required for the formation of Al 4 B 2 O 9 phase is 780°C [33] and it is a low-temperature stable phase which can exist at the temperatures between 800°C and 1000°C [34,35]. At a higher temperature, Al 4 B 2 O 9 will be converted to Al 18 [36]. Another factor that resulted in scale rumpling is probable that the liquid B 2 O 3 formed during the oxidation at 1200°C would solidify during cooling to ambient temperature.…”

Mechanical and thermal properties of light weight boron‐mullite Al5BO9

“…Up to now, most of the experimental studies focus on the synthesis of Al 5 BO 9 whiskers, which are used for strengthening of aluminum alloys 13 . Methods utilized for the synthesis of phase pure Al 5 BO 9 include solid‐state reaction, 14,15 molten salt, 11 and sol‐gel 16 .…”

“…Up to now, most of the experimental studies focus on the synthesis of Al 5 BO 9 whiskers, which are used for strengthening of aluminum alloys. 13 Methods utilized for the synthesis of phase pure Al 5 BO 9 include solid-state reaction, 14,15 molten salt, 11 and sol-gel. 16 In addition, Gatta et al 17,18 found that no phase transition occurred to Al 5 BO 9 under high pressure of up to 21.7 GPa using in situ single-crystal synchrotron X-ray diffraction, indicating good phase stability of Al 5 BO 9 .…”