Control on nanostructured quaternary Ti–Al–O–B composite synthesized via electrospinning method, from nanoparticles to nanowhiskers

Abstract

The nanostructured powder of multicomponent oxides, borides, and borates is widely used due to its high hardness, corrosion resistance, high melting point, insulating, and abrasive. In the present work, the effect of boron content on the morphology of electrospun multicomponent oxide, boride, and borate nanostructures in a quaternary Ti–Al–O–B system was investigated. Different molar ratios of B/(Ti + Al) (0.8, 1.6, and 2.4) were employed and evaluated. Imaging with the field emission scanning electron microscope (FESEM) and the transmission electron microscope (TEM) revealed that after one hour of thermal treatment at 1100 °C, the hybrid electrospun nanofibers (NFs) in the fibrous platform transformed into nanoparticles (NPs), nano-needles, and nano-whiskers at B/(Ti + Al) molar ratios of 0.8, 1.6, and 2.4, respectively. The binding energies were investigated by X-ray photoelectron spectroscopy (XPS), whereas the phase study was conducted via the X-ray diffraction (XRD) technique. The results confirmed the formation of nanostructured ceramic powder platforms composed of multiple components, namely oxides (e.g., B-doped TiO2; Al2O3), borides (TiB, TiB2, Ti2B5, TiB12, and AlB2), and borates (TiBO3; Al18B4O33). Simultaneous thermal analysis (STA) of the Ti–Al–O–B mats indicated that the borides and borates formed consecutively at temperatures above 800 °C through reactions involving molten B2O3. We found that the obtained NPs were well arranged and sintered together throughout the fibers.