Влияние химических и фазовых превращений в оксидно-гидроксидной оболочке частиц алюминия различных размеров на закономерности их окисления при нагревании в воздухе

Al, независимом формировании и росте зародышей фазы оксида алюминия. Установлено нивелирование влияния размеров частиц Al на кинетику их окисления при переходе от микронного к субмикронному размерному диапазону.Relevance of researching the rules of Al submicron and nanopowders oxidation is determined by the prospects of the powders use as additives in solid fuels and in pyrotechnic compositions, as reagents in preparation of intermetallic compounds and composites. The aim of the research is to determine the influence of physicochemical processes in oxide-hydroxide shell of Al particles on mechanism of oxidation of Al micron, submicron and nanopowders when heated in air. The methods used in the research: differential thermal analysis (SDT Q 600), dynamic light scattering (Microsizer-201, Nanosizer ZS), scanning (Quanta 200 3D) and transmission electron microscopy (JEOL JEM-3010), atomic-emission spectroscopy (iCAP 6300 Duo), X-ray fluorescence analysis (Quant’X), X-ray diffraction (Shimadzu XRD 6000), infrared spectroscopy (FTIR Nicolet 5700), X-ray photoelectron spectroscopy (ESCA 310). The results: The paper demonstrates the determining influence of phase and chemical transformations in superficial oxide shells of Al particles of micron and submicron sizes (decomposition of Al hydroxides, crystallization of amorphous oxide, phase transformations) on temperature intervals and rate of Al powders oxidation. The influence of phase transformations of Al oxide on low and high temperature oxidation when linearly heated in air is studied. The author has determined the details of reaction surface development and oxide nuclei formation and growth during Al oxidation which consist in strong oxidation localization on the surface of Al submicron or nanoparticles and by independent formation and growth of the oxide nuclei. The leveling of the size effect on Al particles oxidation kinetics was proved when Al particle size decreased from micron to submicron range.