Inhibition of Oxide Formation on Aluminum Nanoparticles by Transition Metal Coating

Abstract

Nanometer-sized aluminum powder was synthesized by thermal decomposition of an alane solution in the presence of a titanium catalyst under an inert atmosphere. The resulting material, formally devoid of an oxide layer, was used to reduce complexes of gold, nickel, palladium, and silver. The reduction process yielded materials that contained the transition metal at a level between 1 and 3 atom % on a metals basis, as determined by inductively coupled plasma atomic emission spectroscopy and energy dispersive spectroscopy. After exposure to air at ambient conditions, the transition metal treated aluminum materials were found to contain less aluminum oxide than an aluminum sample that was not treated with a transition metal. The nickel treated sample contained as much or more metallic aluminum as the untreated aluminum sample, indicating that the passivating layer in the nickel treated aluminum was highly efficient at protecting the underlying aluminum.

Metal-based Inkjet Inks for Printed Electronics

“…The main challenge in replacing Ag by the much cheaper metals, Cu and Al, is in avoiding their oxidation at ambient conditions, which usually requires rather sophisticated reaction conditions -the use of hydrocarbon solvents, low precursor concentration and inert atmosphere [19,[21][22][23][24][25][26][27]. For example, Al undergoes rapid oxidation in air (~100 picoseconds) with formation of a dense thin amorphous Al 2 O 3 layer (2-6 nm) [28,29] that results in loss of electrical conductivity and makes aluminum inapplicable for conductive ink formulations. Oxidation of Cu NPs is less rapid compared to Al NPs, especially in the presence of an excess of reducing agent, as we reported recently [19,24].…”

Nano Engineered Energetic Materials (NEEM)

“…In 2005, Higa and co-workers reported the use of transition metals to inhibit the formation of an oxide layer over the surface of aluminum nanoparticles [50]. They claimed that treatment of aluminum particles with solutions of certain transition metal complexes resulted in the deposition of a uniform coat of the zerovalent transition metal [50].…”

“…They claimed that treatment of aluminum particles with solutions of certain transition metal complexes resulted in the deposition of a uniform coat of the zerovalent transition metal [50]. These reactions, which take advantage of the strongly reducing nature of metallic aluminum, may be termed redox transmetalation reactions [51][52][53][54][55].…”

Chemical and Morphological Inhomogeneity of Aluminum Metal and Oxides from Soft X-ray Spectromicroscopy

“…42,43 These analytes were specifically chosen because they provided a range of particle sizes, compositions, surface chemistries, and reactivities. [44][45][46][47] For example, previous studies have shown that protecting agents including organic ligands 40,[48][49][50][51][52][53][54] and polymer [55][56][57] or metal coatings 44,58,59 enhanced reactivity properties and provided chemical control over structural attributes like particle size and monodispersity. The STXM-XAS results were consistent with earlier spectromicroscopy studies, 26,55,60 and also revealed new differences in the surface and micron-scale speciation of Al nanoparticles.…”