A series of ZnMgNiAl layered double hydroxides (LDHs) containing 20 wt.% Ni and different Zn/Mg molar ratios were prepared by a coprecipitation method, and then were introduced with H2PO4 via a microwave-hydrothermal method. With the resulting mixtures as the precursors, Zn/Mg-modified ZnMgNi–P/Al2O3 catalysts were prepared. The Zn/Mg molar ratio affected the formation of Ni2P and Ni12P5 in nic...

X-ray diffraction was utilized to follow the transformation from β-SiC (3C) to the various α-SiC polytypes in the presence of AlN and Al2O3 additives after hot pressing from 1700 to 2100 ◦C. The 2Hand 6H-polytypes of α-SiC were the predominate polytypes with additions of only AlN or Al2O3, respectively. The amount of 2Hand 6H-polytypes, and subsequently the microstructural morphology of the SiC...

HHigh-k LaAlO3 (LAO) thin films with and without Al2O3 buffer layers were deposited on n-type silicon substrates using a pulsed laser deposition method. The dielectric constant of the LAO thin film increased from 5.2 to 23.1 as its thickness increased from 20 to 500 Å. The effective dielectric constants of the LAO (120 Å)/Si and LAO(105 Å)/Al2O3(15 Å)/Si were 12.5 and 23.2, respectively. The fl...

We report on a GaN metal-oxide-semiconductor field-effect-transistor (MOSFET) using atomic-layer-deposited (ALD) Al2O3 as the gate dielectric. Compared to a GaN metal-semiconductor field-effect-transistor (MESFET) of similar design, the MOSFET exhibits several orders of magnitude lower gate leakage and near three times higher channel current. This implies that the ALD Al2O3/GaN interface is of ...

Nanocrystal HZSM-5 zeolite aggregates with different SiO2/Al2O3 molar ratios were prepared under low temperature and were used to catalyze the conversion of methanol to propylene and butene. The coke location, coke content, and coke species deposited on HZSM-5 aggregates were investigated. The near-graphite carbon on the external surface of HZSM-5 zeolite (SiO2/Al2O3 molar ratio = 400) was dist...

Transformation of Al(NO3)3∙9H2O (upon heating in the range of 20-1200 °C) into blends of amorphous and crystalline boehmite (210-525 °C), amorphous alumina and crystalline γ-Al2O3 (850 °C), and crystalline α-Al2O3 (1100 °C) was analyzed using X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), infrared (IR) spectroscopy, thermogravimetry, and low-temperature nitro...

In this research work, airplane grade aluminum alloy substrate was coated by Al2O3/ TiO2 ceramic coatings in two different compositions as 50:50 and 87:13 using Flame spraying technique. The surface & cross-sectional morphological characterizations of the Al2O3/ TiO2 powders and coatings were performed by scanning electron microscopy (SEM). The microwave absorbing properties of coatings were ex...

Using a reactive force field ~ReaxFF!, we investigated the structural, energetic, and adhesion properties, of both solid and liquid Al/a-Al2O3 interfaces. The ReaxFF was developed solely with ab initio calculations on various phases of Al and Al2O3 and Al-O-H clusters. Our computed lattice constants, elastic constants, surface energies, and calculated work of separation for the solid-solid inte...

The influences of filler size and content on the properties (thermal conductivity, impact strength and tensile strength) of Al2O3/high density polyethylene (HDPE) composites are studied. Thermal conductivity and tensile strength of the composites increase with the decrease of particle size. The dependence of impact strength on the particle size is more complicated. The SEM micrographs of the fr...

We present surface properties of buffer films (AIN and GaN) and Al0.3Gao.zN/Al2O3-High Electron Mobility Transistor (HEMT) structures with/without AIN interlayer grown on High Temperature (HT)-AIN buffer/Al2O3 substrate and Al2O3 substrate. We have found that the GaN surface morphology is step-flow in character and the density of dislocations was about 10(8)-10(9) cm(-2). The AFM measurements a...