Rheological behavior of aqueous suspensions containing nanometer-sized powders is of relevance to many branches of industry. Unusually high viscosities observed for suspensions of nanoparticles compared to those of micron size powders cannot be explained by current viscosity models. Formation of so-called hydration layer on alumina nanoparticles in water was hypothesized, but never observed exp...

The aluminum bronze matrix alumina composites using hot press and resin infiltration were investigated to study their porosities, hardness, bending strengths, and microstructures. The experiment results show that the hardness of the sintered composites with the decrease of porosity increases. The composites without and with resin infiltration have about HRF 42-61 of about 34-40% of porosity and...

Wear of the surface is the major problem of all materials. This wear can be of many types and there can be several methods of reducing wear. Coating on the surface of material is one of them. On M.S substrate, thermal spray coating is done using Detonation spray gun and coating powders used is a mixture of oxides (Al2O3-13TiO2). The thermal-sprayed coatings are characterized by SEM, EDS analyse...

Sintering behavior with and without external stress was investigated using undoped and doped (1500 ppm yttria) sub-micron a-alumina powders. The yttria doped alumina showed anomalous behavior with grain size around 0.9 pm, a second peak in densification rate during free sintering and a stagnation followed by a steep increase in flow stress during sinter forging. These were thought to correspond...

The sintering behaviour of several green compacts made with olivine or olivine/alumina powder blends has been examined. To this goal, powders were attrition milled, uniaxially pressed into specimens and air sintered at temperatures ranging from 1100 to 1300 °C. The resulting samples were characterized by water absorption, shrinkage, phase composition and density. Compositions containing 5%, 10%...

Water-vapor adsorption on poorly crystalline boehmite (PCB) was studied using a gravimetric FTIR apparatus that measured FTIR spectra and water adsorption isotherms simultaneously. The intensity of the delta(HOH) band of adsorbed water changed linearly with water content and this linear relationship was used to determine the dry mass of the sample. Adsorption and desorption isotherms of PCB sho...

Introduction: Acrylic resins have been used successfully as denture bases. However, acrylic resin denture base materials are brittle and have poor strength and thermal conductivity. Therefore, it is essential to improve the flexural strength of heat polymerized acrylic resin. The present study aimed to evaluate and compare the flexural strength of heated polymerized acrylic res...

The tunneling magnetoresistance sTMRd of thin dielectric tunnel barriers that are sandwiched between pairs of ferromagnetic metal thin films is highly sensitive to the barrier layer atomic scale thickness, the uniformity in thickness, and the composition. Widely used AlOx barriers are formed by the oxidation of 1–2 nm thick aluminum layers vapor deposited onto one of the ferromagnetic metal ele...

The thermoluminescence (TL) after excitation by UV or X-rays radiation of doped α-alumina powders is investigated. In the case of zirconia, the alumina-zirconia composites present five of the characteristic peaks of zirconia at –170, –145, –90, 0 and 95°C. After a thermal treatment of mixed oxides, a new peak is observed at –35°C in TL. This peak reveals the presence of stabilized tetragonal zi...