Elastic and plastic properties of metals and Young's modulus of ceramics are determined in the microindentation regime by continuous measurements of load versus depth of penetration with spherical indenters. Calibration procedures, usually applied in nanoindentation experiments, are not needed in the microregime where spherical indenters (rather than sharp indenters with microscopical spherical tips) can be manufactured. As indenters of larger diameters are used, the elastic response of the specimen can be probed during the loading stage of the indentation tests (and not only during unloading, as is the case with nanoindenters). Hence, an accurate determination of Young's modulus can be achieved without a prior knowledge of possible “piling up” or “sinking in” which may occur at the perimeter of the contact area. The contact response of materials is shown to undergo four distinct regions: (i) pre-Hertzian regime, (ii) Hertzian regime, (iii) small-scale plasticity, and (iv) large-scale plasticity. A general methodology for estimation of yield strength and hardening exponent of metals is proposed in the last regime.

The changes in the valence electron states of CaSi2 during the chemical reaction with H2O have been investigated by Auger Valence Electron Spectroscopy (AVES). In order to study the reaction process, the reaction was precisely controlled by applying dc voltage between Pt electrode and CaSi2 specimen. The Si[2s, 2p,V] Auger spectra of CaSi2 specimen remain unchanged under the applied voltage lower than −15 V relative to the Pt electrode in H2O. At higher applied voltage, 3p components of Si[2s, 2p, V] (V = 3s, 3p) Auger spectra get weak while the 3s components increase drastically. The peak position due to Ca[2p, 3p, 3p] transitions gradually shifted toward the lower energy side by raising the applied voltage. The peak shift is due to the formation of Ca–O bonds in CaSi2. A new peak, which arises from the split of the valence electron states in Ca atoms due to the Ca–O bonds, appeared in Ca[2p, 3p,V] Auger spectra for CaSi2 after the reaction with H2O.

A commercial piezoelectric acoustic emission transducer has been used in conjunction with nanoindentation techniques to study the relationship between acoustic emission signals and discrete physical events to identify the type and strength of an event. Indentations into tungsten and iron single crystals have been used to study dislocation generation and passive film failure. In addition, indentations made into a thin nitride film on sapphire have been used to cause film delaminations. Parameters such as signal rise time and frequency for a piezoelectric sensor are related to sample geometry, and not to the type of event which caused the acoustic emission signal. As a possible calibration for acoustic emission sensors, the most meaningful parameter is the acoustic emission energy, which has been shown to scale with the elastic energy released during the event. The measured values of elastic energy released correspond very closely to those calculated using Hertzian contact mechanics.

Aluminum dross tailings, an industrial waste from the Egyptian Aluminium Company (Egyptalum), were used to produce two types of alums, namely, aluminum sulfate alum and ammonium aluminum alum via two separate processes. The first process involved leaching the impurities using dilute H2SO4 at different solid/liquid ratios and temperatures in the form of soluble sulfates. Some dissolved aluminum was recovered as ammonium aluminum sulfate. The second process involved extraction of aluminum sulfate from the purified dross produced after leaching. This was carried out under atmospheric pressure using different concentrations of H2SO4. Influence of temperature, time of reaction, and acid concentration on leaching and extraction processes were studied. X-ray diffraction, atomic absorption spectrometry, and thermal analysis techniques were used.