The synthesis of solid solutions in the HfB2-ZrB2 system was conducted by mechanically induced self-sustaining reaction (MSR) processes under an inert atmosphere from elemental mixtures of Hf, Zr, and B. The stoichiometry of the Hf1-xZrxB2 solid solution phase was controlled by adjusting the Hf/Zr/B atomic ratio in the starting mixture. Composite materials with SiC were…
Combined kinetic analysis has been applied for the first time to the thermal degradation of polymeric materials. The combined kinetic analysis allows the determination of the kinetic parameters from the simultaneous analysis of a set of experimental curves recorded under any thermal schedule. The method does not make any assumptions about the kinetic model or…
A new method for preparing high surface area α-alumina from urban waste is proposed. The method consists of the precipitation of a precursor that contains bohemite mixed with a linear polymer and subsequently the thermal decomposition of the precursor by heating in nitrogen and air to 1200 °C. The resulting α-alumina consists of nanocrystals of…
The machinability of materials is a dynamic field with enormous implications in different industrial sectors because manufacturers are constantly looking for improvements that can increase the overall productivity. Manufacturers of cutting tool inserts need to develop products that can perform at higher speeds and last longer under increasingly rigorous operating conditions. It has been revealed…
The recent paper by Jankovic et al. [B. Janković, B. Adnađevic, J. Jovanović; Thermochimica Acta 452 (2007) 106] and other similar papers have raised a problem which needs to be resolved. These authors use the method of Kennedy and Clark [J.A. Kennedy, S.M. Clark, Thermochimica Acta 307 (1997) 27] which is conceptually erroneous; this is…
Los materiales multiferroicos, aquellos que presentan simultaneamente dos o mas propiedades ferroicas, tienen un gran interés en la actualidad debido al gran número de apli-caciones que pueden derivarse de sus propiedades. A pesar del interés suscitado por estos materiales, Su dificultad de preparación por métodos convencionales como fases puras de estequiometria controlada y pureza adecuada…
The dynamic heating rate method developed by TA Instruments (Hi-ResTM) is a kind of sample controlled thermal analysis in which a linear relationship between the logarithm of the heating rate and the rate of mass change is imposed. It is shown in this paper that the reacted fraction at the maximum reaction rate strongly depends…
TiCxN1-x-based powdered cermets were synthesized by a one step mechanically induced self-sustaining reaction (MSR) process from mixtures of elemental powders, and subsequently sintered by a pressureless method. The composition and microstructure of the ceramic and binder phases before and after the sintering process were studied by X-ray diffraction, scanning and transmission electron microscopy, and electron…
Emanation thermal analysis (ETA), thermogravimetry and high temperature XRD were used to characterize the thermal behavior during dehydration of natural Na montmorillonite (Upton Wyoming, USA) and homoionic montmorillonite (MMT) samples saturated with different cations, i.e. Li+, Cs+, NH4+, Mg2+ and Al3+. ETA results characterized radon mobility and microstructure changes that accompanied the mass loss of…
