Analysis annealing

GIa] Melting in Tamman furnace (graphite cracibles), chemical analysis, annealing followed by water quenching, electrical conductivity and microhardness measurements 950, 700°C, > 4 at% Fe, > 4 at.% P... 

She] Induction melting, chemical analysis, annealing, thermal analysis. X-ray diffraction < 7 mass% C, < 40 mass% W... 

Other methods which are applied to conformational analysis and to generating multiple conformations and which can be regarded as random or stochastic techniques, since they explore the conformational space in a non-deterministic fashion, arc genetic algorithms (GA) [137, 1381 simulation methods, such as molecular dynamics (MD) and Monte Carlo (MC) simulations 1139], as well as simulated annealing [140], All of those approaches and their application to generate ensembles of conformations arc discussed in Chapter II, Section 7.2 in the Handbook. 

Interdiffusion of bilayered thin films also can be measured with XRD. The diffraction pattern initially consists of two peaks from the pure layers and after annealing, the diffracted intensity between these peaks grows because of interdiffusion of the layers. An analysis of this intensity yields the concentration profile, which enables a calculation of diffusion coefficients, and diffusion coefficients cm /s are readily measured. With the use of multilayered specimens, extremely small diffusion coefficients (-10 cm /s) can be measured with XRD. Alternative methods of measuring concentration profiles and diffusion coefficients include depth profiling (which suffers from artifacts), RBS (which can not resolve adjacent elements in the periodic table), and radiotracer methods (which are difficult). For XRD (except for multilayered specimens), there must be a unique relationship between composition and the d-spacings in the initial films and any solid solutions or compounds that form this permits calculation of the compo-... 

This approach is an alternative to quantitative metallography and in the hands of a master gives even more accurate results than the rival method. A more recent development (Chen and Spaepen 1991) is the analysis of the isothermal curve when a material which may be properly amorphous or else nanocrystalline (e.g., a bismuth film vapour-deposited at low temperature) is annealed. The form of the isotherm allows one to distinguish nucleation and growth of a crystalline phase, from the growth of a preexisting nanocrystalline structure. 

Fig. 8. SIMS analysi.s of the ripple experiment. Exces.s deuterium depth profiles for the HDH + DHD bilayer annealed at 118°C (a) The ripple inereasing from 30 to 1080 min. (b) The ripple amplitude deereasing with inereasing time from 1080 to 2880 min [20,57].

Additional isothermal treatments at neighbouring temperatures small step annealing) yield plateau values of resistivity corresponding to equilibrium values at certain temperatures which reflect the order parameter in thermal equilibrium as a function of temperature ( equilibrium curve , curve 4 in Figure 1). This study can be used for an analysis of the kinetics of order-order relaxations (see Figure 3 below). 

For small enough temperature steps (< lOK) during small step annealing the vacancy concentration practically remains constant and corresponds to the instantaneous aimealing temperature. This allows for an easy analysis of SRO-kinetics yielding SRO-relaxation times and SRO-activation enthalpies, which by usual interpretation correspond to H +Hf. 

Improvement of Mm(Ni - Co - A1 - Mn)x type alloys has been achieved in various ways. It was reported that alloys with a nonstoichiometric composition [Mm(Ni - Co - Mn - Al), 4.5 < jc < 4.8] had a larger discharge capacity than those with stoichiometric alloys [26-27J. Using X-ray diffraction analysis, it was found that the larger capacity is dependent on an increase in the unit cell volume of alloys with x=4.5-4.8. It was also reported that annealing treatment improved the durability of this type of alloy. 

Differentiation between the two forms of Ag2C03 is not easy and, from the many methods used, electron spin resonance spectroscopy and thermal analysis have been most successfully applied [757]. The imperfections mentioned above occur in the low temperature decomposition product and are identified as being responsible for enhanced activity in readsorbing C02. Annealing of the residue removes these defects and reduces the reversibility of reaction. 

The phase diagram of the Li-Au system reveals a great deal of complexity, with separate intermetallic phases being formed based on thermal analysis supported by x-ray diffraction at specific compositions. Annealing, sometimes over long time periods, has been undertaken in some cases. 

---