Annealing kinetic parameters

Previous works [98] have also revealed that (i) the nature of the precursors or (ii) the annealing kinetic parameters play a significant role for the stabilization of the metastable phase. Indeed, for chloride-based precursors, the pyrochlore structure is directly obtained. This is explained by the high affinity of Q anions relative to Ln ", which prevents the formation of the complex with 2,4-pentane-dione and thus the formation of a homogeneous gel. In addition, for the kinetic aspect, the layered perovskite phase is favored for rapid annealing or quenching directly at 950 °C. 

For example the behavior of magnesia, alumina, and thoria powders were characterized by this method. The DSA results of thoria powder are demonstrated in Fig. 5, indicating the kinetics of the annealing of surface roughness. The kinetic parameters of this process taking place in the temperature interval 705-825° C were determined [26]. 

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). 

It is important to note that Eqs. 5, 8, and 9 were derived entirely from a silicon material balance and the assumption that physical sputtering is the only silicon loss mechanism thus these equations are independent of the kinetic assumptions incorporated into Eqs. 1, 2, and 7. This is an important point because several of these kinetic assumptions are questionable for example, Eq. 2 assumes a radical dominated mechanism for X= 0, but bombardment-induced processes may dominate for small oxide thickness. Moreover, ballistic transport is not included in Eq. 1, but this may be the dominant transport mechanism through the first 40 A of oxide. Finally, the first 40 A of oxide may be annealed by the bombarding ions, so the diffusion coefficient may not be a constant throughout the oxide layer. In spite of these objections, Eq. 2 is a three parameter kinetic model (k, Cs, and D), and it should not be rejected until clear experimental evidence shows that a more complex kinetic scheme is required. 

Abstract. One more method of study of the short-range order kinetics of H-atoms over tetrahedral interstices in lutetium (Lu) is proposed. It can be realized by the using of available data of measurements of heat capacity for h.c.p.-Lu-H interstitial solid solutions during the isothermal annealing. Comparison of estimated-parameters data from heat capacity and residual electrical-resistivity measurements is performed. It is shown that kinetics of heat capacity and residual resistivity at low temperatures is caused by the unique nature (short-range order relaxation) and can be described by two relaxation times at least. 

The aimealing kinetics of the light-induced defects are shown in Fig. 6.29. Several hours at 130 °C are needed to anneal the defects completely, but only a few minutes at 200 C. The relaxation is nonexponential, and in the initial measurements of the decay the results were analyzed in terms of a distribution of time constants, Eq. (6.78) (Stutzmann, Jackson and Tsai 1986). The distribution is centered close to 1 eV with a width of about 0.2 eV. Subsequently it was found that the decay fits a stretched exponential, as is shown in Fig. 6.29. The parameters of the decay-the dispersion, p, and the temperature dependence of the decay time, t - are similar to those found for the thermal relaxation data and so are consistent with the same mechanism of hydrogen diffusion. The data are included in Fig. 6.23 which describes the general relation between x and D,. The annealing is therefore the process of relaxation to the equilibrium state with a low defect density. 

The nature and strength of vacancy-vacancy interactions have scarcely been investigated, although they drive the thermodynamics of vacancy ordering on defective surfaces, and are thus key quantities to understand the numerous reconstructions observed on surfaces annealed in vacuum [1,2]. However, the ordering process may be inhibited by kinetic effects, relying on parameters, such as the activation energy for vacancy diffusion and the temperature. On MgO(lOO), vacancies have been found to weakly repell... 

The kinetics of the oxygen-induced restructuring process as well as the resulting surface phases depend on sample temperature, annealing time, gas pressure, and reduction state (i.e., age or color) of the crystal. These parameters have been investigated in detail by Li et al. [9,98,100-102]. For example. Fig. 12 shows the effect of annealing in 1x10- mbar O2 at various... 

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