Kinetic Features of Reactive Diffusion in Binary Systems

2006 ◽  
pp. 91-96 ◽  
Author(s):  
M. Kajihara
Keyword(s):  
Binary Systems ◽  
Reactive Diffusion ◽  
Kinetic Features

Kinetic Features of Reactive Diffusion in Binary Systems

2006 ◽  
Vol 249 ◽  
pp. 91-96 ◽  
Author(s):  
M. Kajihara
Keyword(s):  
Temperature Dependence ◽  
Binary Systems ◽  
Reactive Diffusion ◽  
Solubility Range ◽  
Β Phase ◽  
Diffusion Controlled ◽  
Parabolic Relationship ◽  
The Relationship ◽  
Kinetics Of ◽  
Kinetic Features

The temperature dependence of the kinetics of the reactive diffusion was numerically analyzed for a hypothetical binary system composed of one compound phase (β) and two primary solid solution phases (α and γ). The growth rate of the β phase during the reactive diffusion between α and γ phases in a semi-infinite diffusion couple was expressed as a function of the interdiffusion coefficient Dθ and the solubility range of the θ phase ( θ = α, β, γ). For the reactive diffusion controlled by volume diffusion, the thickness l of the β phase is described as a function of the annealing time t by the parabolic relationship l2 = Kt. The equations K = K0 exp(−QK/RT) and Dθ = D0 θexp(−Qθ/RT) were adopted to express K and Dθ as functions of temperature T, respectively. The relationship between the temperature dependence of K and that of Dθ was evaluated according to the following assumptions: the molar volume, the solubility range and the value of D0 θ are constant and equivalent for all the phases. When Qα or Qγ is smaller than Qβ, QK is greater than Qβ. On the other hand, QK is close to Qβ, if both Qα and Qγ are greater than Qβ. In such a case, the temperature dependence of the kinetics represents that of interdiffusion in the growing compound.

Kinetic Features of Solid-State Reactive Diffusion between Au and Sn-Base Solder

2007 ◽  
Vol 539-543 ◽  
pp. 2473-2478 ◽  
Author(s):  
M. Kajihara ◽  
T. Takenaka
Keyword(s):  
Solid State ◽  
Diffusion Couple ◽  
Diffusion Bonding ◽  
Experimental Results ◽  
Reactive Diffusion ◽  
Diffusion Couples ◽  
Kinetics Of ◽  
Bonding Technique ◽  
Kinetic Features

The kinetics of the solid-state reactive diffusion between Au and Sn was experimentally observed using Sn/Au/Sn diffusion couples prepared by a diffusion bonding technique. The diffusion couples were isothermally annealed at a temperature of T = 453 K. Due to annealing, AuSn, AuSn2 and AuSn4 compound layers are formed at the interface in the diffusion couple. The experimental results were used to evaluate quantitatively the effect of Ni on the growth of the Au–Sn compounds. The evaluation indicates that the addition of Ni into Sn between 1 and 5 mass% accelerates the growth of the Au–Sn compounds at T = 433–473 K.

Some Results of the Spectroscopic Study of Four Close Binary Systems of Early Spectral Types

1965 ◽  
Vol 5 ◽  
pp. 120-130
Author(s):  
T. S. Galkina
Keyword(s):  
Spectroscopic Study ◽  
Spectral Type ◽  
Spectroscopic Investigation ◽  
Binary Systems ◽  
Quantitative Information ◽  
Close Binary ◽  
Physical Parameters ◽  
Absorption And Emission ◽  
Close Binary Systems ◽  
Quantitative Estimates

It is necessary to have quantitative estimates of the intensity of lines (both absorption and emission) to obtain the physical parameters of the atmosphere of components.Some years ago at the Crimean observatory we began the spectroscopic investigation of close binary systems of the early spectral type with components WR, Of, O, B to try and obtain more quantitative information from the study of the spectra of the components.

Quasi-Periodic Oscillations in Dwarf Novae

1979 ◽  
Vol 46 ◽  
pp. 77-88
Author(s):  
Edward L. Robinson
Keyword(s):  
Binary Systems ◽  
Outer Edge ◽  
Light Curves ◽  
Close Binary ◽  
Bright Spot ◽  
Dwarf Novae ◽  
Periodic Oscillations ◽  
High Frequencies ◽  
Short Period ◽  
Typical Time

Three distinct kinds of rapid variations have been detected in the light curves of dwarf novae: rapid flickering, short period coherent oscillations, and quasi-periodic oscillations. The rapid flickering is seen in the light curves of most, if not all, dwarf novae, and is especially apparent during minimum light between eruptions. The flickering has a typical time scale of a few minutes or less and a typical amplitude of about .1 mag. The flickering is completely random and unpredictable; the power spectrum of flickering shows only a slow decrease from low to high frequencies. The observations of U Gem by Warner and Nather (1971) showed conclusively that most of the flickering is produced by variations in the luminosity of the bright spot near the outer edge of the accretion disk around the white dwarf in these close binary systems.

Bence-albee after 25 years: A new superior α-factor correction procedure for the quantitative analysis of oxides and silicates

1992 ◽  
Vol 50 (2) ◽  
pp. 1744-1745
Author(s):  
John T. Armstrong
Keyword(s):  
Quantitative Analysis ◽  
Electron Microprobe ◽  
Binary Systems ◽  
Correction Procedure ◽  
Geological Samples ◽  
The Past ◽  
Large Matrix ◽  
Computational Speed ◽  
Microprobe Data ◽  
Geological Sciences

One of the most cited papers in the geological sciences has been that of Albee and Bence on the use of empirical " α -factors" to correct quantitative electron microprobe data. During the past 25 years this method has remained the most commonly used correction for geological samples, despite the facts that few investigators have actually determined empirical α-factors, but instead employ tables of calculated α-factors using one of the conventional "ZAF" correction programs; a number of investigators have shown that the assumption that an α-factor is constant in binary systems where there are large matrix corrections is incorrect (e.g, 2-3); and the procedure’s desirability in terms of program size and computational speed is much less important today because of developments in computing capabilities. The question thus exists whether it is time to honorably retire the Bence-Albee procedure and turn to more modern, robust correction methods. This paper proposes that, although it is perhaps time to retire the original Bence-Albee procedure, it should be replaced by a similar method based on compositiondependent polynomial α-factor expressions.

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