Diffusion of Nb in Nb-H Alloys

2005 ◽  
Vol 237-240 ◽  
pp. 346-351
Author(s):  
Yoshihiro Yamazaki ◽  
Takahiro Iida ◽  
Yoshiaki Iijima ◽  
Yuh Fukai
Keyword(s):  
Diffusion Coefficient ◽  
Activation Energies ◽  
The Self ◽  
Exponential Factor ◽  
Temperature Range ◽  
Self Diffusion ◽  
Diffusion Enhancement ◽  
The Difference ◽  
Self Diffusion Coefficient ◽  
Hydrogen Dissolution

Self-diffusion coefficient of 95Nb in NbHx alloys (x=0.05,0.25 and 0.3) has been determined in the temperature range from 823 to 1323 K by using a serial sputter-microsectioning technique. The self-diffusion coefficient of Nb in the NbHx alloys are larger than that in Nb, suggesting that vacancies are formed by hydrogen dissolution, that is, the formation of hydrogen-induced vacancies. The value of the pre-exponential factor for the Nb diffusion in the NbH0.05 alloy is five times larger than that in Nb, while the difference in the activation energies between the NbH0.05 alloy and pure Nb is small. The self-diffusion enhancement in the NbH0.05 alloy is mainly caused by lowering in vibrational frequencies of atoms in the immediate neighborhood of hydrogen-induced vacancies.

Self-Diffusion of Tl+ in Molten Thalium Nitrate

1977 ◽  
Vol 32 (12) ◽  
pp. 1433-1434
Author(s):  
S. Zuca ◽  
M. Constantinescu
Keyword(s):  
Diffusion Coefficient ◽  
Melting Point ◽  
The Self ◽  
Ionic Interactions ◽  
Temperature Range ◽  
Self Diffusion ◽  
Capillary Method ◽  
Self Diffusion Coefficient

Abstract The self-diffusion coefficient of Tl+ in molten TlNO3 in a temperature range of about 100° above the melting point was measured by the "diffusion-into-the capillary" method. The obtained results are discussed in terms of ionic interactions occuring in TlNO3 melt.

Grain boundary self-diffusion in Ni: Effect of boundary inclination

2005 ◽  
Vol 20 (5) ◽  
pp. 1146-1153 ◽  
Author(s):  
Mikhail I. Mendelev ◽  
Hao Zhang ◽  
David J. Srolovitz
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Boundary Plane ◽  
The Self ◽  
High Symmetry ◽  
Exponential Factor ◽  
Self Diffusion ◽  
Arrhenius Function ◽  
Self Diffusion Coefficient

We examined the influence of the boundary plane on grain-boundary diffusion in Ni through a series of molecular dynamics simulations. A series of 〈010〉 ∑5 tilt boundaries, including several high symmetry and low symmetry boundary planes, were considered. The self-diffusion coefficient is a strong function of boundary inclination at low temperature but is almost independent of inclination at high temperature. At all temperatures, the self-diffusion coefficients are low when at least one of the two grains has a normal with low Miller indices. The grain boundary self-diffusion coefficient is an Arrhenius function of temperature. The logarithm of the pre-exponential factor in the Arrhenius expression was shown to be nearly proportional to the activation energy for diffusion. The activation energy for self-diffusion in a (103) symmetric tilt boundary is much higher than in boundaries with other inclinations. We discuss the origin of the boundary plane density–diffusion coefficient correlation.

Self-Diffusion in Liquid Antimony

1977 ◽  
Vol 32 (9) ◽  
pp. 1021-1024 ◽  
Author(s):  
Peter Lamparter ◽  
Siegfried Steeb
Keyword(s):  
Diffusion Coefficient ◽  
Measuring Method ◽  
The Self ◽  
Temperature Range ◽  
Self Diffusion ◽  
Capillary Method ◽  
Self Diffusion Coefficient

AbstractThe diffusion of radioactive Sb in liquid Sb has been measured in the temperature range from 672 °C to 1029 °C by use of the long-capillary method. A measuring method is described by which the sectioning of the specimens can be avoided. The self-diffusion coefficient is represented by the equationD= (5.46 + 0.78) · 10-4 ·exp[- (4230±310)/R T]cm2 sec-1. It is concluded that liquid Sb shows semi-metallic behaviour.

Self-diffusion of Tin in a liquid Tin-Lead alloy at the Eutectic Composition

1976 ◽  
Vol 31 (8) ◽  
pp. 1024 ◽  
Author(s):  
D. H. Kurlat ◽  
M. Rosen ◽  
G. Quintana
Keyword(s):  
Diffusion Coefficient ◽  
Eutectic Composition ◽  
The Self ◽  
Lead Alloy ◽  
Shear Cell ◽  
Temperature Range ◽  
Self Diffusion ◽  
Cluster Hypothesis ◽  
Liquid Tin ◽  
Self Diffusion Coefficient

Abstract By the shear cell technique, the self-diffusion coefficient (DSn) of tin in a liquid Sn - 38.1 wt% Pb alloy has been measured in the temperature range 466 to 786 K. The slope of the DSn vs. T curve decreases up to about 573 K, where it gets constant. This behaviour may be explained by the cluster hypothesis.

Investigation on the Diffusion Behavior of Mo-Ni Interface

2010 ◽  
Vol 152-153 ◽  
pp. 1607-1610 ◽  
Author(s):  
Wei Chan Cao ◽  
Shu Hua Liang ◽  
Yue Xin Xue ◽  
Xian Hui Wang
Keyword(s):  
Solid Solution ◽  
Diffusion Coefficient ◽  
Electron Microscope ◽  
Intermetallic Compound ◽  
Diffusion Layer ◽  
Interdiffusion Coefficient ◽  
The Self ◽  
Diffusion Behavior ◽  
Self Diffusion ◽  
Self Diffusion Coefficient

In order to gain a deep insight into the mechanism of Ni-doped Mo activated sintering process, the diffusion behavior of Mo-Ni interface was studied utilizing a Mo-Ni diffusion couple. The phase structure and composition on the diffusion layer were characterized and analyzed by means of scanning electron microscope and transmission electron microscope, the self diffusion coefficient and interdiffusion coefficient were calculated. The results show that a diffusion layer is formed between Mo and Ni after sintering at 1223k for 1h, which is comprised of a δ-NiMo intermetallic compound and a limit solid solution containing small amounts of nickel. The self diffusion coefficient and interdiffusion coefficient are 2.068×10-18cm2/s and 4.5×10-12cm2/s, respectively. It is suggested that the diffusion rate of Mo in δ-NiMo intermetallic compound and a limit solid solution containing small amounts of nickel is 106 times bigger than that of self diffusion, and the intermetallic compound layer provides a short diffusion path for Mo activated sintering.

Sign in / Sign up

Export Citation Format

Share Document