Diffusion Parameters Determination by a Non-Destructive Technique with an Assumption of Mass Exchange on the Surface

2006 ◽  
Vol 249 ◽  
pp. 189-192
Author(s):  
O.B. Bodnar ◽  
I.M. Aristova ◽  
A.A. Mazilkin ◽  
A.N. Chaika ◽  
P.Yu Popov
Keyword(s):  
Diffusion Mechanism ◽  
Bulk Diffusion ◽  
Surface Concentration ◽  
Sample Surface ◽  
Initial Distribution ◽  
Dopant Atom ◽  
Subsurface Region ◽  
Diffusion Parameters ◽  
Radiation Damages ◽  
Non Destructive

Theoretical base for non-destructive diffusion parameters determination technique in solids taking into account the dopant flux from the sample surface is presented. Diffusion of the nitrogen implanted in the tungsten single crystals was determined in temperature range 700–820°C. Surface concentration of nitrogen was obtained by Auger electron spectroscopy. Initial distribution of the nitrogen in subsurface region was measured by secondary-ion mass-spectroscopy. Two dopant atom fluxes found in subsurface region of the ion-implanted material are supposed to connect with the radiation damages and with the bulk diffusion mechanism.

Non-Destructive Method of Diffusion Parameters Determination in Solids

2005 ◽  
Vol 237-240 ◽  
pp. 438-443 ◽  
Author(s):  
O.B. Bodnar ◽  
I.M. Aristova ◽  
A.A. Mazilkin ◽  
A.N. Chaika ◽  
L.N. Pronina
Keyword(s):  
Diffusion Mechanism ◽  
Bulk Diffusion ◽  
Surface Concentration ◽  
Initial Distribution ◽  
Dopant Atom ◽  
X Ray Diffraction ◽  
Diffusion Parameters ◽  
Transmission Electron ◽  
Radiation Damages ◽  
Non Destructive

Diffusion of nitrogen implanted in tungsten and molybdenum single crystals has been investigated at temperature about 0.3 Tm (Tm is the melting point). Existence of several dopant atom fluxes is found in subsurface region of the ion implanted material. The diffusion coefficients of the nitrogen connected with the radiation damages and that with the bulk diffusion mechanism are determined. Change of the nitrogen surface concentration has been measured by Auger electron spectroscopy. Initial distribution of the nitrogen and diffusion profiles for various annealing time have been determined by secondary-ion mass-spectroscopy technique. Transmission electron microscopy and X-ray diffraction investigations were used to study the microstructure and phase state of the implanted samples.

Spatial Evaluation of Pore Pressure Variations Related to Rainfall from Seismic Velocity Changes

2021 ◽  
Author(s):  
Rezkia Dewi Andajani ◽  
Takeshi Tsuji ◽  
Roel Snieder ◽  
Tatsunori Ikeda
Keyword(s):  
Pore Pressure ◽  
Negative Correlation ◽  
Ambient Noise ◽  
Seismic Velocity ◽  
Diffusion Mechanism ◽  
Velocity Change ◽  
Diffusion Parameters ◽  
The Status ◽  
Seismic Velocity Changes ◽  
Velocity Changes

<p>Crustal pore pressure, which could trigger seismicity and volcanic activity, varies with fluid invasion. Various studies have discussed the potential of using seismic velocity changes from ambient noise to evaluate pore pressure conditions, especially due to rainfall perturbations. Although the influence of rainfall on seismic velocity changes has been reported, consideration of the spatial influence on rainfall towards seismic velocity and its mechanism have not been well understood. We investigated the mechanism of rainfall-induced pore pressure diffusion in southwestern Japan, using seismic velocity change (Vs) inferred from ambient noise. We modeled pore pressure changes from rainfall data based on a diffusion mechanism at the locations where infiltration is indicated. By calculating the correlation between Vs changes and the modeled pore pressure with various hydraulic diffusion parameters, the optimum hydraulic diffusion parameter was obtained. We estimated the diffusion parameters with the highest negative correlation between pore pressure and Vs change because a negative correlation indicates pore pressure increase due to diffusion induced by groundwater load. Furthermore, the spatial variation of the hydraulic diffusivity infers the heterogeneity of the rocks in different locations. This finding suggests that the response of pore pressure induced by rainfall percolation depends on location.  We show that seismic velocity monitoring can be used to evaluate the status of pore pressure at different locations, which is useful for fluid injection, CO<sub>2</sub> wellbore storage, and geothermal development.</p>

scholarly journals Dynamic Observation of Interfacial IMC Evolution and Fracture Mechanism of Sn2.5Ag0.7Cu0.1RE/Cu Lead-Free Solder Joints during Isothermal Aging

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 831 ◽  
Author(s):  
Di Zhao ◽  
Keke Zhang ◽  
Ning Ma ◽  
Shijie Li ◽  
Chenxiang Yin ◽  
...  
Keyword(s):  
Growth Rate ◽  
Fracture Mechanism ◽  
Isothermal Aging ◽  
Solder Joints ◽  
Diffusion Mechanism ◽  
Bulk Diffusion ◽  
Cu Substrate ◽  
Dynamic Observation ◽  
Free Solder ◽  
The Relationship

Dynamic observation of the microstructure evolution of Sn2.5Ag0.7Cu0.1RE/Cu solder joints and the relationship between the interfacial intermetallic compound (IMC) and the mechanical properties of the solder joints were investigated during isothermal aging. The results showed that the original single scallop-type Cu6Sn5 IMC gradually evolved into a planar double-layer IMC consisting of Cu6Sn5 and Cu3Sn IMCs with isothermal aging. In particular, the Cu3Sn IMC grew towards the Cu substrate and the solder seam sides; growth toward the Cu substrate side was dominant during the isothermal aging process. The growth of Cu3Sn IMC depended on the accumulated time at a certain temperature, where the growth rate of Cu3Sn was higher than that of Cu6Sn5. Additionally, the growth of the interfacial IMC was mainly controlled by bulk diffusion mechanism, where the activation energies of Cu6Sn5 and Cu3Sn were 74.7 and 86.6 kJ/mol, respectively. The growth rate of Cu3Sn was slightly faster than that of Cu6Sn5 during isothermal aging. With increasing isothermal aging time, the shear strength of the solder joints decreased and showed a linear relationship with the thickness of Cu3Sn. The fracture mechanism of the solder joints changed from ductile fracture to brittle fracture, and the fracture pathway transferred from the solder seam to the interfacial IMC layer.

Laser cleaning of the contaminations on the surface of tire mould

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744100 ◽  
Author(s):  
Yayun Ye ◽  
Baoshen Jia ◽  
Jing Chen ◽  
Yilan Jiang ◽  
Hongping Tang ◽  
...  
Keyword(s):  
Energy Range ◽  
Laser Irradiation ◽  
Cast Steel ◽  
Sample Surface ◽  
Steel Sample ◽  
Laser Cleaning ◽  
Environmental Friendly ◽  
Mould Surface ◽  
Laser Induced Damage ◽  
Non Destructive

During the manufacturing of tires, surface pollutants on tire mould will lead to the production of unqualified tires. Tire moulds need to be regularly cleaned. Laser cleaning is recognized as a non-destructive, effective, precise and environmental friendly method. In this paper, laser cleaning was used to remove contaminants on tire mould surface. First, laser induced damage experiments were performed. The results showed that the roughness and hardness of the cast steel sample surface seldom changed under the energy range of 140.1–580.2 mJ laser irradiation 1 pulse and the energy range of 44.7–168.9 mJ laser irradiation 100 pulses. In the laser cleaning experiments, the cleaning thresholds and the optimal cleaning parameters were obtained. Results indicated that laser cleaning was safe and effective for tire mould contamination removal.

Catalysis with Inorganic Membranes

MRS Bulletin ◽  
1994 ◽  
Vol 19 (4) ◽  
pp. 34-39 ◽  
Author(s):  
M.P. Harold ◽  
C. Lee ◽  
A.J. Burggraaf ◽  
K. Keizer ◽  
V.T. Zaspalis ◽  
...  
Keyword(s):  
Thin Film ◽  
Pore Size ◽  
Diffusion Mechanism ◽  
Knudsen Diffusion ◽  
Bulk Diffusion ◽  
Molecular Transport ◽  
Mean Free Path ◽  
Specific Interactions ◽  
Inorganic Membranes ◽  
Introductory Article

Catalytic inorganic membranes are among the most challenging and intriguing porous materials. Consisting of a thin film of mesoporous or microporous inorganic material deposited on a macroporous material, catalytic membranes are multifunctional materials that must be engineered for both chemical and physical properties. New approaches to carrying out chemical reactions are possible by tailoring the membrane catalytic activity and selectivity, permselectivity, and other thin film properties. Readers are referred to several recent reviews of inorganic membranes, in particular, Zaspalis and Burggraaf, Armor, Gellings and Bouwmeister, Hsieh, Stoukides, and Tsotsis et al.Inorganic membranes are most conveniently classified according to pore size (see introductory article). Of particular importance is the ratio of the pore size to the molecular mean free path (MFP). Decreasing pore dimensions lead to increased selectivity with corresponding loss of permeability. Macroporous membranes have a pore size much larger than the MFP, leading to molecular (bulk) diffusion or viscous flow. Knudsen diffusion dominates in the mesoporous regime, where the pore size is comparable to the MFP. In addition, surface diffusion of the molecules along the pore walls may contribute, leading to an enhanced flux of the adsorbed species along the walls. The microporous regime is encountered when the pore size is comparable to the molecules. This regime makes possible much higher permselectivities, which depend on both molecular size and specific interactions with the solid. Finally, in dense membranes, molecular transport occurs through a solution-diffusion mechanism, which also involves specific interactions between the solute and membrane.

Electromigration Lifetimes of Single Crystal Aluminum Lines with Different Crystallographic Orientations

1994 ◽  
Vol 338 ◽  
Author(s):  
Y.-C. Joo ◽  
C.V. Thompson
Keyword(s):  
Activation Energy ◽  
Single Crystal ◽  
Diffusion Mechanism ◽  
Failure Mechanisms ◽  
Bulk Diffusion ◽  
Time To Failure ◽  
Interface Diffusion ◽  
Test Conditions ◽  
Service Conditions ◽  
Crystallographic Orientations

ABSTRACTNear-bamboo interconnects are susceptible to failure either at polygranular clusters or within bamboo grains (transgranular failure). Polygranular failure mechanisms are often dominant in lines with near-bamboo structures at test conditions, but at service conditions, transgranular failure mechanisms are expected to dominate. In order to study the temperature and current density dependence as well as the crystallographic dependence of these transgranular failure mechanisms, it is necessary to isolate them from other mechanisms. To do this, we have studied single crystal Al lines on oxidized silicon.We have tested lifetimes of passivated and unpassivated Al single crystal lines with various textures. In both passivated and unpassivated lines, the median time to failure, t50, was found to be texture-dependent, with t50(l11) > t50(133) > t50(110), and with t50(111) ∼ 10×t50(110). The activation energy for failure for both passivated and unpassivated (110) single crystal lines was about 1 eV. This value differs from that of aluminum bulk diffusion (1.4 eV), suggesting that interface diffusion is the dominant diffusion mechanism in these lines, and perhaps in bamboo regions of near-bamboo lines as well.

Effect of Microalloying with Ti or Cr on the Corrosion Behavior of Al-Ni-Y Amorphous Alloys

CORROSION ◽  
10.5006/2451 ◽  
2017 ◽  
Vol 74 (1) ◽  
pp. 66-74 ◽  
Author(s):  
L.M. Zhang ◽  
A.L. Ma ◽  
H.X. Hu ◽  
Y.G. Zheng ◽  
B.J. Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Photoelectron Spectroscopy ◽  
Amorphous Alloys ◽  
Diffusion Mechanism ◽  
High Surface ◽  
Control Sample ◽  
Surface Concentration ◽  
Passive Films ◽  
High Surface Concentration

The effect of microalloying with Ti or Cr on the corrosion behavior of Al-Ni-Y amorphous alloys in 0.1 M NaCl solution was studied by potentiodynamic polarization, Mott-Schottky, and x-ray photoelectron spectroscopy techniques. Microalloying with Ti or Cr could greatly improve the corrosion resistance of Al-Ni-Y amorphous alloys. A high surface concentration of Ti or Cr in the passive films was detected, which should be responsible for the improved corrosion resistance compared to the control sample. The possible process of Ti or Cr involved in the passive films was proposed in terms of the point defect model and the vacancy diffusion mechanism. Furthermore, the effect of Ti was stronger than Cr because of the higher film resistance as well as the higher surface concentration. The different passivation abilities and atomic radiuses between Ti and Cr were presented to explain the better microalloying effect of Ti compared to Cr.

Study of Oxygen Diffusion in Polycrystalline ZnO by SIMS

2009 ◽  
Vol 289-292 ◽  
pp. 523-530
Author(s):  
Antônio Claret Soares Sabioni ◽  
Antônio Márcio J.M. Daniel ◽  
Anne Marie Huntz ◽  
Wilmar Barbosa Ferraz ◽  
François Jomard
Keyword(s):  
Grain Boundary ◽  
Oxygen Pressure ◽  
Diffusion Coefficients ◽  
Effective Charge ◽  
Oxygen Diffusion ◽  
Secondary Ion Mass Spectrometry ◽  
Diffusion Mechanism ◽  
Bulk Diffusion ◽  
Interstitial Oxygen ◽  
Exchange Method

Oxygen diffusion coefficients were measured in polycrystalline ZnO by means of the gas-solid exchange method using the isotope 18O as the oxygen tracer. The diffusion annealings were performed at 892oC and 992oC, in an Ar+18O2 atmosphere under oxygen partial pressures from 0.1 to 1atm. After the diffusion annealings, the 18O diffusion profiles were established by secondary ion mass spectrometry (SIMS). Increasing the oxygen pressure leads to an increase of the oxygen diffusion in ZnO. The bulk diffusion coefficients depends on oxygen pressure according to , at 882oC, or , at 992oC, which indicates that the oxygen bulk diffusion mechanism should preferentially take place by means of interstitial oxygen having a null effective charge. The grain boundary diffusion coefficients show little dependence on oxygen pressure at 882oC, given by , which should correspond to a diffusion mechanism by means of interstitial oxygen, with a double negative charge, but at 992oC this dependence is corresponding to a diffusion mechanism by interstitial oxygen having a null effective charge. The results also show that the grain boundary is a fast path for the oxygen diffusion in polycrystalline ZnO.

Carbon formation and gasification on metals. Bulk diffusion mechanism: A reassessment

2011 ◽  
Vol 178 (1) ◽  
pp. 110-116 ◽  
Author(s):  
L.S. Lobo ◽  
J.L. Figueiredo ◽  
C.A. Bernardo
Keyword(s):  
Diffusion Mechanism ◽  
Bulk Diffusion ◽  
Carbon Formation
Sign in / Sign up

Export Citation Format

Share Document