January 2021
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7 Reads
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January 2021
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7 Reads
October 2013
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25 Reads
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4 Citations
Metalurgija
Problems of reactive diffusion at the interface solid phase - melt were studied theoretically and experimentally. A theoretical description of the kinetics of dissolution of the solid phase in the melt is presented for the case of planar dissolution. The main intention was to study experimentally the copper dissolution in melts of various solder alloys and the related reactive diffusion. We used pure Sn and Sn-Cu, Sn-Ag-Cu, Sn-Sb, Sn-Zn alloys as solder materials. Experiments aimed at the study of a Cu plate dissolving in the solder melt were carried out at various conditions. Concentration profiles of elements and thickness of layers of phases were determined by SEM and X-ray microanalyses (WDX, EDX) of specimens after their heating.
March 2012
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13 Reads
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3 Citations
Problems of reactive diffusion at the solid phase and melt contact are studied theoretically. The rate constant is a fundamental parameter characterizing the dissolving rate at a certain configuration of experiment. Relationships between the solid phase dissolving rate, i.e. the solid phase interface boundary movement in the melt, and rates of growth of intermetallic phases in the metal (Cu) are observed. This procedure enables the creation of surface and subsurface layers of regulated thickness in metallic materials by means of reactive diffusion. The main intention was an experimental study of copper dissolving in melts of various solder alloys and the related reactive diffusion. We used Sn, SnCu, SnAgCu, SnZn and SnIn alloys as a solder material. The problems that need to be solved preferentially are emphasized. It concerns especially the determination of the rate constant of dissolving and verifying whether the proposed model equations can be used for this constant determination in cases of cylindrical and planar dissolving. Rapid growth of phases in the metal (Cu) and determination of the thickness of layers with these phases pose considerable time demands to X-ray microanalyses (WDX, EDX, BSE, SEM) of specimens after their long-time heating.
April 2011
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9 Reads
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2 Citations
Problems of reactive diffusion at the solid phase and melt contact were studied theoretically and experimentally. The main intention was to calculate the time course of the solid phase dissolving in the case of cylindrical dissolving. These calculations were carried out on the assumption for the rate constant of dissolving K = const. In our work we give heed especially to the dominating process, which is the solid metal A dissolved in the melt B. During the dissolving the melt B saturates with the metal A and the process is influenced by convections which are characteristic for the given experimental configuration. A theoretical description of the kinetics of the solid phase dissolving in the melt will be presented for the case of cylindrical dissolving. The aim is to derive a relation for the interface boundary movement c(t) in dependence on time and a time course of growth of the element A concentration in the melt B. There are problems with accurate determination of the interface boundary movement after certain heating times of specimens, when it is observed experimentally, since intermetallic phases create in the original A metal at both the diffusion and cooling and some phases segregate at the solidifying melt cooling. The main intention was an experimental study of the copper dissolving in the tin melt. Experiments aimed to the determination of the Cu wires (diameters from 0.5 to 3.5 mm) dissolution in the solder melt were carried out at various selected temperatures and times. Rapid growth of phases in the metal A and determination of the thickness of layers with these phases pose considerable time demands to X-ray micro-analyses (WDX, EDX) of specimens after their longtime heating.
March 2011
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8 Reads
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2 Citations
Problems of reactive diffusion at a solid phase - melt contact were studied theoretically. The main intention was to calculate the time course of the solid phase dissolving in the case of planar dissolving. In our work we give heed especially to the dominating process, which is the solid metal A dissolving in solder melt B. During the dissolving, melt B saturates with metal A, and the process is influenced by convections which are characteristic for a given experimental configuration. A theoretical description of the kinetics of solid phase dissolving in the melt will be presented for the case of planar dissolving. The aim is to derive a relation for the interphase boundary movement (t) depending on time and a time course of growth of the element A concentration in the melt B. There are difficulties in accurate determination of the interphase boundary movement after heating of specimens for certain time intervals. It should be performed experimentally, since intermetallic phases are formed in original metal A both via diffusion and upon cooling and some phases segregate upon cooling of the solidifying melt. The main intention was to study experimentally the copper dissolving in melts of various solder alloys and the related reactive diffusion. We used pure Sn and Sn-Cu, Sn-Ag-Cu, Sn-Sb, Sn-Zn alloys as solder materials. Experiments aimed at the study of a Cu plate dissolving in the solder melt were carried out at various selected temperatures and times. The problems of reactive diffusion were studied both theoretically and experimentally and the problems that have to be solved preferably were emphasized. Concentration profiles of elements and thickness of layers of phases can be determined with SEM and X-ray microanalyses (WDX, EDX) of specimens after their diffusion heating.
April 2010
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7 Reads
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2 Citations
In this work we give heed especially to the dominating process which is the solid metal A dissolving in the melt B. During the dissolving, the melt B saturates with the metal A and the process is influenced by convections which are characteristic for the given experimental configuration. A theoretical description of the kinetics of the solid phase dissolving in melt will be presented for the case of planar and cylindrical dissolving. The aim is to derive a relation for the interface boundary x(t) movement in dependence on time and a time course of growth of the element A concentration in the melt B. There are problems with an accurate determination of the interface boundary movement after certain heating times of specimens, when it is observed experimentally, since intermetallic phases create in the original A metal at both the diffusion and cooling and some phases segregate at the solidifying melt cooling. The rate constant is a fundamental parameter characterizing the dissolving rate at a certain configuration. We present a theoretical description of dissolving of a long metallic cylinder submerged into a melt column and relations for the rate constant determination from the time of the whole metallic cylinder dissolution are derived. In our experiments were performed in which Cu was dissolving in the Sn melt for a Cu cylinder (wire) diameters 0.8 divided by 2.5 mm and the rate constant K (T = 350 degrees C) was determined. Relationships between the solid phase dissolving rate, i.e. the solid phase interface boundary movement x(t) in the melt and rates of growth of intermetallic phases in the metal A will be observed. This procedure enables to create surface and subsurface layers of regulated thickness in metallic materials by means of reactive diffusion.
March 2010
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12 Reads
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1 Citation
Mathematics and Computers in Simulation
The solution of the diffusion equation at the non-stationary boundary represents the so-called Stefan problem which can be solved by means of the thermal potential of a double-layer with the accuracy sufficient for description of diffusion phenomena. The results were methods for determination of the mean values of the interdiffusion coefficients. The interface boundary shift and diffusivity in the diffusion joints can be determined very precisely from the areas below and above the concentration curve. The diffusivities in the Ni/Ni-Al and Fe/Fe-Mn diffusion joints were calculated from the experimental data using the balance equations that express the law of conservation of the diffusing material in the specimens and on the interface boundary. A new computer program (in Matlab) for the simulation of diffusion processes has been developed.
March 2009
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8 Reads
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1 Citation
When developing new types of materials with special properties for the automotive industry, steels with high content of manganese (up to 25 wt. % Mn) were studied. These steels embody increased failure resistance, high level of deformation hardening, plastic response and high value of energy absorption in crash situations [1,2]. The aim of our work was to study an interaction of a FeMn alloy with pure iron from the view of diffusion processes. For that purpose, diffusion joints Fe/FeMn-steel were created and long-term heated at the temperatures of 800, 900 and 1050 °C. Dependences of diffusivities of Mn on its concentration were calculated from concentration profiles of manganese after diffusion heating applying three analytical methods. In the first method, constant values of diffusivities Di, i = 1,2 for both Fe and steel were taken into account. In the second case a modified Matano-Boltzmann method utilizing polynomials was applied, which simplifies solution in numerous cases. The third method performs the solution of the non-linear equation of diffusion on the assumption of a linear dependence of diffusivity on concentration applying a procedure based on perturbation calculus. The results of the solution will be graphically documented in details together with the description of experiments.
March 2007
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55 Reads
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4 Citations
Interaction of lead-free solders with copper substrate represents an important phenomenon in the issue of reliability of solder joints. New experimental data describing phase equilibria in the Cu-In-Sn system after long-time diffusion annealing at the 400°C/50 hours, 600 °C/310 hours and 600°C/48 hours will be presented. The composition of solders was: 100% Sn, 75 % Sn + 25 % In, 50 % Sn + 50 % In, 25 % Sn + 75 % In, 100 % In. The fast quenching method was employed to freeze thermodynamic equilibrium after annealing, followed by metallography, microhardness measurements, SEM (Scanning Electron Microscope) and WDX (Wave Dispersive X-ray) analysis. New phase equilibrium data, together with the data from literature, represent the best existing experimental description of phase equilibria in the system in question. The obtained experimental results of the phase equilibria were compared with the thermodynamic modelling by the CALPHAD (Calculation of Phase Diagrams) method and with other authors.
January 2007
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24 Reads
a) Vysoká škola báňská – Technická Univerzita Ostrava, FMMI, katedra neželezných kovů, rafinace a recyklace, 708 33 Ostrava -Poruba, ČR, E-mail: Jaromír.Drapala@vsb.cz b) Na Čtvrti 14, 705 00 Ostrava – Hrabůvka, ČR c) Masarykova univerzita, Katedra.teoretické a fyzikální.chemie, Kotlářská 2, 611 37 Brno Abstrakt V rámci řešení evropského projektu COST Action 531 "Lead-free Solder Materials" bylo provedeno experimentální studium ternárního systému Cu-In-Sn. Byla aplikována metoda reaktivní difuze pomocí difuzních dvojic Cu/In-Sn s různými poměry In : Sn. Difuzní žíhání bylo prováděno při různých teplotách 400 a 600 °C, při různých časech a experimentálním uspořádání. Pomocí mikrostrukturní a liniové mikroanalýzy za použití metod EDX a WDX byly získány koncentrační profily přítomných prvků v oblasti difuzních spojů. Zjištěné koncentrační skoky, prezentující oblasti existence jednotlivých fází, umožní upřesnit fázový ternární diagram systému Cu-In-Sn. Získané experimentální výsledky budou konfrontovány s literárními údaji a s vlastními termodynamickými výpočty pomocí programu THERMOCALC. Abstract An experimental study of the Cu-In-Sn ternary system was performed in terms of the European project COST Action 531 "Lead-free Solder Materials". The method of reactive diffusion utilizing diffusion couples Cu/In-Sn with various In:Sn ratios was applied. Diffusion annealing was carried out at various temperatures 400 and 600 °C, at various times and experimental arrangements. Concentration profiles of the present elements in the area of diffusion joints were obtained by means of micro-structural and line microanalyses applying the EDX and WDX methods. The detected concentration jumps presenting the areas of existence of individual phases enable to make the ternary phase diagram of the Cu-In-Sn system more precise. The acquired experimental results will be confronted with literature data and with our thermodynamic calculations by means of the THERMOCALC program.
... With the development of electronics manufacturing and welding technology, it has been an inevitable trend that leadfree solder substitutes the lead-containing alloy (Li 2005;Katsuaki 2001;Drápala et al. 2013). Sn-based alloy is a new type of brazing materials due to its excellent performance (Lai et al. 2003;Suzuki et al. 2005;Sebo et al. 2013). ...
October 2013
Metalurgija
... The width of the creating phase depends on the concentration curve of each phase and its rate of growth [11]. Some our results at the study of the reactive diffusion were published in the journal Defect and Diffusion Forum [12][13][14][15] and [16]. ...
April 2011
... The width of the creating phase depends on the concentration curve of each phase and its rate of growth [11]. Some our results at the study of the reactive diffusion were published in the journal Defect and Diffusion Forum [12][13][14][15] and [16]. ...
March 2011
... The width of the creating phase depends on the concentration curve of each phase and its rate of growth [11]. Some our results at the study of the reactive diffusion were published in the journal Defect and Diffusion Forum [12][13][14][15] and [16]. ...
March 2012
... The width of the creating phase depends on the concentration curve of each phase and its rate of growth [11]. Some our results at the study of the reactive diffusion were published in the journal Defect and Diffusion Forum [12][13][14][15] and [16]. ...
April 2010
... Isothermal sections of the equilibrium phase diagram in the ternary Bi-Cu-Sn system were calculated using the CALPHAD method with Thermo-Calc Software and the COST531 thermodynamic database [28,29]. The results of the calculations at T = 473 K are shown in Fig. 5. ...
March 2007
... not less important were also the related articles about mechanic properties (which was one of favored of the Šatava's research topics [208,217]), diffusion studies [203][204][205][206][207][208][209][210][211][212] and early measurements of electrical and heat conductivity [202,[214][215][216][217] inserted into category Mechanical and transport properties [200][201][202][203][204][205][206][207][208][209][210][211][212][213][214][215][216]. the last category of Czechoslovak papers dealing with ta is labeled as History and nomenclature. it contains reviews of historical aspects of thermometry and thermodynamics [221][222][223][224][225][226][227] and associated nomenclature issues [219,220]. ...
June 1983
Thermochimica Acta
... The results are presented in Fig. 2. This TGA data at different heating rates can be used to determine the kinetic parameters (Kubicek and Lesko, 1979). ...
June 1979
Thermochimica Acta
... From the results of the present preliminary measurements c B (x,t) in the region where atoms B diffuse from phase β into metal A, see Fig. 3, the concentration profile cannot always be described by the function (31). If a new coordinate system with the origin x' = 0 is placed on axis 1 in Fig. 3, then the following function better corresponds to the measured concentration profiles: ...
March 2010
Mathematics and Computers in Simulation