Dissolution Rate Constants Research Articles

The Dissolution Mechanism of Copper Weld Brazing with Cu-Based Brazing Alloys

In this paper, the dissolution mechanism of copper weld brazing has been researched. The thickness losses of Cu foil in contact with molten Cu-P and Cu-Ag binary alloys at different temperatures have been studied. And the dissolution rate constants in both alloys is calculated and exists following relation: kCu-P(T)=10kCu-Ag(T), which explains the special phenomenon that the dissolving amount of copper in Cu-P liquid alloys is larger than that in Cu-Ag liquid alloys by using weld brazing technology. The dissolution rate of copper in filler metals is the main reason to realize weld brazing. It can be concluded that element P is indispensable in filler metals as the function of accelerating dissolution during weld brazing.

Dissolution behavior of Cu in Cu-Ag and Cu-P brazing alloys using weld brazing

The dissolution behavior of base metal Cu in the Cu-Ag and Cu-P brazing alloys using weld brazing was researched. The thickness loss of Cu foil in contact with Cu-P and Cu-Ag alloys at 800–920°C was measured. And the dissolution rate constants in both alloys were calculated as the following relation: k Cu-P( T)=10 k Cu-Ag( T), which explains the special phenomenon that the dissolving amount of copper in Cu-P liquid alloys is larger than that in Cu-Ag alloys under the same condition. As weld brazing has its own characteristics of short reaction time and quick temperature variation in one thermal cycle, the quick dissolution rate of copper in filler metals is the main reason to achieve weld brazing. It can be concluded that element P is indispensable in filler metals compared with element Ag as the function of accelerating dissolution during weld brazing. Finally, the influences of the addition of alloy element on mechanical performance of the welding joints were studied and the design principles of filler metals for weld brazing were proposed to achieve good mechanical performance.

The major ion, δ 44/40Ca, δ 44/42Ca, and δ 26/24Mg geochemistry of granite weathering at pH = 1 and T = 25 °C: power-law processes and the relative reactivity of minerals

We dissolved Boulder Creek Granodiorite in a plug flow reactor for 5794 h at pH = 1 and T = 25 °C. The primary purpose of the experiment was to identify controls on dissolved δ 44/40Ca, δ 44/42Ca, and δ 26/24Mg values during granite weathering. Herein, we also examine the origin of Ca and Mg isotopic variability among minerals composing the Boulder Creek Granodiorite, and we constrain fundamental characteristics of granite weathering important for quantifying the elemental and isotopic geochemistry of the reactor output. Nine Ca-bearing minerals display an 8.80‰ range of δ 44/40Ca values and a 0.51‰ range of δ 44/42Ca values. Three Mg-bearing minerals display a 1.53‰ range of δ 26/24Mg values. These ranges expressed at the mineralogical scale are higher than the ranges thus far reported for bulk igneous rocks. Most of the δ 44/40Ca variability reflects 40Ca enrichment in K-feldspar, and to a lesser extent, biotite, due to the radioactive decay of 40K over the 1.7 Ga age of the rock, whereas the entire range of δ 44/42Ca values reflects mass-dependent isotope fractionation during igneous differentiation and crystallization. The range of δ 26/24Mg values may represent either fractionation during the chloritization of biotite or interaction of the Boulder Creek Granodiorite with Mg-rich metamorphic fluids having low δ 26/24Mg values. The elemental and isotopic composition of the reactor output varied substantially during the experiment. We synthesize the mineralogical and fluid data using coupled mass-conservation equations solved at non-steady-state. Model calculations reveal an intricate balance between increasing specific surface area and decreasing mineral concentrations. While surface area normalized dissolution rate constants were time-invariant, specific surface area increased as a power-law function of time through positive feedbacks between mechanical disaggregation, chemical dissolution, and mineral depletion. Variations in dissolved δ 44/40Ca, δ 44/42Ca, and δ 26/24Mg values reflect conservative mixing rather than fractionation. Apatite and calcite initially control δ 44/40Ca and δ 44/42Ca values, followed by biotite, titanite, epidote, hornblende, and plagioclase. The release of radiogenic 40Ca clearly defines the period where biotite dissolution dominates. The brucite layer of chlorite initially controls δ 26/24Mg values, followed by biotite, the TOT layer of chlorite, and hornblende. Through direct isotopic tracking, these results demonstrate that trace minerals, such as apatite and calcite in the case of Ca and brucite in the case of Mg, dominate elemental release during the incipient stages of granite weathering. The results further show that biotite dissolution dominates the middle stages of granite weathering and that plagioclase dissolution only becomes important during relatively late stages. The Ca and Mg isotope variations associated with these stages are distinct and potentially resolvable in soil mineral weathering studies.

Counter-intuitive enhancement in the dissolution of indomethacin with the incorporation of cohesive poorly water-soluble inorganic salt additives

The objective of this work was to investigate the influence of various micronized poorly water-soluble inorganic materials on the dissolution and de-agglomeration behaviour of a micronized, poorly water-soluble model drug, indomethacin, from lactose interactive mixtures. Dissolution of indomethacin was studied using the USP paddle method and the data were modelled with multi-exponential equations using a nonlinear least squares algorithm in order to obtain key parameter estimates. The dispersion of indomethacin mixtures was measured by laser diffraction. The addition of aluminium hydroxide and calcium phosphate to binary mixtures of indomethacin counter-intuitively improved the dissolution rate of indomethacin due to significant increases in both the estimated initial concentration and dissolution rate constant of dispersed particles of indomethacin. While some enhancement was due to pH changes in the dissolution medium, the presence of these poorly water-soluble inorganic salts caused de-agglomeration. Average particle size distributions indicated that the presence of aluminium hydroxide within the matrix of indomethacin had reduced the agglomerate concentration whilst increasing the dispersed particle concentration. These findings provide the first evidence of the ability of poorly water-soluble inorganic salts to enhance the de-agglomeration and dissolution of micronized powders, potentially translating to improved bioavailability of poorly water-soluble drugs.

Effects of hardness on the disintegration time and the dissolution rate of uncoated caffeine tablets

The effects of hardness on disintegration and dissolution characteristics of uncoated caffeine tablets made at eight different pressure levels were studied. The disintegration times were determined using the J.P. VIII procedure with disks and the dissolution rate measurements were performed with the U.S.P.XVIII procedure (U.S.P. method) and the J.P. VIII disintegration test apparatus (J.P. method). A good correlation between the hardness and the disintegration times was obtained. The dissolution rate constants were determined from the equation of Noyes & Whitney (1897) and a good correlation between the hardness and the dissolution rate constants was obtained. The hardness governed the dissolution over all the stages from tablet to the smallest particles after the breakage by disintegration. The dissolution rates of the J.P. method were greater than those of the U.S.P. method.

Interpretation of dissolution rate data from in vitro testing of compressed tablets.

To find if theoretically and experimentally a relation existed between the dissolution rate theory of Kitazawa, Johno & others (1975) and that of Wagner (1969), a study was undertaken with uncoated caffeine, aspirin and proxyphylline tablets using two dissolution methods. Although the original treatment for surface area of drug available for dissolution was quite different between the two dissolution theories, the dissolution rate constants obtained were in fair agreement. Hence it might not be always necessary to take into consideration changes in the surface area as a function of dissolution rate, and the 1n W infinity/(W infinity) versus time plot devised by Kitazawa & others might be a useful and simple means of obtaining the dissolution rate constant of an active ingredient from a dosage form such as compressed tablet.

The influence of solution viscosity on the dissolution rate of soluble salts, and the measurement of an "effective" viscosity.

Abstract The rate of solution of KCl and NaCl from compressed discs has been determined under controlled conditions, in water at 25° and in solutions of varying concentrations of polyvinylpyrrolidone (molecular weight 360 000), polyoxyethylene glycol 6000 and cetomacrogol 1000. Dissolution rate constants decrease with increasing bulk solution viscosity, as expected, but no one equation relating rate constant and bulk viscosity fits the results for the systems studied. Calculation of an effective viscosity from the diffusion coefficients of the salts in water and the diffusion coefficients of the salt in the polymer solutions enables an empirical correlation of the results to be made. The relation of the effective viscosity to the microscopic viscosity is discussed in an Appendix.

Transdermal Delivery of Verapamil Using Mixed Grades of Eudragit: Design, In-vitro and In-vivo Evaluation

A matrix-dispersion-type transdermal drug delivery system of verapamil was designed and developed using different ratios of mixed polymeric grades of Eudragit. Formulations were selected on the basis of their drug release content and release pattern. These were evaluated for in-vitro dissolution characteristics using a Cygnus sandwich patch holder. The release followed Higuchi kinetics (r = 0.972-0.996; P < 0.001). In-vivo evaluation was carried out on healthy human volunteers (24.00 ± 0.82 y; 60.58 ± 6.29 kg). In-vitro dissolution rate constant (K) and pharmacokinetic parameters generated from plasma and urine were evaluated by two-way analysis of variance. Statistically excellent correlation was found between percentage of drug absorbed from patch vs Cmax, AUC0-24, AUC0-∞. The time at which maximum lowering of blood pressure was found coincided with the tmax. A highly significant difference (P < 0.001) was observed when Cmax and AUC0-∞ generated from plasma and urine data were compared but when k, t½e, ka, t½a were compared, the differences were not significant. We conclude that urinary excretion data may be used as a simpler alternative to blood level data in studying the kinetics of absorption.

Acid volatile sulfides oxidation and metals (Mn, Zn) release upon sediment resuspension: Laboratory experiment and model development

Sediment from the Anacostia River (Washington, DC, USA) was suspended in aerobic artificial river water for 14 d to investigate the dynamics of dissolved metals release and related parameters including pH, acid volatile sulfides (AVS), and dissolved/solid phase Fe(2+). To better understand and predict the underlying processes, a mathematical model is developed considering oxidation of reduced species, dissolution of minerals, pH changes, and pH-dependent metals' sorption to sediment. Oxidation rate constants of elemental sulfur and zinc sulfide, and a dissolution rate constant of carbonate minerals, were adjusted to fit observations. The proposed model and parameters were then applied, without further calibration, to literature-reported experimental observations of resuspension in an acid sulfate soil collected in a coastal flood plain. The model provided a good description of the dynamics of AVS, Fe(2+), S(0)((s)), pH, dissolved carbonates concentrations, and the release of Ca((aq)), Mg((aq)), and Zn((aq)) in both sediments. Accurate predictions of Mn((aq)) release required adjustment of sorption partitioning coefficient, presumably due to the presence of Mn scavenging by phases not accounted for in the model. The oxidation of AVS (and the resulting release of sulfide-bound metals) was consistent with a two-step process, a relatively rapid AVS oxidation to elemental sulfur (S(0)((s))) and a slow oxidation of S(0)((s)) to SO(4)(2-)((aq)), with an associated decrease in pH from neutral to acidic conditions. This acidification was the dominant factor for the release of metals into the aqueous phase.

Effect of Addition of Ammonium Compounds on the Dissolution Rate of a South African Magnesium-Based Material

High dissolution rates provide better alkalinity that is important for sulphur dioxide (SO2) absorption. Therefore the rate at which magnesite dissolves is very important in wet flue gas desulphurisation process (FGD). In this study, we investigated the use of ammonium compounds for enhancing the dissolution rate of magnesium-based compounds. The dissolution rates were determined by using the shrinking core model (SCM) with surface control, i.e, [1 − (1 − X)1/3] = krt. The dissolution characteristics were investigated under the following conditions by using the pH-Stat method: temperature, 60°C; pH, 5; stirrer speed, 200 rpm; particle size 45 μm. The addition of ammonium compounds helps improve the dissolution rate of magnesium-based compounds. Upon the addition of 0.5 g of ammonium nitrate, the dissolution rate constants increased by 122%. The dissolution reaction conformed to the SCM, and chemical reaction control was the rate-controlling step.

Basalt and olivine dissolution under cold, salty, and acidic conditions: What can we learn about recent aqueous weathering on Mars?

To test which variables may be important for weathering on Mars, the effects of temperature (22°C, 6°C, and −19°C), high ionic strength, and oxygen concentrations were investigated in batch dissolution experiments containing forsterite, fayalite, and basalt glass. CaCl2‐NaCl‐H2O brine can remain liquid to temperatures of −55°C and thus may be liquid in the cold, dry climate that currently characterizes Mars. To understand weathering under such conditions, dissolution rates were measured in experiments in distilled water with and without CaCl2 and NaCl. As observed by others, dissolution rates increased with temperature, and only fayalite dissolution was significantly affected by the presence or absence of oxygen. Enhanced fayalite dissolution under anoxic conditions suggests that Fe‐rich olivine would dissolve more rapidly than Mg‐rich olivine on Mars. Dissolution in the two most dilute experimental solutions (deionized water and CaCl2‐NaCl‐H2O solution of ionic strength = 0.7 m) were the same within uncertainty, but apparent dissolution rate constants in CaCl2‐NaCl‐H2O brines were significantly slower. Steady silica concentrations are decreased in the brines, consistent with other work, and precipitation rates of silica decrease with decreasing temperatures. These results suggest that enhanced silica precipitation could be an indicator of high ionic strength solutions on Mars. Consistent with these observations, weathering of basalt has been observed to sometimes be accompanied by precipitated layers of silica in cold, dry environments on Earth. If dissolution on Mars occurs or occurred under conditions similar to our experiments, cation leaching would be expected to be accompanied by silica precipitates on weathering surfaces.

Release of Beryllium from Beryllium-Containing Materials in Artificial Skin Surface Film Liquids

Skin exposure to soluble beryllium compounds causes systemic sensitization in humans. Penetration of poorly soluble particles through intact skin has been proposed as a mechanism for beryllium sensitization; however, this mechanism is controversial. The purpose of this study was to investigate the hypothesis that particulate beryllium compounds in contact with skin surface release ions via dissolution in sweat. Dissolution of 11 particulate beryllium materials (hydroxide, metal, oxides and copper-beryllium fume), 3 copper-beryllium alloy reference materials (chips and solid block), and 4 copper-beryllium alloy tools was measured over 7 days in artificial sweat buffered to pH 5.3 and pH 6.5. All test materials released beryllium ions in artificial sweat. Particulate from a reduction furnace that contained both crystalline and amorphous beryllium was the most soluble compound-40% dissolved in 8 h. Rates of beryllium release from all other particulate and reference materials were faster at pH 5.3 than at pH 6.5 (P < 0.05). At pH 5.3, values of the chemical dissolution rate constant, k [g (cm² day)⁻¹] differed significantly for hydroxide, metal, and oxide -1.7 ± 0.0 × 10⁻⁷, 1.7 ± 0.6 × 10⁻⁸, and 1.0 ± 0.5 × 10⁻⁹, respectively (P < 0.05). Up to 30 μg of beryllium was released from the alloy tools within 1 h. Dissolution rates in artificial sweat were equal to or faster than values previously determined for these materials in lung models. Poorly soluble beryllium materials undergo dissolution in artificial sweat, suggesting that skin exposure is a biologically plausible pathway for development of sensitization. Skin surface acidity, which is regulated by sweat chemistry and bacterial hydrolysis of sebum lipids varies by anatomical region and may be an exposure-modifying factor for beryllium particle dissolution.

Investigation of Nanoparticles Occurring in the Colloidal Silicalite-1 Zeolite Crystallization Process Using Dissolution Experiments

In concentrated clear sol prepared from tetraethylorthosilicate, tetrapropylammonium hydroxide, and water suitable for crystallization of Silicalite-1 zeolite, the main part of the silica is present in nanoparticles. The nature of these nanoparticles and their evolution during the induction period and the stage of early crystal growth was investigated via dissolution experiments in the presence of excess TPAOH. The dissolution process was monitored in situ using static and dynamic light scattering (SLS/DLS) and synchrotron small-angle X-ray scattering (SAXS). The complete dissolution of an individual nanoparticle was observed to occur in one step. Dissolution transformed a nanoparticle into a cluster of silicate oligomers. Larger grown nanoparticles dissolved slower. Exponential dissolution rate constants scaled inversely proportional with the volume of the nanoparticle’s silica core. This experimentally observed dissolution behavior was modeled by assuming that a nanoparticle dissolved to oligomers via a...

The influence of aggregate microenvironment on the dissolution of oxazepam in ternary surfactant interactive mixtures.

The purpose of this research was to test the hypothesis that the dissolution rate of oxazepam in interactive mixtures was dependent on the influence of surfactant within the microenvironment of mixed oxazepam-surfactant aggegrates produced during dissolution. The studies utilised both powder and intrinsic dissolution methodology; spectrophotometric assays were developed and validated and dissolution data were modelled using multi-exponential equations and dissolution rate constants estimated using non-linear least squares algorithms. For a series of water-soluble ternary additives to the oxazepam interactive mixture, sodium lauryl sulfate and cetrimide were shown not only to decrease aggregation through enhanced dispersion, but also to increase the dissolution rate constant. Such an increase in dissolution rate constant was observed in the intrinsic dissolution studies when surfactant concentrations exceeded the critical micelle concentration and the oxazepam solubility increased. Laser diffraction particle sizing during the dissolution process confirmed the presence of dispersed particles and aggregates and demonstrated that the presence of surfactant improved the state of dispersion. The results of studies using different rotational speeds produced unexpected increases in aggregation and decreases in dissolution rate constants at about 150 rev min(-1), consistent with the transient formation of loose aggregates containing dissolved surfactant.

Sensitivity of dissolution rate to location in the paddle dissolution apparatus.

The aim of the present study was to determine the apparent diffusion boundary layer and dissolution rate constant for various surfaces of compacts and at various locations in the USP paddle dissolution apparatus. Benzoic acid compacts were coated with paraffin wax leaving only the surface under investigation free for dissolution. The dissolution rates for various surfaces at varying locations in the paddle dissolution vessel were determined from the slope of the dissolution profile (amount dissolved (mg) versus time (min)). The apparent diffusion boundary layer and dissolution rate constant were calculated and were found to vary depending on the surface of the compact from which dissolution took place and also on the location and size of the compact. It may be concluded that, in developing models to describe the dissolution from solid dosage forms, it is not accurate to assume constant hydrodynamics and mass transfer rates at all surfaces of the system, or in different locations within the test device. A more exact description of the hydrodynamics would be necessary in order to precisely model drug dissolution in the paddle dissolution apparatus.

Controlled transdermal delivery of propranolol using HPMC matrices: design and in-vitro and in-vivo evaluation.

To improve bioavailability and achieve a smoother plasma-concentration profile as compared with oral administration, a matrix-dispersion-type transdermal delivery system was designed and developed for propranolol using different ratios of hydroxypropylmethylcellulose (HPMC) K4M, K15M and K100M. Formulations were evaluated for in-vitro dissolution characteristics using a Cygnus' sandwich-patch holder. Drug release followed Higuchi rather than zero-order or first-order kinetics. In-vivo evaluation was carried out on healthy volunteers (21+/-1.41 years; 60.89+/-5.35 kg) following the balanced incomplete block design. The dissolution rate constant (k) and data generated from plasma and urine (Cmax, maximum plasma concentration; t(max), time to reach peak plasma concentration; AUC, area under the curve; k(e), elimination rate constant; t1/2e, elimination half-life; k(a), absorption rate constant; t1/2a, absorption half-life) were evaluated statistically by two-way analysis of variance. Statistically excellent correlation was found between the percentage of drug absorbed and Cmax, AUC0-24 and AUC0-infinity. A highly significant difference (P < 0.001) was observed when Cmax and AUC0-infinity, generated from plasma and urine were compared, but k(e), t1/2e, k(a) and t1/2a did not differ significantly (P > 0.1). We conclude that urinary excretion data may be used as a simpler alternative to blood level data in studying the kinetics of absorption and deriving the absorption parameters.

The temperature dependence of feldspar dissolution determined using a coupled weathering–climate model for Holocene-aged loess soils

Soils developed over the last 10–13 ky on Peoria loess along a transect parallel to the Mississippi River spanning ∼ 1600 km from north to south were investigated to estimate the effects of climate on rates of chemical weathering. In the 22 soils, Na concentrations generally decreased from parent composition to the surface, defining depletion profiles that document the weathering of plagioclase. The integrated fraction of Na ( f) dissolved from each profile varied from ∼ 0 in the north to 26% in the south. This variation is attributed to an increase in average precipitation and temperature from the north (today's average values: 0.5 m/y, 7.5 °C) to the south (1.2 m/y, 20.3 °C). We used the output from the GENESIS v2 Global Climate Model (GCM) to calculate the mean annual temperature, precipitation, and porefluid advection velocity, v, through the soils for three time points during the last 13,000 y in order to quantify the effect of temperature on Na depletion. To interpret the soils quantitatively, the Na concentration-depth profiles were fit to a sigmoidal model equation that yielded three fit parameters: ( i) a lumped kinetic parameter related to the reaction front thickness ( K), ( ii) the Na concentration in soil at the surface ( C z = 0 ), and ( iii) the Na concentration at depth in the parent ( C o ). The product Kv, the fraction f, and the concentration difference, C o − C z = 0 , were all observed to vary with temperature along the transect. According to the derivation and assumptions of the sigmoidal model, these values are all functionally related to the dissolution rate constant of albite. The variation in temperature can be explained for Kv and ( C o − C z = 0 ) based on laboratory values of the activation energy, E a , for albite dissolution. In contrast, for the case of f, the temperature dependence is larger than E a because it incorporates contributions from both E a and the reaction enthalpy, ΔH, of albite dissolution. Furthermore, the temperature dependence determined from C o − C z = 0 yields the best estimate of activation energy for albite dissolution, E a = 75 ± 14 kJ/mol, because it is not dependent upon the assumptions of soil texture. Such quantitative interpretations of soil profiles will be useful in predicting the effects of climate on soil chemistry.

Oxidative Dissolution of Silver Nanoparticles by Biologically Relevant Oxidants: A Kinetic and Mechanistic Study

The oxidative dissolution of silver nanoparticles (AgNPs) plays an important role in the synthesis of well-defined nanostructured materials, and may be responsible for their activities in biological systems. In this study, we use stopped-flow spectrophotometry to investigate the kinetics and mechanism of the oxidative dissolution of AgNPs by H(2)O(2) in quasi-physiological conditions. Our results show that the reaction is first order with respect to both [Ag(0)] and [H(2)O(2)], and parallel pathways that involve the oxidation of H(2)O(2) and HO(2)(-) are proposed. The order of the reaction is independent of the size of the AgNPs (approximately 5-20 nm). The rate of dissolution increases with increasing pH from 6.0 to 8.5. At 298 K and I=0.1 M, the value of k(b) is five orders of magnitude higher than that of k(a) (where k(a) and k(b) are the rate constants for the oxidative dissolution of AgNPs by H(2)O(2) and HO(2)(-), respectively). In addition, the effects of surface coating and the presence of halide ions on the dissolution rates are investigated. A possible mechanism for the oxidative dissolution of AgNPs by H(2)O(2) is proposed. We further demonstrate that the toxicities of AgNPs in both bacteria and mammalian cells are enhanced in the presence of H(2)O(2), thereby highlighting the biological relevance of investigating the oxidative dissolution of AgNPs.

Comparative in vitro dissolution assessment of soluble and plain brands of aspirin tablets marketed in Nigeria

The in vitro dissolution profiles of four commercial brands of aspirin tablets (one soluble brand of aspirin, A1, and three plain brands of aspirin labeled A2-A4) were assessed using the USP XXI dissolution method. Various dissolution parameters such as percent dissolution in 30 min, dissolution rate constant (k), and time for 50% dissolution (DT50%) were obtained. The results indicate that A1 (the soluble aspirin brand) exhibited the highest dissolution profile while brand A3 had the least dissolution profile. The relative ranking in terms of percent dissolution in 30 min and dissolution rate constant (K) are in the order of A1>A4>A2>A3, while the ranking of time for 50% dissolution (DT50%) is in the reverse order of A1 0.05) among all the brands. They all indicated similar statistical behaviour in terms of their dissolution profiles. Keywords: Aspirin, dissolution profile, Nigeria.

Interfacial interaction of solid cobalt with liquid Pb-free Sn–Bi–In–Zn–Sb soldering alloys

Dissolution kinetics of cobalt in liquid 87.5%Sn–7.5%Bi–3%In–1%Zn–1%Sb and 80%Sn–15%Bi–3%In–1%Zn–1%Sb soldering alloys and phase formation at the cobalt–solder interface have been investigated in the temperature range of 250–450 °C. The temperature dependence of the cobalt solubility in soldering alloys was found to obey a relation of the Arrhenius type cs = 4.06 × 102 exp (−46300/RT) mass% for the former alloy and cs = 5.46 × 102 exp (−49200/RT) mass% for the latter, where R is in J mol−1 K−1 and T in K. For tin, the appropriate equation is cs = 4.08 × 102 exp (−45200/RT) mass%. The dissolution rate constants are rather close for these soldering alloys and vary in the range (1–9) × 10−5 m s−1 at disc rotational speeds of 6.45–82.4 rad s−1. For both alloys, the CoSn3 intermetallic layer is formed at the interface of cobalt and the saturated or undersaturated solder melt at 250 °C and dipping times up to 1800 s, whereas the CoSn2 intermetallic layer occurs at higher temperatures of 300–450 °C. Formation of an additional intermetallic layer (around 1.5 μm thick) of the CoSn compound was only observed at 450 °C and a dipping time of 1800 s. A simple mathematical equation is proposed to evaluate the intermetallic-layer thickness in the case of undersaturated melts. The tensile strength of the cobalt-to-solder joints is 95–107 MPa, with the relative elongation being 2.0–2.6%.