Structure Of Intermetallic Compounds Research Articles

Highly dispersive Au nanoparticles on TiO2 nanofibers as a supported catalyst synthesized from Al-Ti-Au intermetallic compound

In the present study, we highly dispersed the Gold nanoparticles onto TiO2 nanofibers from leached Al-Ti-Au intermetallic compounds (IMCs) as a catalyst. The IMCs have an ordered structure, which could let the substitutional Au atoms neighboring to Ti atoms in IMC structure. The Al-based IMC single phase was proposed to obtain a high specific area and highly dispersive Au nanoparticles instead of the solid solution after leaching.Therefore, single phase L12-Al67Ti25Au8 was prepared and homogenized by arc-melting and conducted annealing. The ingot of L12-Al67Ti25Au8 was crushed and gathered under 25 µm as precursors. The leaching processes were using the aq. NaOH and aq. HCl. The removal Al of the precursors achieved 95%, and exhibits the special urchin-like particles with TiOx nanofibers. The urchin-like morphology provided a high surface area. After heat treatment, the TiOx transformed to the anatase TiO2 at 500 °C for 2 h under the air or CO/O2/He. The TEM images showed lots of Gold nanoparticles dispersing homogeneously onto the TiOx nanofibers. The CO conversion efficiency of Au/TiO2 was 50% at 50 °C without heat-treatment. Although the contribution mainly attributed to Au nanoparticles, Au/TiO2 exhibited significantly higher catalytic activity than Au/TiOx composite. The CO oxidation activity Au/TiO2 could reach up to 98% when as lower as 50 °C.

Crystal Chemistry of Lithium Intermetallic Compounds: A Survey

The structural chemistry of lithium intermetallic compounds that are formed in Li–М binary systems where М = Ca, Sr, Ba, Mg, Zn, Cd, and Hg is surveyed. It is for the first time that the crystal structures of intermetallic compounds are classified in terms of polyhedral precursor metal clusters (in the program package ToposPro). The precursor metal clusters of crystal structures are identified using the algorithms of partitioning structural graphs into cluster structures and via the design of the basal 3D network of the structure in the form of a graph whose nodes correspond to the positions of the centers of precursor clusters. Tetrahedral precursor metal clusters M4 are identified for the crystal structures LiZn3-oC4, LiMg3-hP2, LiCd3-hP2, LiHg3-hP8, (LiMg3)(Li2Mg2)-tI16, Li2Zn2-cF16, Li2Cd2-cF16, Li2Hg2-cP2, Li3Cd-cF4, and Li3Hg-cF16; tetrahedral metal clusters M4 are found for the framework structures with spacer atoms Sr(Li2Sr2)-tP20, Ca2(Li4)-cF24, and Ca2(Li4)-cP12; tetrahedral metal clusters M4 and rings M6, for framework structures Ba3Li2(Li10)-hP30 and Ba3Li2(Li4In6)-hP30; icosahedral metal clusters M13 for the framework structure Li(Zn13)-cF112; bilayer tetrahedral metal clusters 0@М4@M22 for the framework structure Li23Sr6-cF116; and deltahedra М17 and deltahedra М30, for framework structures Sr4Li14 [Sr(Sr4Li12)] [(Sr2 (Sr8Li18)]-tI252 and Ba4Li14 [Ba(Ba4Li12)][(Ba2 (Ba8Li18)]-tI252. The scenario of crystal structure self-assembly from precursor metal clusters S30 in intermetallic compounds is reconstituted as: primary chain S31→ microlayer S32→ microframework S33.

Protrusion friction stir spot welding: a simple novel method to produce dissimilar joints of galvanized steel/aluminum sheets with high mechanical performance

In this study, protrusion friction stir spot welding (PFSSW) as a simple novel method was applied using pinless tools and a specially designed protrusion on the surface of the backing anvil to weld aluminum and galvanized steel sheets with 1 mm thickness. Welding process was carried out at tool rotational speeds of 1600, 2000 and 2500 rpm and dwelling times of 3, 6 and 9 s. Microstructure and mechanical properties were used to evaluate the produced welds. The welds produced by PFSSW illustrated uniform and smooth surface appearance (free keyhole) with very low burs content compared to conventional FSSW due to the placing of the steel sheet on the aluminum sheet and presence of the protrusion. Completely metallurgical bonding and continuous structure of intermetallic compounds (IMCs) layer at the interface was obtained in the PFSSW. Dynamic recrystallization and presence of pearlite and non-equilibrium phases were main factors of the grain refining in the SZ while phases content increased with increase in the processing parameters. All the produced welds by PFSSW were failed by the CF mode and welding samples at 1600 rpm exhibited more peak load and failure energy than other conditions due to more joint width and lower IMCs layer thickness. The current process was able to produce dissimilar joints with superior mechanical performance compared to other techniques.

Surface segregation and alloying of immiscible Li-Cu and miscible Li-Pb nanoalloys investigated by basin-hopping Monte Carlo method

The configurations of immiscible Li-Cu and miscible Li-Pb nanoalloys are studied by the basin-hopping Monte Carlo method in cut-and-splice move and geometric center displacement operator. The atomic interactions are described by analytic embedded atom method. A Li-shell and Cu-core nanoparticle with fivefold symmetry is observed for the Li-Cu nanoalloys at different compositions. For all compositions considered, no intermixing is observed between the Cu-core and the Li-shell. Considering that the Li composition is smaller than 60%, the Li-Pb nanoalloys exhibit a B2 intermetallic compound structure with weak surface segregation. When the Li composition continues to increase, the nanoalloy shape progressively transforms into icosahedral configuration and exhibits an L12 structure. The calculated excess energy indicates that the 175-atom rhombohedron at the Li composition of 50% is more stable than the 147-atom icosahedron because a perfect B2 atomic arrangement is obtained in the former.

Modeling of self-organization processes in crystal-forming systems: Symmetry and topology code for the cluster self-assembly of crystal structures of intermetallic compounds

We performed the combinatorial and topological modeling of 1D, 2D, and 3D packs of symmetrically connected metal clusters in the form of tetrahedra А4. Three types of 1D chains with tetrahedral connectivity of 4, 6, and 8 were used to model 2D layers L-1, L-2, and L-3 and 3D frameworks FR-1, FR-2, FR-3, and FR-4. The model structures of the identified suprapolyhedral precursor clusters were used in topological analysis of crystal structures of intermetallic compounds (program package TOPOS and data bases ICSD and CRYSTMET). A match was found between the topological models of tetrahedral 3D frameworks and all types of crystal structures formed in binary systems; in Au–Cu: FR-1 for Cu3Au-cP4 (Auricupride), Cu2Au2-tP2 (Tetraauricupride), CuAu3-cP4 (Bogdanovite), and Cu2–x Au2 + x -cF4; in Mg–Cd: FR-3 for Mg3Cd-hP8, Mg2Cd2-oP4, MgCd3-hP8, and Mg2–x Cd2 + x -hP2; in Li–Hg: FR-2 for Li3Hg-cF16 and Li2Hg2-cP2 and FR-3 for LiHg3-hP8; in ternary system Li–Ag–Al: FR-2 for LiAg2Al-cF16 and Li2AgAl-cF16; and in quaternary system: framework FR-2 for LiMgPdSn-cF16. Framework FR-4 was identified in ternary intermetallic compounds A(Li2Sn2)-tI20, where A = Cu, Ag, Au. The structures of precursor nanoclusters were identified for other most abundant types of crystal structures of intermetallic compounds. For this purpose, we used the algorithms for partitioning the structural graph into nonintersecting cluster substructures and constructed the basal 3D network of the crystal structure in the form of a graph whose nodes correspond to the positions of the centers of precursor clusters. The cluster self-assembly was modeled for the following intermetallic compounds: Mg2Cu4-cF24, MgSnCu4-cF24, (ZrCu)Cu4-cF24,Mg2Zn4-hP12, (CaCu)Cu4-hP6, Cr3Si-cP8, Lu3Co(Fe3C)-cP16, Ca2Ge2(Cr2B2)-oC8, Y2Ni2(Fe2B2)-oP8, AlB2-hP3, Ca2Ge-oP12, CaHg2-hP3, Co2Ge(Ni2In)-hP6, Cs2Hg4-oI12, Ba4Po4-cF8, Mn5Ge3-hP16, and NaZn13-cF112. The symmetry and topological code of self-assembly from precursor nanoclusters was reconstituted for all crystal structure types of intermetallic compounds as: primary chain → microlayer → microframework. An abundance frequency analysis of topological and symmetry routes for the generation and evolution of precursor clusters enabled us to elucidate the crystal-formation laws in intermetallic systems on the microscopic level.

Modeling of the self-organization processes in crystal-forming systems. Tetrahedral metal clusters and the self-assembly of crystal structures of intermetallic compounds

A combinatorial and topological modeling of 1D, 2D, and 3D packings of symmetrically linked A4 tetrahedra has been performed. Three types of 1D chains with tetrahedra connectivities of 4, 6, and 8 were used to model 2D layers L-1, L-2, and L-3 and 3D frameworks FR-1, FR-2, FR-3, and FR-4. A family of tetrahedral structures with FR-1, FR-2, and FR-3 frameworks has been selected among the intermetallic compounds with chemical compositions of A 3 B, A 2 B 2, AB 3, A 2 BC, AB 2 C, and ABCD; this family includes more than 1900 compounds (TOPOS program package). It is found that the topological models of tetrahedral 3D frameworks are in correspondence with all types of the crystal structures formed in Au–Cu binary systems (FR-1 for Cu3Au (auricupride), Cu2Au2 (tetraauricupride), and CuAu3 (bogdanovite)), in the Mg–Cd system (FR-3 for Mg3Cd, Mg2Cd2, and MgCd3), in the Li–Hg system (FR-2 for Li3Hg and Li2Hg2 and FR-3 for LiHg3), in the Li–Ag–Al ternary system (FR-2 for LiAg2Al and Li2AgAl), and in the Li–Mg–Pd–Sn quaternary system (FR-2 for LiMgPdSn). Framework FR-4 has been established in ternary intermetallic compounds A(Li2Sn2); A = Cu, Ag, Au.

Intermetallic Compounds: Promising Inorganic Materials for Well-Structured and Electronically Modified Reaction Environments for Efficient Catalysis

An overview of the catalytic properties of intermetallic compounds has been made to provide a comprehensive understanding regarding (1) what intermetallic catalysts can do, (2) their fundamental roles in enhanced catalysis, and (3) their advantages over other inorganic materials. A number of chemical transformations using intermetallic catalysts have been surveyed and classified into three major divisions—hydrogenation/dehydrogenation, oxidation, and steam reforming and various subsections. The fundamental roles of intermetallic phases obtained from this survey were categorized into four types of effects: (a) electronic, (b) geometric, (c) steric, and (d) ordering effects. The unprecedented steric effects governed by the specific surface structures of intermetallic compounds highlight the unique capabilities of intermetallic materials. On the basis of this overview, we have concluded that intermetallic compounds have the following advantages for fine catalyst design: (i) control of the electronic structur...

Direct Metal Deposition by Laser in TiNi-Al System for Graded Structure Fabrication

Intermetallic phase formation was studied in powdered TiNi-Al system under layerwise laser cladding with the aim of forming a gradient of properties due to a change in the concentration relation of Al in the NiTi powder mixture from one layer to another. The relationship between the laser cladding parameters and the intermetallic phase structures in consecutively cladded layers were determined. The structure of intermetallic compounds formed by laser synthesis was studied by optical microscopy, measurement of microhardness, SEM with EDX analysis. Microhardness doubling from 500 HV to 1000 HV was achieved due to nitinol matrix enrichment by Al, which is promising for aerospace applications.

Influence of Gd, Nd and Ce Additions on Microstructures and Mechanical Properties of Ultra-light Dual Phase Mg-9Li-0.4Zr Alloys

Effects of various rare-earth elements (RE: Gd, Nd and Ce) additions on microstructures and mechanical properties of ultra-light dual phase Mg-9Li-0.4Zr alloy were investigated. The results indicated that Mg-9Li-5RE-0.4Zr alloys exhibited α-Mg, β-Li and RE-containing intermetallic compound structures. 5 wt.% Gd, Nd and Ce additions enhanced the strength properties of as-extruded Mg-9Li-0.4Zr alloy, but greatly deteriorated the ductility. The final mechanical properties of Mg-9Li-5RE-0.4Zr alloys were 161MPa∼167MPa in ultimate strength, 141MPa∼156MPa in yield strength and 20.8%∼32.5% in elongation. Heat treatment was hardly able to improve the mechanical properties for Mg-9Li-5RE-0.4Zr alloys.

The Study of Nb<sub>3</sub>Sn Phase Formation Process in Multifilamentary Superconductors for High-Magnetic-Field Systems

Recent investigations of the connection between the microstructure and the properties of Nb 3 Sn superconductors produced by the bronze method, for the large ITER magnets, have enabled us to develop wire fabrication technologies and to manufacture large quantities of such material that met all the technical requirements. The next stage is to study the possibility of increasing the critical current properties in a wide range of magnetic fields with the aim to apply them in the next generation of magnetic systems. In this study, the superconducting phase formation process, its structure, and the composition and critical properties of various layouts of Nb 3 Sn wire used under magnetic fields of 12-16 T have been investigated. It is shown that the intermetallic compound structure heavily depends on the grain structure of niobium filaments produced by multiple deformation of the composite wire with intermediate heat treatments. It is concluded that the improvement of the superconducting phase structure and the increase in current-carrying capability of wire in high magnetic fields are possible by the fine grain structure of initial niobium filament and an increase in the tin content of the bronze matrix.

Effect of Loading Stress on the Growth of Cn/Sn Intermetallic Compounds at High Temperatures

Fabrication of reliable solder joints is crucial in microelectronics. In this study we tested solder joints under different loads and temperature-controlled conditions to investigate the effect of external stress on the growth of interfacial Cu/Sn intermetallic compounds (IMCs). Test specimens were prepared by electroplating a layer of Sn (25 μm thick) on a copper substrate. Samples were then clamped in a micromechanical testing apparatus integrated within a furnace. Experiments were performed by using load feedback control to ensure a constant load of 25, 50, or 100 MPa at a constant temperature of 200°C for periods of 24, 72, or 120 h. We then compared samples that underwent stress with those that did not to elucidate the effect of stress and aging on the formation of IMCs. Our results indicate that the presence of external stress affects the formation of Cu/Sn IMCs, including the speed of formation and the resulting thickness. Moreover, the micrographic structure of IMCs formed under external stress varied substantially depending on the amount of stress applied.

The Application of Novel Platinum-Reinforced Tin-Silver-Copper Solder to Bifacial Photovoltaic Module for Improvement of Yield and Reliability

The characteristics of solder joints between the busbars of solar cells and copper ribbons can affect the performance of a photovoltaic (PV) module significantly. The resistivity of the joints and the intermetallic compound structures within the joints are the two main characteristics that impose a substantial impact on the yield and the reliability of the PV module. In this paper, we aim to present and analyze a novel platinum-reinforced tin-silver-copper (Sn-3.8Ag-0.7Cu-0.2Pt) as the lead-free solder material to connect copper ribbons to the metallization of bifacial solar cells. The performance of the PV module using platinum-reinforced solder is investigated by constructing two bifacial PV modules using the popular lead-free Sn-3.8Ag-0.7Cu solder and Sn-3.8Ag-0.7Cu-0.2Pt solder, respectively. Micrographs of the joints are obtained to show that the platinum-reinforced solder joint has fewer voids and a more evenly distributed and thinner intermetallic layer than that of a conventional SnAgCu solder joint. As a result, the physical attachment between the busbars and the ribbon using SnAgCuPt solder is stronger than that using SnAgCu solder. The power outputs of both PV modules are measured together with two commercial PV modules under the sun using an IV plotter. The results show that the total energy yield of the bifacial PV module with the new solder is about 6–10% higher than that with the conventional SnAgCu solder. The energy yield of the bifacial PV module using SnAgCuPt solder is 35.8% and 0.2% higher than that of the commercially available monofacial polycrystalline and monocrystalline PV modules, respectively.

Experimental evaluation of SnAgCu solder joint reliability in 100-μm pitch flip-chip assemblies

The intermetallic compound (IMC) evolution and the thermal–mechanical reliability of Sn–3.0Ag–0.5Cu (SAC305) solder joints were studied using air-to-air thermal shock testing of 100-μm-pitch peripheral-row flip chip assemblies. Flip chips assembled on organic substrates were subjected to air-to-air thermal shock testing between −55°C and 125°C, and the samples were removed at regular intervals for cross-sectioning and failure analysis. It was seen that on the die side, after 2000 cycles, all of the (Cu,Ni)3Sn4 had transferred to (Cu,Ni)6Sn5 due to strong cross-pad interaction between the chip-side Ni pad and substrate-side Cu pad, and thus, there was no premature solder cracking possibly due to the absence of dual IMC structure. On the substrate-side Cu interface, the Cu3Sn growth was hindered, and thus there was very little increase in Kirkendall voids in the Cu3Sn after 2000 cycles. Therefore, there was no premature brittle failure in the intermetallic. Failure analysis shows that the cracks in the outermost corner solder joint started to form after 2000 cycles near the chip-side pad, and the cracks propagated in the solder matrix around the IMC like a ring to create solder open. From the experimental data, crack propagation rate equation parameters and characteristic mean life were determined.

Intermetallic NaAu2 as a Heterogeneous Catalyst for Low-Temperature CO Oxidation

The enhanced stability and modified electronic structure of intermetallic compounds provide discovery of superior catalysts for chemical conversions with high activity, selectivity, and stability. We find that the intermetallic NaAu2 is an active catalyst for CO oxidation at low temperatures. From density functional theory calculations, a reaction mechanism is suggested to explain the observed low reaction barrier of CO oxidation by NaAu2, in which a CO molecule reacts directly with an adsorbed O2 to form an OOCO* intermediate. The presence of surface Na increases the binding energy of O2 and decreases the energy barrier of the transition states.

Structural relationships between single atom type crystal structures and intermetallic compound structures, as illustrated by Laves‐ and Hume‐Rothery phases

In comparison to the single atom type crystal structures, which are relatively simple and are concentrated in four types of structure (Cu, W, Mg, diamond), the crystal structures of intermetallic phases are manifold and often very complicated. At first sight there is no obvious connection between these types of crystal structures, however, a transition mechanism must exist for the solid‐state transition from the simple single atom type crystal structures to the intermetallic phase structures. Such a mechanism would show the inner connection between the structures. In this work the topic is dealt with from a crystallographic point of view. The transition between the structures can be described by the three steps (1) substitution of atoms, (2) systematically ejection of particular atoms from the emerging intermediate structure and (3) spatial relaxation especially of the atoms around the newly formed interstices. This general structural phase transition path will be discussed for two of the intermetallic classes, the Laves phases and the Hume‐Rothery phases. A suitable way of showing this is by making a comparison between the coordination polyhedra (atomic environments) of the single atom type crystal structures and those of the derived intermetallic crystal structures.

New icosahedral nanoclusters in crystal structures of intermetallic compounds: Topological types of 50-atom deltahedra D50 in samson phases β-Mg2Al3 and ɛ-Mg23Al30

A database of intermetallic compounds has been compiled using the TOPOS program package. This database includes 514 topological types, containing 12- and 13-atom icosahedral i clusters. An isolated group of 1649 i clusters is described by 14 point groups and their maximum symmetry D3d (\(\bar 3\)m) and Th(m\(\bar 3\)) is established, respectively, in 47 and 25 types of crystal structures. A structural analysis of the outer quasispherical shells showed that local 63-atom i configurations 1@12@50, which contain 50 atoms in the second layer, are implemented in 8 out of 19 cases. Examples of new topologically different types of 50-atom D50 deltahedra in the Samson phases ɛ-Mg23Al30 and β-Mg2Al3 are presented. Four topologically different sites with coordination numbers of 5, 6, 6, or 7 are established in the ɛ shell and seven sites with coordination numbers of 5, 5, 6, 6, 6, 6, or 7 are found in the β shell. The inner i clusters for the β-Mg2Al3 structure (with the symmetry \(\bar 3\)m) and the ɛ-Mg23Al30 structure (with the symmetry \(\bar 3\)) have a similar chemical composition, i.e., Mg7Al6 and Mg6Al7, and their 50-atom shells are chemically identical to 18Mg + 32Al. The configurations found supplement the series of known two-layer icosahedral Bergman and Mackay clusters in the form of deltahedra with 32- and 42-atom shells.

Monte Carlo simulations of the structure of Pt-based bimetallic nanoparticles

Pt-based bimetallic nanoparticles have attracted significant attention as a promising replacement for expensive Pt nanoparticles. In the systematic design of bimetallic nanoparticles, it is important to understand their preferred atomic structures. However, compared with unary systems, alloy nanoparticles present greater structural complexity with various compositional configurations, such as mixed-alloy, core–shell, and multishell structures. In this paper, we developed a unified empirical potential model for various Pt-based binary alloys, such as Pd–Pt, Cu–Pt, Au–Pt and Ag–Pt. Within this framework, we performed a series of Monte Carlo (MC) simulations that quantify the energetically favorable atomic arrangements of Pt-based alloy nanoparticles: an intermetallic compound structure for the Pd–Pt alloy, an onion-like multishell structure for the Cu–Pt alloy, and core–shell structures (Au@Pt and Ag@Pt) for the Au–Pt and Ag–Pt alloys. The equilibrium nanoparticle structures for the four alloy types were compared with each other, and the structural features can be interpreted in terms of the interplay of their material properties, such as the surface energy and heat of formation.

The μ3Model of Acids and Bases: Extending the Lewis Theory to Intermetallics

A central challenge in the design of new metallic materials is the elucidation of the chemical factors underlying the structures of intermetallic compounds. Analogies to molecular bonding phenomena, such as the Zintl concept, have proven very productive in approaching this goal. In this Article, we extend a foundational concept of molecular chemistry to intermetallics: the Lewis theory of acids and bases. The connection is developed through the method of moments, as applied to DFT-calibrated Hückel calculations. We begin by illustrating that the third and fourth moments (μ(3) and μ(4)) of the electronic density of states (DOS) distribution tune the properties of a pseudogap. μ(3) controls the balance of states above and below the DOS minimum, with μ(4) then determining the minimum's depth. In this way, μ(3) predicts an ideal occupancy for the DOS distribution. The μ(3)-ideal electron count is used to forge a link between the reactivity of transition metals toward intermetallic phase formation, and that of Lewis acids and bases toward adduct formation. This is accomplished through a moments-based definition of acidity which classifies systems that are electron-poor relative to the μ(3)-ideal as μ(3)-acidic, and those that are electron-rich as μ(3)-basic. The reaction of μ(3) acids and bases, whether in the formation of a Lewis acid/base adduct or an intermetallic phase, tends to neutralize the μ(3) acidity or basicity of the reactants. This μ(3)-neutralization is traced to the influence of electronegativity differences at heteroatomic contacts on the projected DOS curves of the atoms involved. The role of μ(3)-acid/base interactions in intermetallic phases is demonstrated through the examination of 23 binary phases forming between 3d metals, the stability range of the CsCl type, and structural trends within the Ti-Ni system.

Nanoclusters based on pentagondodecahedra with shells in the form of D32, D42, and D50 deltahedra in crystal structures of intermetallic compounds

The TOPOS software package has been used to form a database of intermetallic compounds containing pentagondodecahedral d clusters (528 crystal structures of intermetallic compounds, 111 topological types, and 47 space symmetry groups). On the whole, 606 atomic d configurations have been selected which are described by 14 point symmetry groups. Examples of nanoclusters are presented which are precursors of the crystal structures of intermetallic compounds with the outer shell in the form of deltahedra D, which are formed above dodecahedra. These nanoclusters are identified in the automatic mode of structural data processing: D32 (K8In6Ge40, Cs30Na3Sn162), D 42 (Ru3Be17, Y3Cd18, Ca3(Cd17Al)), and D 50 (Yb3Zn18, Ce3(Au14Sn3), Pr3Cd18, Eu4Cd25), where 32, 42, and 50 are the numbers of atoms in the shell. Similar deltahedra were found previously in icosahedral nanoclusters (precursors of intermetallic compounds). Structures with the dodecahedral nanocluster precursors containing D42 and D50 deltahedra are approximants of MCd5.7 (M = Yb or Ca) quasicrystals and belong to the family of MCd6 (M = Ce, Pr, Nd, Sm, Eu, Gd, Dy, Yb, Y, or Ca).

Evolution of Intermetallic Compounds between Sn-0.3Ag-0.7Cu Low-silver Lead-free Solder and Cu Substrate during Thermal Aging

The growth, transformation, and lattice structure of intermetallic compounds formed between Sn{0.3Ag{0.7Cu lead-free solder and copper substrate were investigated. Dip soldering was used to initiate the reaction between the solder and substrate. An ·-Cu6Sn5 intermetallic phase possessing a hexagonal lattice structure was found at the as-soldered interface. Thermal aging at a number of conditions resulted in the formation of a Cu3Sn intermetallic phase between the Cu6Sn5 layer and the copper substrate. -Cu3Sn with an orthorhombic lattice structure was found together with hexagonal Cu3Sn. Subsequently, the activation energies of the intermetallic phases were calculated and compared to results obtained from the literature. The comparison showed that good agreement existed between the flndings from this study and literature data within a similar temperature range.