Laminate materials for nolead solder applications eric holman and terry smith isola introduction environmental concerns about lead entering ground water systems has led to legislation to ban the use of lead in many applications including water pipes and paint. The materials in the alloy of composition sn9zn of purities of 99. Leadpull data shows higher average pull forces for all of the pbfree alloys versus the snpbag paste used as a control, with the exception of snbi. Double peritectic behavior of agzn intermetallics in sn. Electric arc working, brazing and soldering may create one or more of the following health or physical hazards. Hence a wide range of solder alloys exist, and only major ones are listed below. Behavior of intermetallics in liquid snznag solder alloys. Eutectic sn58bi solder was a significant solder alloy with good wettability, good. Behavior of intermetallics in liquid snznag solder alloys volume 18 issue 9 jenn ming song, kwang lung lin. As part of this effort, we have developed a new leadfree solder that consists of tin sn, zinc zn, and aluminum al and yet offers superior productivity and joint.
These alloys include all nonpatented alloys, as well as the castin and sn100c alloys. Solder alloys are metallic materials that are used to connect metal workpieces. A pbfree solder alloy and a soldered bond using the same, in which the solder alloy has no harmful environmental effect but has a solderability comparable to that of the conventional pbsn solder alloy. Interfacial microstructure and shear strength of ag nano. Effect of indium content on the melting point, dross, and. Nevertheless, the main alternative options such as sncu, snzn, snag have. However, new solder alloys must fulfill a number of other requirements.
Mechanical properties of tin, tinlead, and four leadfree solder alloys by ringandplug tests table 1. Mechanical properties of snzn leadfree solder alloys. Interfacial properties of znsn alloys as high temperature. In order to research several properties of sncu solder alloys, a lot of. The properties and performance of leadfree solder alloys such as fluidity and. Selection of the solder alloys, for the electronic industry applications, is conditioned by their mechanical properties due to the stress produced in service. Effect of the bi content on the mechanical properties of a snznalbi solder alloy d.
Thermal expansion and electrical resistivity of alloys based on snzn eutectic. Low melting points, suitable mechanical properties, and relatively low costs characterize the snzn alloys58, when compared with others leadfree solder alloys. This is achieved by melting the alloy and then cooling it down. Structure and properties of sncu leadfree solders in electronics.
Physical and mechanical properties of leadfree alloys and sn37pb eutectic table 1. Mechanical properties of solderjointed copper rods with. Numerous studies have been conducted on alloys based on snbi, snzn, and snag. The choice of specific alloy depends on its melting point, chemical reactivity, mechanical properties, toxicity, and other properties. Mechanical properties and microstructure investigation of. Provided is a glass for an automotive vehicle capable of preventing cracking in glass substrate for an automotive vehicle over time when one surface of a metal terminal is soldered to a silver electrode formed on the glass substrate using a solder alloy and flux. National institute of technology rourkela, orissa 769008, india this is to certify that the thesis entitled, determination and characterization of lead free solder alloys submitted by prerna mishra in partial fulfillment of the requirement for the award of master of technology degree in metallurgical and materials engineering with specialization in metallurgical and materials. Wo2015129840a1 soldering method and glass for automotive. Zn solder alloys are also not hazardous to human health. Additionally, this alloy s lower cost per mass unit compared to that of sac. Snzn eutectic alloy has been considered as one of the leadfree solder materials that can replace the toxic sn37pb solder without increasing soldering temperature. However, when al atoms are added in place of the zn, the al atoms oxidize, and a dense al 2 o 3 oxide film is instantly formed.
Thermal and mechanical properties of snznbi leadfree solder alloys. Determining solder alloy and base metal compatibility. The metal terminal is copper or brass, and the soldering is performed by keeping the ratio of. Pdf development and characterization of snznbi lead free. Thermal expansion, electrical resistivity, and spreading area of sn. Lead free solder alloys snzn and snsb prepared by mechanical. However snzn solder alloy has some limitations like. The problem is overcome by soldering copper with an alloy of 97.
If the amount of znphase in the snzn eutectic alloy can be reduced or. The solder alloy of the present invention either consists of zn. Investigations on microhardness of snzn based leadfree. Snzn eutectic alloy is a replacement for pbbearing solder alloys 1, demonstrating better mechanical properties, tensile stress and strain than sn40pb and sn3. The snzn eutectic alloy is the nontoxic pbfree solder alloy alternative having a melting temperature which is closest to that of the eutectic snpb alloy 198 c and 183 c, respectively. Low temperature soldering is one of the key technologies before the accomplishment of total leadfree conversion in electronics industries. Structure and properties of sn9zn leadfree solder alloy.
Among them, the snznal system has been studied and reveals promising properties. Wetting properties of snzn and znal alloys on cu and al substrates were studied. Double peritectic behavior of agzn intermetallics in snznag solder alloys volume 19 issue 9 jennming song, kwanglung lin. C thermodynamic data for the snznbi system 54 d binary agcu phase diagram 55. Pdf development of snznal leadfree solder alloys semantic.
However, there is still potential for the further development of sncu solder alloys with higher properties. Kitajima et al development of snznal leadfree solder alloys solder in air significantly deteriorates. Damage by heat exposure and corrosion in humidity are two of the main concerns. Evaluation of nickelpalladiumfinished ics with lead. It is known that al atoms are liable to release electrons partially due to their. While snzn eutectic alloy has excellent properties as low temperature solder, it has some drawbacks. Improve soldering packaging by lowering melting temperature 30. In the expectation of a possible connection between sncu 6sn 5 and snzn binary eutectics, several alloy compositions were selected along a possible joining path. Wetting of cu and al by snzn and znal eutectic alloys. Characteristics of s nzn cast alloys with the addition of. Snzn solder has low cost and good mechanical properties that are suitable for soldering.
The potentials of the newly designed znxsn x40, 30, and 20 mass% alloys as high temperature leadfree solders and their interface properties on cu substrate were investigated, focusing on the interface microstructure and mechanical properties. Soldering alloys based on the sncu and snzn alloy systems have been found to be amongst the most favorable lead free alternatives. The results of this research study provide necessary data for the modeling of solder joint reliability for a range of snagcu compositions and a baseline. The easy oxidation of snzn alloys was a fatal weakness. Because of environmental and health concerns, some alternative solder alloys, named leadfree ones, are being developed.
The database contains all the important solder alloy systems, e. The effect on the mechanical properties of adding the quaternary element bismuth to the sn3. Despite good mechanical properties, wetting properties of snzn alloys are inferior when compared to those of sn37pb alloy. However, new solder alloys must fulfill a number of other requirements in both economic and physicalchemical points of view. Solder alloy melting temperature metal weight percent melting temperature solidus liquidus tin lead silver other degrees c degrees f 0 100 327 621 2 98 316322 601611 5 95 3014 574597 10 90 268302 514576 15 85 225290 437554 20 80 183280 361536. Request pdf lead free solder alloys snzn and snsb prepared by mechanical alloying the mechanical alloying ma processes of tin9zinc sn9zn and. A potential solution is to adjust the soldering parame. Effect of the bi content on the mechanical properties of a.
Thermocalc software is pleased to announce the release of tcsld3, a thermodynamic database for. This study investigates the effect of bi content on the microstructure, thermal, and mechanical properties of the eutectic snzn alloy. Snznal solder for aluminum soldering to produce 1 product, the required amount of conventional material is 2. Ogunjo department of physics, school of sciences, federal university of technology, akure, nigeria thermodynamic properties of al were calculated using the molecular interaction volume model mivm by analyzing the. Influence of nanoparticle addition on the formation and. In view of the need for a leadfree, dropin replacement for the widely used 40pb60sn neareutectic solder m. Effects of zn addition on mechanical properties of eutectic sn58bi solder during. Tcsld3 tcs solder alloy solutions database, version 3. Copper alloy joints will crack through the interface due to hard and brittle film of cu 31 sn 8 or cu 6 sn 5 on exposure to elevated temperature below the melting point of solder. Structure and properties of sncu leadfree solders in. Over the past ten years, attention has been focused on smaller applications, which. Available formats pdf please select a format to send. Low melting point solders such as snzn and snbi alloys are expected to be used as a substitute for the snpb eutectic solder, because the melting temperatures.
Many of these alloys are compatible with the flux chemistries currently used with tinlead alloys, while some alloys require special flux. Moreover, snzn alloy is advantageous from the economic point of view because zn is a low cost metal. Microstructural and mechanical properties analysis of extruded sn. Oh 2 pdf number and zno pdf number 211486, respectively. Compared with traditional snpb solder, sncu solders exhibit the higher melting point 1418. It is well known that the poor oxidation resistance of the snzn eutectic alloy is due to the oxidation of zn, which exists in both primary and eutectic phases. Spreading tests were carried out for 3 min, in air and under protective atmosphere of nitrogen, with the use of fluxes. Pdf thermal and mechanical properties of snznbi lead.
Pdf creep deformation behavior of snzn solder alloys. Shear strengths, solidus and liquidus temperatures, and wetting angles of experimental snagcu solder alloys. A lowtemperature solder is required for minimizing heat damage and warpage during the process and for increasing the package density, e. Leadfree solder, cusnzn system, quasiperitectic reaction, microstructure introduction with the banning of pb as a component in solder alloys, much effort has been directed at finding an acceptable replacement for the traditional eutectic pbsn solder alloy previously used in the assembly of electronic components. Thermal and mechanical properties of snznbi leadfree.
Snzn alloys have good mechanical properties and can be used to soldering of copper and aluminum, provided proper. In only one case snzn bi alloy, a slight negative wetting angle was noted at the heel. Effect of aluminum addition on the microstructure and properties of. Effects of zn addition on mechanical properties of eutectic sn58bi.
The yield and ultimate tensile strength obtained for the snznal alloy are a. Thermodynamic properties of al in ternary leadfree solder. Low price per mass unit of snzn solder is also a favorable factor. Correlations of microstructure and mechanical properties.
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