Properties of Lead-Free Solders, Table of Contents

Properties of Lead-Free Solders

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Note: Alloy compositions are given in the form "Sn-2.5Ag-0.8Cu-0.5Sb," which means: 2.5 % Ag, 0.8 % Cu, and 0.5 % Sb (percent by mass), with the leading element (in this case, Sn) making up the balance to 100 %.

Abbreviations for metallic elements appearing in this database:

Ag: silver
Al: aluminum
Au: gold
Bi: bismuth
Cd: cadmium
Cr: chromium Cu: copper
In: indium
Mo: molybdenum
Ni: nickel
Pb: lead
Pd: palladium Pt: platinum
Sb: antimony
Sn: tin
W: tungsten
Zn: zinc

Sn-Ag-Cu: Refers to compositions near the eutectic

Table of Contents:

1. Mechanical Properties: Elastic modulus, elongation, tensile strength, yield strength

Table 1.1. Strength and Ductility of Low-Lead Alloys Compared with Alloy Sn-37Pb (NCMS Alloy

A1), Ranked by Yield Strength (15 Alloys) and by Total Elongation (19 Alloys)

Table 1.2. Tensile Properties of Lead-Free Solders

Table 1.3. Elastic Properties of Sn-37Pb (eutectic) and Sn-3.5Ag

Table 1.4. Elastic Properties of Sb-2.5Ag-0.8Cu-0.5Sb (Castin™) and Sn-37Pb Eutectic - A

Table 1.5. Elastic Properties of Sb-2.5Ag-0.8Cu-0.5Sb (Castin™) and Sn-37Pb Eutectic - B

Table 1.6. Parameters for: Norton Equation, de/dt = A·sⁿ·exp(-Q/(RT)); Dorn Equation,

de/dt = A·(sⁿ/T)·exp(-Q/(RT)); Stress-relaxation Rate, ds/dt = A·(s-s_t)ⁿ ·exp(-Q/(RT));

and Strain-Rate Sensitivity, s = C·(de/dt)^m; for Two Lead-Free Alloys

Table 1.7. Steady-State Creep Properties and Associated Mechanisms for Three Lead-Free Solders

and Sn-37Pb Eutectic

Table 1.8. Stress Exponents and Activation Energies for Dorn Equation for Tin and Four Lead-Free

Solder Alloys

Table 1.9. Activation Energy versus Strain Rate for Two Lead-Free Eutectic Solders (Sn-3.5Ag and

Sn-9Zn)

Table 1.10. Elastic Properties of Metallic Elements Used in Electronic Packaging

Table 1.11. Material Properties of a Via-in-Pad Chip-Scale Package Printed Circuit Board Assembly

Table 1.12. Elastic Properties and Thermal Expansion Coefficient of Electronic-Packaging Materials and

Lead Solder Alloys

Table 1.13. Lead-Free Solder Alloys: Tensile and Shear Strengths

Table 1.14. Lead-Containing Solder Alloys: Tensile and Shear Strengths

Table 1.15. Shear Strengths of Three Lead-Free Solders and Tin-Lead Eutectic (by Ring-and-Plug Test)

Table 1.16. Mechanical Properties of Tin, Tin-Lead, and Four Lead-Free Solder Alloys (by Ring-and-

Plug Tests)

Table 1.17. Shear Strengths, Solidus and Liquidus Temperatures, and Wetting Angles of Experimental

Sn-Ag-Cu Solder Alloys

Table 1.18. Physical and Mechanical Properties of Lead-Free Alloys and Sn-37Pb (eutectic)

Table 1.19. Pure Copper, Tin and Nickel, and Their Intermetallics: Room-Temperature Physical and

Table 1.20. Effects of Transition Metals on Vickers Hardness and Ultimate Tensile Strength of

Sn-4.7Ag-1.7Cu Solder Alloys

Table 1.21.1. SnAgCu Dynamic Elastic Constant

Table 1.21.2. SnAgCu Dynamic Elastic Constant (cont.)

Table 1.22.1. SnAgCu Elastic Properties vs. Temperature

Table 1.22.2. SnAgCu Elastic Properties vs. Temperature (cont.)

Table 1.22.3. SnAgCu Elastic Properties vs. Temperature (cont.)

Table 1.22.4. SnAgCu Elastic Properties vs. Temperature (cont.)

Table 1.22.5. SnAgCu Elastic Properties vs. Temperature (cont.)

Table 1.22.6. SnAgCu Elastic Properties vs. Temperature (cont.)

Table 1.23. SnAgCu - Coefficient of Thermal Expansion Data. Sample As-cast #1

Table 1.24. SnAgCu - Coefficient of Thermal Expansion Data. Sample As-cast #2

Table 1.25. SnAgCu - Coefficient of Thermal Expansion Data. Sample Aged #1

Table 1.26. SnAgCu - Coefficient of Thermal Expansion Data. Sample Aged #2
Table 1.27. Mechanical Properties of Three Selected Pb-free Alloys: Sn-3.2Ag-0.8Cu, Sn-3.5Ag,
and Sn-0.7Cu

Figure 1.1. Creep data at 75^oC for Sn-Ag-Cu, Sn-Ag-Bi, Sn-Ag, Sn-Bi, and Sn-Pb solder alloys

2. Thermal Properties

2.1. Solidus, Liquidus, and Melting-point Temperatures

Table 2.1.1. Liquidus and Reflow Temperatures of Candidate Lead-Free Solder Alloys for

Replacing Eutectic Tin-Lead Solder

Table 2.1.2. Melting Temperatures of Lead-Free Solders

2.2. Thermal Properties: Miscellaneous

Table 2.2.1. Thickness (µm) of Intermetallics in Solder Alloys Aged at 150 ºC

Table 2.2.2. Thermal and Electrical Properties of Castin™ (Sb-2.5Ag-0.8Cu-0.5Sb)

Table 2.2.3. Physical and Mechanical Properties of Sn-2.8Ag-20.0In and Sn-37Pb Eutectic Solders

Table 2.2.4. Some Physical Properties of Materials Used as Electronic Packaging Conductors

Table 2.2.5. Thermophysical Properties of Metallic Elements Used In Electronic Packaging

Table 2.2.6. Some Properties of Materials Commonly Used In Electronics - A

Table 2.2.7. Some Properties of Materials Commonly Used In Electronics - B

Table 2.2.8. Electrical Resistivity and Temperature Coefficient (TCR) of Pure Metallic Elements

Used in Electronic Packaging

Table 2.2.9. Wetting Properties of Sn-2.8Ag-20.0In and Sn-37Pb Eutectic Solders

Table 2.2.10. Wetting Times and Forces (at 300 ºC): Lead-Free Solder Alloys, and Eutectic Tin-Lead

Table 2.2.11. Wetting Times (at 250 ºC) of Lead-free Solder Alloys

Table 2.2.12. Onset of Melting Temperatures for Five Sn-Ag-Cu Lead-Free Solder Alloys

Table 2.2.13. Solidus Temperatures and Wetting Contact Angles of Selected Lead-Free Solder Alloys

with Use of RMA (GF-1235) Flux

Table 2.2.14. Solidus and Liquidus Temperatures and Wetting Angles of Some Lead-Free Alloys on

Copper

Table 2.2.15. Melting Properties, Resistivity, Wettability and Hardness of Lead-Free Solders

Table 2.2.16. Wetting Contact Angles of Sn-Ag, Sn-Bi, and Sn-Zn Alloys on Copper: Eutectic, and

With 1% Addition of Ternary Elements

Table 2.2.17. Wetting Contact Angles on Copper of Sn-Bi Alloys: Eutectic, and With 1% Addition of

Ternary Elements

Table 2.2.18. Wetting Properties of Pure Tin, Four Lead-Free Tin Alloys and Three Lead-Tin Alloys

Table 2.2.19. Lead-Free Solder Alloys: Solidus and Liquidus Temperatures, Coefficient of Thermal

Expansion, Surface Tension, and Electrical Resistivity

Table 2.2.20. Fluid Properties of Some Molten Lead-Free Solders

Table 2.2.21. Densities and Costs of Popular Solder Metals and Alloys - A

Table 2.2.22. Densities and Costs of Popular Solder Metals and Alloys - B

Table 2.2.23. Cost of Lead-Free Solder Alloys Relative to That of Sn-37Pb Eutectic

A. Solder Alloys for Plated-Through Holes

3. Candidate Alloys for Replacing Lead-Alloy Solders

Table 3.1. Criteria for Down-Selection of Lead-Free Alloys

Table 3.2. Chemical Compositions of 79 Lead-Free Solder Alloys Down-Selected for Preliminary

Testing by the National Center for Manufacturing Sciences (NCMS).

4. Miscellaneous

A. Major Considerations for Replacement Lead-Free Solders

Table 4.1.a. Designation and Composition of Lead-Free Solders (It includes alloys from A1 to EN9)

Table 4.1.b. Designation and Composition of Lead-Free Solders (It includes alloys from F1 to F65 and

the reference alloy A0)

5. Useful References

5.1. References to Tabular Data

5.2. Reference Books

5.3. Useful URLs

Key words: alloys, aluminum, antimony, atomic weight, bibliography, bismuth, Castin, chemical, chromium, coefficient, composition, conductivity, copper, costs, creep, ductility, elastic, electrical, electronic, elements, elongation, eutectic, expansion, gold, hardness, indium, intermetallic, lead, lead-free, liquidus, material, mechanical, melting, metallic, modulus, molybdenum, nickel, packaging, palladium, physical, platinum, Poisson ratio, PCB, printed circuit board, properties, replacement, resistivity, silver, solders, solidus, strength, surface tension, temperature, tensile, thermal, thermophysical, tin, tungsten, viscosity, wetting, Young’s modulus, zinc.

Useful Conversion Factors:

Standard Acceleration of Gravity, g:

g = 32.174 f/s² = 9.80665 m/s² (not to be confused with "gram", g)

Electrical Conductivity:

1 S (siemens) = 1 O^–1 (reciprocal ohm)

Density:

1 g/cm³ = 0.036127 lb_m/in³ = 62.428 lb_m/ft³

Energy:

1 cal = 4.187 J (joule)

1 Btu = 1055.056 J = 252 cal = 0.252 kcal (kilocalories)

Force:

1 lb_f= 4.4482 N (newton)

1 kg_f = 9.80665 N

1 dyne = 10^–5 N

Length:

1 in = 2.54 cm = 0.0254 m (exact)

1 ft = 30.48 cm = 0.3048 m (exact)

Mass:

1 lb_m = 0.45359 kg; 1kg = 2.20463 lb_m

Pressure (or Tensile stress):

1 Pa (pascal) = 1 N/m²

1 psi = 6894.76 Pa = 6.89476 kPa

1 kps = 6.89476 MPa

Specific Heat (Capacity):

1 cal/(g·K) = 1 Btu/(lb_m·F) = 4.187 J/(kg ·K)

Temperature; temperature intervals:

Fahrenheit temperature F = 1.8·C + 32, where C is Celsius temperature

Kelvin temperature K = C + 273.15

1 K (1 kelvin) = 1 ºC (1 Celsius degree) = 1.8 ºF (1 Fahrenheit degree = temperature interval)

Thermal Conductivity:

1 W/(m·K) = 0.5778 Btu/(ft·hr ·°F)

Explanatory Note:

This version (11 February 2002) represents our present collection of information on properties of lead-free solders. We are just now beginning to have enough properties data to begin consolidating duplicate data, to better organize the tables into a more useful order, and to begin some evaluation of uncertainties. Also, no systematic mining of resources from journals that publish articles on relevant properties of lead-free solders has yet been done by us, but is a planned next step. However these next steps await further funding. We hope to greatly extend the work beyond this present state into a larger and more useful one. Your patience is appreciated. – the authors.

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This page was last updated on: 2002 February 11 8:30:50 pm