Silver alloys (brazing, silver-gold and contact alloys) Ag alloys

Silver-rich alloys: Ag-28 wt% Cu eutectic (BAg-8), silver-gold alloys AgAu 0.2 to AgAu 10, Ag-1 wt% Sb (Ag99/Sb1), Ag-Cu-Zr active-braze compositions and Ag-Pd contact grades

A family profile for silver-rich alloys.

9 sources · Updated 2026-10-26 · CC BY 4.0

Evidence level

2 of 5

Lab-measured

Braze at low temperature

780 °C

Carry a little load

272 MPa

Conduct heat and electricity

371 W/m K

Recipe, share of the weight

  • Ag not statedSilver
  • Cu not statedCopper
  • Sb not statedAntimony

Best for

Silver brazing of copper, nickel and steel at about 780 degC (BAg-8 eutectic, 72 Ag and 28 Cu)

Weakest at

Tarnish in sulphur-bearing air and atomic-oxygen exposure in orbit; no sourced rate for any of these alloys was read in this run

Risk at a glance

  • People Low. Exposure limit set for silver dust
  • If it fails No data. No failure risks recorded
  • Corrosion No data. No corrosion data recorded

Quick facts: Ag alloys

Key properties of Ag alloys
PropertyValueBasis
Density10 to 10.9 g/cm³2 sourced values across conditions
Yield strength272 MPa1 sourced value
Tensile strength200 to 440 MPa3 sourced values across conditions
Young's modulus80 to 85 GPa1 sourced value
Thermal conductivity371 W/(m·K)1 sourced value
Thermal expansion (CTE)19.6 ppm/K1 sourced value
Melting point780 to 975 °C2 sourced values across conditions
Electrical resistivity20.4 x10-9 ohm m1 sourced value

What is the density of Silver alloys (Ag alloys)?

Silver alloys (Ag alloys) has a density of 10 to 10.9 g/cm³. The range covers 2 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.

What is the thermal conductivity of Silver alloys (Ag alloys)?

Silver alloys (Ag alloys) has a thermal conductivity of 371 W/(m·K). The source and test conditions are listed in the properties table on this page.

What is the coefficient of thermal expansion of Silver alloys (Ag alloys)?

Silver alloys (Ag alloys) has a coefficient of thermal expansion of 19.6 ppm/K. The source and test conditions are listed in the properties table on this page.

What is the melting point of Silver alloys (Ag alloys)?

Silver alloys (Ag alloys) has a melting point of 780 to 975 °C. The range covers 2 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.

What is the yield strength of Silver alloys (Ag alloys)?

Silver alloys (Ag alloys) has a yield strength of 272 MPa. The source and test conditions are listed in the properties table on this page.

What is Silver alloys (Ag alloys) used for?

Uses recorded in the sources include Brazed joints in aero-engines and aerospace fuel-line assemblies (BAg-8 Cusil); Silver-copper-lithium braze in the Skylab M-552 brazing experiment (related braze, not BAg-8); Brazing of electrical components to copper and nickel (BAg-8 S72).

Why it exists

Silver-rich alloys are used where a low melting point, good conduction and a known joining record matter. BAg-8 melts at 780 degC and is used for brazing copper, nickel and steel in aero-engines and fuel lines. Silver-gold alloys melt at 960 to 975 degC and have a density of 10.5 to 10.9 g/cm3. Space data for these alloys are thin: the Skylab braze used a related silver-copper-lithium alloy, and no flight result for BAg-8 was read.

Where it's used

Aerospace brazing

Morgan's Cusil BAg-8 data sheet lists aero-engine repair, aerospace fuel-line assemblies, vacuum tubes and waveguide assemblies as typical uses.

Brazing in space

NASA's Skylab M-552 experiment in 1974 brazed a nickel ferrule to a nickel tube with Lithobraze BT (71.8 percent Ag, 28 percent Cu, 0.2 percent Li) in near-zero gravity. The alloy is related to BAg-8, not the same grade.

Recipe

Silver-rich alloys: Ag-28 wt% Cu eutectic (BAg-8), silver-gold alloys AgAu 0.2 to AgAu 10, Ag-1 wt% Sb (Ag99/Sb1), Ag-Cu-Zr active-braze compositions and Ag-Pd contact grades

BAg-8 is a silver-copper eutectic with 72 percent silver and 28 percent copper by weight; its solidus and liquidus are both 780 degC as printed by the Cusil data sheet. Silver-gold alloys AgAu 0.2 to AgAu 10 are listed in one German table. Silver-antimony (Ag99/Sb1, 1 percent antimony) is listed by Goodfellow. Silver-zirconium-copper and silver-palladium compositions are not covered by a data sheet read in this run.

What Ag alloys is made of
IngredientShare of the weightWhat it does
Silver Ag not stated The base metal of the brazing alloy. It gives the low melting point of the eutectic and a conductive, reflective surface in the other grades.
Copper Cu not stated Forms the eutectic with silver at 780 degC. It is the hardening addition and the reason the alloy is stronger than fine silver; the Aimtek sheet calls it a Cu 28 percent alloy.
Antimony Sb not stated Listed by Goodfellow as the alloying addition in its Ag99/Sb1 wire. The page does not print a number for the change it causes.

Weight shares are as printed in the sources.

What it can do

Braze at low temperature

780 °C

measured

BAg-8 melts at 780 degC, both solidus and liquidus, so it can be used as a eutectic filler.

Carry a little load

272 MPa

measured

The Cusil data sheet prints a 0.2 percent yield strength of 272 MPa and a tensile strength of 372 MPa for test pieces.

Conduct heat and electricity

371 W/m K

worked out from the formula

The supplier calculates a thermal conductivity of 371 W/m K for BAg-8 and prints a resistivity of 20.4 x10-9 ohm m.

How it compares

No source in this record compares the silver alloys with each other or with other fillers under the same test, so no ranking is made. BAg-8 is a eutectic and is brazed at one temperature; the silver-gold alloys melt over a 15 degC range from 960 to 975 degC. The values come from one supplier each, so they should be checked against the supplier certificate for the form and temper.

The same measurements for each material, so you can compare them. Each row names the key condition under the value; the full conditions and methods are in the numbered notes under Technical details. Other materials are shown beside it; each was measured under its own conditions, so open its page before comparing closely. Compare every grade in the family.

Benchmarks
MeasurementAg alloysAuAgPtPdRhRuOsAu alloysAuSnAg 92.5 Cu 7.5Pd-AgPd-Cu, Pd-Ni, Pd-CrPt-RhPt-IrPt-W, Pt-Cu
Thermal behavior and safety
Solidus and liquidus of BAg-8 (72 Ag, 28 Cu)780 °C11065 °C961.9 °C1769 °C1555 °C1964 °C2334 °C3033 °C955 °C280 °C788 to 891 °Cno data1397 °C1840 to 1870 °C1790 to 1800 °C1865 to 1885 °C
Thermal conductivity of BAg-8 (calculated)371 W/m K3320 W/(m K)429 W/(m K)74 W/(m·K)72 W/(m.K)150 W/(m·K)117 W/(m·K)87.6 W/(m·K)49 W/(m K)57 W/mKno data61 W/(m.K)no datano datano datano data
Melting range of silver-gold alloys AgAu 0.2 to AgAu 10960 to 975 °C71065 °C961.9 °C1769 °C1555 °C1964 °C2334 °C3033 °C955 °C280 °C788 to 891 °Cno data1397 °C1840 to 1870 °C1790 to 1800 °C1865 to 1885 °C
Physical and electrical
Density of BAg-8 (Cusil)10 Mg/m3219.3 g/cm³10.5 g/cm³21.45 g/cm³12.02 g/cm³12.42 g/cm³12.36 g/cm³22.5 g/cm³15.8 g/cm³14.7 -10.4 g/cm³10.9 g/cm³10.8 g/cm³19.97 g/cm³21.54 g/cm³21.26 g/cm³
Electrical resistivity of BAg-820.4 x10-9 ohm m62.2×10^-8 ohm m1.63 µΩ·cm10.6 µΩ·cm10.8 uOhm.cm43.3 nΩ·m71 nΩ·m8.8 µΩ·cm15.5 µΩ·cmno data1.8 µOhmcm15 uOhm.cmno datano datano data62 to 68 µOhm cm
Density of silver-gold alloys AgAu 0.2 to AgAu 10Row values of the German silver-gold table10.5 to 10.9 g/cm³19.3 g/cm³10.5 g/cm³21.45 g/cm³12.02 g/cm³12.42 g/cm³12.36 g/cm³22.5 g/cm³15.8 g/cm³14.7 -10.4 g/cm³10.9 g/cm³10.8 g/cm³19.97 g/cm³21.54 g/cm³21.26 g/cm³
Other measurements
Coefficient of thermal expansion of BAg-819.6 x10-6 per °C414.2 ppm/K19.1 ppm/K8.93 ppm/K11.8 ppm/K8.46 ppm/K6.78 ppm/K4.57 ppm/K14 ppm/K16 ppm/°C19 x10-6 K-1no datano datano datano datano data
0.2 percent offset yield strength of BAg-8272 MPa5no datano data70 MPano datano datano datano datano datano datano data150 MPano data180 to 670 MPa220 MPa400 to 1000 MPa
Tensile strength of BAg-8Printed in the Physical Properties table372 MPano datano data150 MPano datano datano datano data616 MPa275 MPa207 MPa310 MPano data300 to 680 MPa340 MPa800 to 1100 MPa
Elongation of BAg-8Printed in the Physical Properties table19 %no datano data40 %no datano datano datano data13 %no datano data36 %3 %1.5 to 32 %32 %2 to 20 %
Modulus of elasticity of soft silver-gold alloys80 to 85 GPa8no datano data170 GPa121 GPa380 GPa447 GPa559 GPano data68 GPano data114 GPano data208 GPa202.3 GPa230 GPa
Tensile strength of soft silver-gold alloys200 to 220 MPa9no datano data150 MPano datano datano datano data616 MPa275 MPa207 MPa310 MPano data300 to 680 MPa340 MPa800 to 1100 MPa
Tensile strength of hard silver-gold alloys380 to 440 MPa10no datano data150 MPano datano datano datano data616 MPa275 MPa207 MPa310 MPano data300 to 680 MPa340 MPa800 to 1100 MPa

Why choose it, and why not

Good for

  • Eutectic brazing filler for copper, nickel and steel at 780 degC. The Cusil sheet lists copper, nickel, Kovar and carbon steel as suggested base materials.
  • Silver-gold alloys where a melting range near 960 to 975 degC and a density of about 10.5 to 10.9 g/cm3 are needed.

Watch out for

  • Tarnish. No sourced sulphur or tarnish rate was read for any silver alloy in this family.
  • Space data. No atomic-oxygen, outgassing or thermal-vacuum record for BAg-8 or the silver-gold alloys was read. The LDEF silver mirror result is for silver under FEP, not an alloy.
  • Grade mixing. BVAg-8 is a vacuum grade with a different specification, and the Skylab braze is a silver-copper-lithium alloy. Do not use their values for BAg-8.

BAg-8 is the best-supported grade in this file: a eutectic brazing filler with a 780 degC melting point, a published density, strength and resistivity. The other silver alloys are only partly covered; the silver-gold table gives properties, while silver-antimony, silver-zirconium-copper and silver-palladium need their own datasheets before any use.

Technical details

For scientists and researchers. Everything above comes from the record below: every number with its method, its conditions and its source.

Notes

The method, full conditions and any caveat for the numbered rows above.

Notes for the numbered rows
#MeasurementMethodConditionsCaveat
1Solidus and liquidus of BAg-8 (72 Ag, 28 Cu)Printed as both liquidus and solidus in the Physical Properties table; the data sheet calls its values indicative onlyalloy BAg-8, 72 wt% Ag and 28 wt% Cubasis eutectic, solidus equal to liquidus as printedAimtek S72 data sheet prints 779 degC for solidus and liquidus of the same nominal composition (1435 degF); the two sources differ by 1 degC.
2Density of BAg-8 (Cusil)Printed in the Physical Properties table of the data sheet as 10.0 Mg/m3 (0.361 lb/in3)alloy BAg-8, 72 wt% Ag and 28 wt% Cutemperature not stated—
3Thermal conductivity of BAg-8 (calculated)Printed as calculated by the supplier, not measuredalloy BAg-8, 72 wt% Ag and 28 wt% Cutemperature not stated—
4Coefficient of thermal expansion of BAg-8Printed as 19.6 x 10-6 per degC for 20 to 850 degC (also 10.9 x 10-6 per degF for 68 to 1562 degF)temperature range 20 to 850 °Calloy BAg-8, 72 wt% Ag and 28 wt% Cu—
50.2 percent offset yield strength of BAg-8Printed in the Physical Properties table; the data sheet says all values are indicative and based on test piecestest 0.2 percent offsettemper not stated on the data sheetform test pieces, not specified—
6Electrical resistivity of BAg-8Printed as 20.4 x 10-9 ohm m in the Physical Properties table, which equals 2.04 microohm cm; the conversion is not applied in this filealloy BAg-8, 72 wt% Ag and 28 wt% Cutemperature not stated—
7Melting range of silver-gold alloys AgAu 0.2 to AgAu 10Row values of the German silver-gold table, read from the printed PDF textalloys AgAu 0.2 (lowest) to AgAu 10 (highest), as listed in the tablebasis printed as melting range per alloy—
8Modulus of elasticity of soft silver-gold alloysRow values of the German silver-gold table, soft columntemper softalloys AgAu 0.2 to AgAu 10—
9Tensile strength of soft silver-gold alloysRow values of the German silver-gold table, soft column; the table gives a tolerance of plus or minus 30 MPa that is not enteredtemper softalloys AgAu 0.2 to AgAu 10—
10Tensile strength of hard silver-gold alloysRow values of the German silver-gold table, hard column; the table gives a tolerance of plus or minus 30 MPa that is not enteredtemper hardalloys AgAu 0.2 to AgAu 10—

Corrosion and compatibility

What happens when it meets other materials and environments.

Corrosion and compatibility
EnvironmentConcernWhat happens
Sulphur-bearing air (tarnish) not rated No tarnish rate for any silver alloy in this family was read in this run.1
Low Earth orbit, silver-backed second-surface mirror (vapour-deposited silver under FEP, not an alloy) not rated After almost six years in low Earth orbit the silvered FEP mirror changed from a specular to a diffuse reflector.2
Corrosion details
#EnvironmentDetailsTest conditions
1 Sulphur-bearing air (tarnish) The Cusil, Aimtek and Heimerle + Meule data sheets give no corrosion, tarnish or sulphidation data. No sulphur test or rate for BAg-8, silver-gold, silver-antimony, silver-zirconium-copper or silver-palladium alloys was entered. basis absence of data in the three datasheets read in this run
2 Low Earth orbit, silver-backed second-surface mirror (vapour-deposited silver under FEP, not an alloy) The NASA LDEF analysis reports that after almost six years of exposure the silvered FEP second-surface mirror changed from a specular reflector to a diffuse one, by surface roughening that depended on atomic-oxygen fluence. The silver layer is about 1600 A of vapour-deposited silver behind the FEP film. The report does not give an erosion rate for a silver alloy. exposure about six years in low Earth orbit on LDEFmaterial silvered FEP Teflon thermal blanket, pure silver backingbasis reported appearance change, not a silver-alloy erosion yield

Risks and side effects

Hazards to people, what happens when a cell overheats, and how the material is handled and stored.

For people

No GHS classification for any alloy in this family was read in this run. The exposure limit for silver metal dust is the relevant control.

Dust
NIOSH and OSHA both set 0.01 mg/m3 as an 8-hour TWA for silver metal dust and soluble compounds, as Ag.
Acute exposure
NIOSH sets the IDLH at 10 mg Ag/m3, based on acute oral toxicity data in humans; no inhalation data were available for the IDLH.

If it fails

No failure record for these alloys was read in this run, so this group is left as a gap.

Gap
The Skylab braze shows silver-copper-lithium brazing in space, but no braze failure data are sourced here.

Handling and storage

Brazing
BAg-8 is brazed under vacuum at 10-5 mm Hg, in hydrogen or in an inert gas, according to the Cusil data sheet.
Impurities
The Cusil data sheet caps Zn and Cd at 0.001 percent and Pb and P at 0.002 percent.

Test details
The original wording and numbers from the sources, for readers who want them.

Handling and storage

  • Cusil data sheet: braze under a vacuum of 10-5 mm Hg, in hydrogen, or in an inert gas. Impurity limits are Zn below 0.001 percent, Cd below 0.001 percent, Pb below 0.002 percent, P below 0.002 percent and C below 0.01 percent.
  • Dust from silver metal is limited to 0.01 mg/m3 (as Ag) in air; keep dust and fume below that level in workplace air.

Supply and geography

How common the raw materials are and where they come from.

Silver

USGS: silver is primarily obtained as a byproduct from lead-zinc, copper and gold mines; polymetallic deposits account for more than two-thirds of US and world resources. World mine production was an estimated 26,000 tons in 2025 compared with 25,300 tons in 2024.

Top producers (2025)
Mexico 24.2%, Peru 13.8%, China 13.1%, Bolivia 5.8%, Chile 5.4%
Critical mineral lists
US: listed
Recycling
USGS: about 1,000 tons of silver was recovered from new and old scrap in 2025, about 11 percent of apparent consumption. Brazing and solder took about 3 percent of US silver use in 2025, electrical and electronics 25 percent, and photovoltaics 15 percent.
Substitutes
USGS: aluminum and rhodium may be used to replace silver in some applications; stainless steel, tantalum and titanium may replace silver in some surgical pins and plates.

Copper

Copper is the alloying metal in BAg-8 at 28 percent by weight. Its crust abundance was not read in this run.

Top producers (2025)
Chile 23%, Congo (Kinshasa) 13.9%, Peru 11.7%, China 7.8%, United States 4.3%
Critical mineral lists
US: listed
Recycling
USGS: about 30 percent of US copper supply came from scrap in 2025; brass and wire-rod mills accounted for about 80 percent of copper recovered from scrap.