Precious Metal 80Ag-20CdO-IO (Internally oxidized)
Grade
ASTM B268
Use where the finest, gradient CdO dispersion and lowest contact resistance are wanted on small/medium contactor tips.
Values for the IO condition
Other 80Ag-20CdO tempers and conditions
80Ag-20CdO is listed in 6 conditions; see the grade overview at 80Ag-20CdO.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Powder-metallurgical | Preferred for thick or large-section contacts where uniform CdO distribution through the full depth is required. | 125 | 260 | 14 | 68 HB | 70 % IACS |
ADefault Solution annealed | Default stock condition for cold-headed rivets, deep-drawn buttons and contacts brazed onto carriers. | 135 | 265 | 15 | 66 HB | 73 % IACS |
IOThis page Internally oxidized | Use where the finest, gradient CdO dispersion and lowest contact resistance are wanted on small/medium contactor tips. | 150 | 285 | 10 | 75 HB | 74 % IACS |
Quarter hard | Pick when stamped contacts need extra stiffness and burr-free blanking but still some forming reserve. | 215 | 300 | 8 | 80 HB | 71 % IACS |
Half hard | Middle-ground strip temper for progressive-die contacts that also carry mild spring load. | 255 | 325 | 5 | 90 HB | 70 % IACS |
Hardened | Choose for maximum mechanical wear and deformation resistance on blade/knife contacts and thin stamped tips. | 300 | 355 | 3 | 102 HB | 69 % IACS |
What is 80Ag-20CdO-IO?
80Ag-20CdO-IO is 80Ag-20CdO in the IO grade — use where the finest, gradient CdO dispersion and lowest contact resistance are wanted on small/medium contactor tips. 80Ag-20CdO-IO has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 285 MPa (41.3 ksi) — weaker than 68% of precious metal grades. Elongation at break is 10% and the elastic modulus is 86 GPa (12.5 Msi). 80Ag-20CdO-IO has a density of 9.9 g/cm³ (0.358 lb/in³), lighter than 70% of precious metal grades. It melts at 961°C (1,762 °F). A is the default condition FabDigit quotes; IO is available on request or by drawing note.
Advantages
- High electrical conductivity — 74 % IACS, better than 77% of precious metal grades
- Conducts heat well — 310 W/m·K (179.1 BTU/hr·ft·°F), better than 76% of precious metal grades
Limitations
- Limited ductility — 10%, worse than 89% of precious metal grades
- Limited formability — 58/100, worse than 87% of precious metal grades
- Hard to polish — 70/100, worse than 76% of precious metal grades
80Ag-20CdO-IO properties
Typical room-temperature values for 80Ag-20CdO-IO; 18 are specific to this condition. Other listed values are 80Ag-20CdO reference data and may not represent this condition. Bars are the position among precious metal grades.
Physical3
80Ag-20CdO-IO has a density of 9.9 g/cm³ (0.358 lb/in³), lighter than 70% of precious metal grades. It melts at 961°C (1,762 °F).
Mechanical11
80Ag-20CdO-IO has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 285 MPa (41.3 ksi) — weaker than 68% of precious metal grades. Elongation at break is 10% and the elastic modulus is 86 GPa (12.5 Msi).
Thermal6
80Ag-20CdO-IO is rated for continuous service to 250°C (482 °F). It conducts heat at 310 W/m·K (179.1 BTU/hr·ft·°F), better than 76% of precious metal grades. Thermal expansion is 18 µm/m·K (10 µin/in·°F).
Electrical3
80Ag-20CdO-IO conducts electricity at 74 % IACS, better than 77% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (86/100), better than 66% of precious metal grades.
Sustainability3
Producing a kilogram of 80Ag-20CdO-IO takes about 1,450 MJ of energy and emits 130 kg of CO₂ — less than 54% of precious metal grades. Typical recycled content is 45%.
Manufacturability8
80Ag-20CdO-IO's machinability is fair (48/100, better than 71% of precious metal grades); weldability fair (35/100); formability good (58/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 80Ag-20CdO-IO
Is 80Ag-20CdO easy to machine?
Turns and blanks readily but the silver matrix smears — use sharp carbide, high speed, light feed and generous coolant; capture all CdO-bearing swarf as toxic waste.
Can 80Ag-20CdO be welded?
Not fusion welded as a joint material; contacts are resistance-welded or induction/torch brazed to Cu or CuZn carriers, ideally through a fine-silver or AgCu backing layer.
Can 80Ag-20CdO be formed, bent or molded?
Supplied soft it cold-heads, deep-draws and stamps well; work-hardened tempers need an intermediate anneal at 500–600 °C in a neutral atmosphere to avoid cracking.
What surface finishes work on 80Ag-20CdO?
No anodizing; contact faces are usually left as-machined or lightly polished, backs may be Ag- or AgCu-clad for brazing, and sulfur-bearing packaging/rubbers must be avoided to prevent tarnish.
80Ag-20CdO chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CdOcadmium oxide dispersoid; equivalent to ≈17.5 % Cd + 2.5 % O | 18.5 – 21.5 | 20 |
| Other (total impurities)Cu, Fe, Pb, Ni etc. per ASTM B692 | ≤ 0.15 | — |
| Agsilver matrix, 99.95 % min purity before oxidation | ≥ 78.5 (balance) | — |
80Ag-20CdO-IO — frequently asked
What is 80Ag-20CdO-IO used for?
80Ag-20CdO-IO is typically used for contactor contacts, circuit breaker contacts and motor starter contacts. In short: highest CdO loading offered; strongest Ag-CdO grade; best arc-quenching in family.
What is the yield strength of 80Ag-20CdO-IO?
80Ag-20CdO-IO has a typical yield strength of 150 MPa (21.8 ksi) and a tensile strength of 285 MPa (41.3 ksi) — weaker than 68% of precious metal grades. Strength varies by condition: see the 6 listed tempers.
Is 80Ag-20CdO-IO easy to machine?
Reasonably — machinability is rated fair (48/100, better than 71% of precious metal grades). Turns and blanks readily but the silver matrix smears — use sharp carbide, high speed, light feed and generous coolant; capture all CdO-bearing swarf as toxic waste.
Can 80Ag-20CdO-IO be welded?
With care — weldability is rated fair (35/100). Not fusion welded as a joint material; contacts are resistance-welded or induction/torch brazed to Cu or CuZn carriers, ideally through a fine-silver or AgCu backing layer.
What surface finishes work on 80Ag-20CdO-IO?
No anodizing; contact faces are usually left as-machined or lightly polished, backs may be Ag- or AgCu-clad for brazing, and sulfur-bearing packaging/rubbers must be avoided to prevent tarnish.
Can 80Ag-20CdO-IO be formed, bent or molded?
Supplied soft it cold-heads, deep-draws and stamps well; work-hardened tempers need an intermediate anneal at 500–600 °C in a neutral atmosphere to avoid cracking.
What is the maximum service temperature of 80Ag-20CdO-IO?
80Ag-20CdO-IO is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 80Ag-20CdO-A and 80Ag-20CdO-H?
A is the default condition — default stock condition for cold-headed rivets, deep-drawn buttons and contacts brazed onto carriers. H: choose for maximum mechanical wear and deformation resistance on blade/knife contacts and thin stamped tips. Yield strength is 135 MPa in A versus 300 MPa in H.
Sources
- ASTM B692 — Standard Specification for Silver-Cadmium Oxide Electrical Contact Material — ASTM International (2018)
- Data Book of Electrical Contacts — DODUCO / AMI DODUCO (2012)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Electrical Contact Materials) — ASM International (1990)
- Silver-metal-oxide contact material datasheets (AgCdO grades) — Metalor / Umicore Technical Materials (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.