Precious Metal 85Pt-15Ir
85Pt-15Ir is a solid-solution-hardened platinum alloy with 15% iridium, supplied in O, 1/2H and H tempers as wire, strip and contact tips.
Reference datasheet — 85Pt-15Ir is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the O condition
85Pt-15Ir tempers and conditions
85Pt-15Ir is supplied in 3 conditions, soft to hard. O is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ODefault Annealed | Choose for wire drawing, coiling, deep forming, electrode fabrication and welded assemblies where maximum ductility is needed. | 200 | 480 | 27 | 84 HRB | 6.2 % IACS |
Half hard | Compromise temper for contact rivets, blanked contact discs and light spring members that still need some bend ductility. | 500 | 700 | 8 | 20 HRC | 6 % IACS |
Hardened | Choose for slip-ring brushes, potentiometer wiper wire, spring contacts and probe tips needing maximum hardness and wear life. | 800 | 965 | 3 | 28 HRC | 5.4 % IACS |
What is 85Pt-15Ir?
85Pt-15Ir is a solid-solution-hardened platinum alloy with 15% iridium, supplied in O, 1/2H and H tempers as wire, strip and contact tips. Engineers use it where a contact must stay clean and dimensionally stable for the life of the device: hardness is 84 HRB with 480 MPa tensile strength, 27% elongation, 205 GPa modulus, and it resists tarnish and oxidation to 1000 °C. Electrical conductivity is only 6.2% IACS and thermal conductivity 26 W/m·K, so it is restricted to low-current precision contacts rather than power switching, and cost is high. 90Pt-10Ir is the softer, more drawable alternative. 85Pt-15Ir has a density of 21.6 g/cm³ (0.78 lb/in³), heavier than 100% of precious metal grades. It melts at 1,790°C (3,254 °F). 85Pt-15Ir has a yield strength of 200 MPa (29 ksi) and a tensile strength of 480 MPa (69.6 ksi) — stronger than 51% of precious metal grades. Elongation at break is 27% and the elastic modulus is 205 GPa (29.7 Msi).
What is 85Pt-15Ir used for?
- precision instrument contacts
- slip rings
- spark igniter electrodes
Advantages
- Stiff — 205 GPa (29.7 Msi), better than 98% of precious metal grades
- Good corrosion resistance — 100/100, better than 98% of precious metal grades
- High service temperature — 1,000°C (1,832 °F), better than 95% of precious metal grades
Limitations
- Heavy — 21.6 g/cm³ (0.78 lb/in³), worse than 100% of precious metal grades
- High embodied carbon — 16,000 kg CO₂/kg, worse than 96% of precious metal grades
- Poor heat conductor — 26 W/m·K (15 BTU/hr·ft·°F), worse than 95% of precious metal grades
- Difficult to machine — 25/100, worse than 94% of precious metal grades
- Low electrical conductivity — 6.2 % IACS, worse than 91% of precious metal grades
85Pt-15Ir properties
Typical room-temperature values for 85Pt-15Ir-O; bars are the position among precious metal grades.
Physical3
85Pt-15Ir has a density of 21.6 g/cm³ (0.78 lb/in³), heavier than 100% of precious metal grades. It melts at 1,790°C (3,254 °F).
Mechanical11
85Pt-15Ir has a yield strength of 200 MPa (29 ksi) and a tensile strength of 480 MPa (69.6 ksi) — stronger than 51% of precious metal grades. Elongation at break is 27% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
85Pt-15Ir is rated for continuous service to 1,000°C (1,832 °F). It conducts heat at 26 W/m·K (15 BTU/hr·ft·°F), worse than 95% of precious metal grades. Thermal expansion is 8.6 µm/m·K (4.78 µin/in·°F).
Electrical3
85Pt-15Ir conducts electricity at 6.2 % IACS, worse than 91% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (100/100), better than 98% of precious metal grades.
Sustainability4
Producing a kilogram of 85Pt-15Ir takes about 260,000 MJ of energy and emits 16,000 kg of CO₂ — more than 98% of precious metal grades. Typical recycled content is 40%.
Manufacturability8
85Pt-15Ir's machinability is poor (25/100, worse than 94% of precious metal grades); weldability very good (70/100); formability very good (70/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the precious metal family
Yield strength against density for every precious metal grade FabDigit runs. 85Pt-15Ir is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 85Pt-15Ir
Is 85Pt-15Ir easy to machine?
Machines like a gummy, rapidly work-hardening noble alloy — sharp carbide or diamond tooling, low speed, heavy positive rake, continuous flood coolant, and always collect the chips as refinable scrap.
Can 85Pt-15Ir be welded?
Excellent for resistance, micro-TIG and laser welding to itself, Pt and PtIr electrodes; avoid contact with molten base metals (Fe, Ni, Cu) which embrittle the joint.
Can 85Pt-15Ir be formed, bent or molded?
Anneal at 900–1100 °C in air or clean atmosphere between drawing/rolling passes; annealed material draws to fine wire readily, hard temper needs generous bend radii.
85Pt-15Ir 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 |
|---|---|---|
| Irsolid-solution hardener | 14.5 – 15.5 | 15 |
| Other (Pd+Rh+Ru+Au+base metals, total)impurity total for contact/electrode quality material | ≤ 0.15 | 0.05 |
| Ptbalance, 99.95 % pure base metal | ≥ 84.4 (balance) |
What surface finishes work on 85Pt-15Ir?
No plating or anodising required — electropolish or mechanically polish to a mirror surface; the alloy will not tarnish, so contact resistance stays stable without any coating.
Equivalent designations
Standards and trade names that resolve to Precious Metal 85Pt-15Ir in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- Pt85-Ir15
How much does 85Pt-15Ir cost?
85Pt-15Ir is a high-cost precious metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
85Pt-15Ir — frequently asked
What is 85Pt-15Ir used for?
85Pt-15Ir is typically used for precision instrument contacts, slip rings and spark igniter electrodes. In short: hardest common Pt-Ir grade; tarnish-free to 1000 °C; very low electrical conductivity.
What is the yield strength of 85Pt-15Ir?
85Pt-15Ir has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 480 MPa (69.6 ksi) — stronger than 51% of precious metal grades. Strength varies by condition: see the 3 listed tempers.
Is 85Pt-15Ir easy to machine?
Not especially — machinability is rated poor (25/100, worse than 94% of precious metal grades). Machines like a gummy, rapidly work-hardening noble alloy — sharp carbide or diamond tooling, low speed, heavy positive rake, continuous flood coolant, and always collect the chips as refinable scrap.
Can 85Pt-15Ir be welded?
Yes — weldability is rated very good (70/100). Excellent for resistance, micro-TIG and laser welding to itself, Pt and PtIr electrodes; avoid contact with molten base metals (Fe, Ni, Cu) which embrittle the joint.
What surface finishes work on 85Pt-15Ir?
No plating or anodising required — electropolish or mechanically polish to a mirror surface; the alloy will not tarnish, so contact resistance stays stable without any coating.
Can 85Pt-15Ir be formed, bent or molded?
Anneal at 900–1100 °C in air or clean atmosphere between drawing/rolling passes; annealed material draws to fine wire readily, hard temper needs generous bend radii.
What is the maximum service temperature of 85Pt-15Ir?
85Pt-15Ir is rated for continuous use to about 1,000°C (1,832 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 85Pt-15Ir-O and 85Pt-15Ir-H?
O is the default condition — choose for wire drawing, coiling, deep forming, electrode fabrication and welded assemblies where maximum ductility is needed. H: choose for slip-ring brushes, potentiometer wiper wire, spring contacts and probe tips needing maximum hardness and wear life. Yield strength is 200 MPa in O versus 800 MPa in H.
How much does 85Pt-15Ir cost?
85Pt-15Ir is a high-cost precious metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM B684 — Platinum-Iridium Electrical Contact Material — ASTM International (2020)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Precious Metals) — ASM International (1990)
- Platinum-Iridium Alloy Technical Data (Pt-10Ir / Pt-15Ir / Pt-20Ir) — Johnson Matthey Noble Metals (2021)
- Precious Metal Alloys for Electrical Contacts and Medical Electrodes — Heraeus (2022)
- Platinum Metals Review — physical properties of Pt-Ir solid solutions — Johnson Matthey (2014)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.