Precious Metal Pt95Co5
Pt95Co5 is a 950-fine platinum alloy hardened with 5 % cobalt, the standard investment-casting composition for platinum jewelry.
Reference datasheet — Pt95Co5 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 AC condition
Pt95Co5 tempers and conditions
Pt95Co5 is supplied in 5 conditions, soft to hard. AC is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Choose the annealed soft state before or after cold working sheet, wire and tube; 32% elongation suits hand forging, drawing and bezel setting, at only 190 MPa yield. | 190 | 430 | 32 | 124 HB | 7 % IACS |
ACDefault Spheroidize annealed | Pick the normal as-investment-cast delivery state for lost-wax jewellery blanks: fine grain and good density allow direct filing and polishing, with 20% elongation. | 250 | 480 | 20 | 128 HB | 7 % IACS |
Quarter hard | Use lightly cold-worked (about 15%) sheet or wire for ring shanks and light structural parts that must balance formability against resistance to deformation. | 400 | 550 | 15 | 152 HB | 6.8 % IACS |
Half hard | Pick half-hard stock cold worked about 30–35% for prongs, clasps and chain parts needing rigidity; 520 MPa yield comes with elongation reduced to 8%. | 520 | 640 | 8 | 10 HRC | 6.8 % IACS |
Full hard | Choose heavily cold-worked wire or strip (50%+ reduction) for spring clasps and earring posts where hardness and springiness are highest; elongation drops to 3%. | 620 | 720 | 3 | 18 HRC | 6.7 % IACS |
Supply forms, finishes and certifications
Ways Pt95Co5 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
GRAIN | Casting Grain | Surface finish |
What is Pt95Co5?
Pt95Co5 is a 950-fine platinum alloy hardened with 5 % cobalt, the standard investment-casting composition for platinum jewelry. It fills fine detail and gives 250 MPa yield, 480 MPa tensile and 20 % elongation, and is available as-cast, annealed, in H01–H04 tempers and as casting grain. Formability (score 55) and machinability (score 35) are only moderate, and it work-hardens faster than Pt95Ru5, which remains the choice for deep-drawn or spring parts. Cobalt oxidizes if the alloy is overheated in air during torch work. Pt95Co5 has a density of 20 g/cm³ (0.723 lb/in³), heavier than 93% of precious metal grades. It melts at 1,745°C (3,173 °F). Pt95Co5 has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 480 MPa (69.6 ksi) — stronger than 81% of precious metal grades. Elongation at break is 20% and the elastic modulus is 168 GPa (24.4 Msi).
What is Pt95Co5 used for?
- Cast platinum jewelry
- Ring settings
- Watch cases
Advantages
- Readily welded — 85/100, better than 93% of precious metal grades
- High service temperature — 800°C (1,472 °F), better than 90% of precious metal grades
- Stiff — 168 GPa (24.4 Msi), better than 89% of precious metal grades
- Good corrosion resistance — 96/100, better than 85% of precious metal grades
- High strength — 250 MPa (36.3 ksi), better than 81% of precious metal grades
Limitations
- Heavy — 20 g/cm³ (0.723 lb/in³), worse than 93% of precious metal grades
- Poor heat conductor — 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 89% of precious metal grades
- Low electrical conductivity — 7 % IACS, worse than 89% of precious metal grades
- Limited formability — 55/100, worse than 89% of precious metal grades
- High embodied carbon — 13,000 kg CO₂/kg, worse than 81% of precious metal grades
Pt95Co5 properties
Typical room-temperature values for Pt95Co5-AC; bars are the position among precious metal grades.
Physical3
Pt95Co5 has a density of 20 g/cm³ (0.723 lb/in³), heavier than 93% of precious metal grades. It melts at 1,745°C (3,173 °F).
Mechanical14
Pt95Co5 has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 480 MPa (69.6 ksi) — stronger than 81% of precious metal grades. Elongation at break is 20% and the elastic modulus is 168 GPa (24.4 Msi).
Thermal6
Pt95Co5 is rated for continuous service to 800°C (1,472 °F). It conducts heat at 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 89% of precious metal grades. Thermal expansion is 9.2 µm/m·K (5.11 µin/in·°F).
Electrical3
Pt95Co5 conducts electricity at 7 % IACS, worse than 89% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (96/100), better than 85% of precious metal grades.
Sustainability4
Producing a kilogram of Pt95Co5 takes about 250,000 MJ of energy and emits 13,000 kg of CO₂ — more than 95% of precious metal grades. Typical recycled content is 35%.
Manufacturability8
Pt95Co5's machinability is fair (35/100, worse than 73% of precious metal grades); weldability excellent (85/100); formability good (55/100).
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. Pt95Co5 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Pt95Co5
Is Pt95Co5 easy to machine?
Tough and gummy with a tendency to build-up edge — use sharp, high positive-rake carbide or diamond tooling at low speed with light feeds and ample lubricant. Single-point diamond turning gives a mirror surface on jewelry parts.
Can Pt95Co5 be welded?
Laser and PUK pulse-arc welding work well with matching Pt950Co filler wire. With oxy-acetylene, keep the flame slightly reducing to limit cobalt oxidation and avoid overheating, which coarsens the grain.
Can Pt95Co5 be formed, bent or molded?
Investment casting is the primary route: mould temperature 850–1000 °C, pour at 1800–1850 °C, induction vacuum or centrifugal. Castings can be annealed and cold formed; interanneal once cold work exceeds about 40 %.
Pt95Co5 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 |
|---|---|---|
| Cosolid-solution strengthener; casting flow, fine grain, weak magnetism | 4.5 – 5.5 | 5 |
| Other (Ir, Ru, Cu, Fe )total impurities, normally well below 0.1% | ≤ 0.5 | |
| Pt950 hallmark requires ≥95.0% Pt (GB 11887 / ISO 9202) | ≥ 95 (balance) |
What surface finishes work on Pt95Co5?
Polishes more quickly than Pt950Ru; step through silicon carbide, then alumina, then chromium oxide for a mirror finish. Rhodium plating is not required, though a thin rhodium flash can be applied for an extra-white tone; blasted and brushed textures remain stable and do not tarnish.
Equivalent designations
Standards and trade names that resolve to Precious Metal Pt95Co5 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- Pt950CoPtCo5
How much does Pt95Co5 cost?
Pt95Co5 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.
Pt95Co5 — frequently asked
What is Pt95Co5 used for?
Pt95Co5 is typically used for cast platinum jewelry, ring settings and watch cases. In short: standard platinum casting alloy; fast-polishing Pt950 grade; bright white at 950 fineness.
What is the yield strength of Pt95Co5?
Pt95Co5 has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 480 MPa (69.6 ksi) — stronger than 81% of precious metal grades. Strength varies by condition: see the 5 listed tempers.
Is Pt95Co5 easy to machine?
Not especially — machinability is rated fair (35/100, worse than 73% of precious metal grades). Tough and gummy with a tendency to build-up edge — use sharp, high positive-rake carbide or diamond tooling at low speed with light feeds and ample lubricant. Single-point diamond turning gives a mirror surface on jewelry parts.
Can Pt95Co5 be welded?
Yes — weldability is rated excellent (85/100). Laser and PUK pulse-arc welding work well with matching Pt950Co filler wire. With oxy-acetylene, keep the flame slightly reducing to limit cobalt oxidation and avoid overheating, which coarsens the grain.
What surface finishes work on Pt95Co5?
Polishes more quickly than Pt950Ru; step through silicon carbide, then alumina, then chromium oxide for a mirror finish. Rhodium plating is not required, though a thin rhodium flash can be applied for an extra-white tone; blasted and brushed textures remain stable and do not tarnish.
Can Pt95Co5 be formed, bent or molded?
Investment casting is the primary route: mould temperature 850–1000 °C, pour at 1800–1850 °C, induction vacuum or centrifugal. Castings can be annealed and cold formed; interanneal once cold work exceeds about 40 %.
What is the maximum service temperature of Pt95Co5?
Pt95Co5 is rated for continuous use to about 800°C (1,472 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Pt95Co5-AC and Pt95Co5-H04?
AC is the default condition — pick the normal as-investment-cast delivery state for lost-wax jewellery blanks: fine grain and good density allow direct filing and polishing, with 20% elongation. H04: choose heavily cold-worked wire or strip (50%+ reduction) for spring clasps and earring posts where hardness and springiness are highest; elongation drops to 3%. Yield strength is 250 MPa in AC versus 620 MPa in H04.
How much does Pt95Co5 cost?
Pt95Co5 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
- ISO 9202 Jewellery — Fineness of precious metal alloys — ISO (2019)
- Platinum Metals Review — platinum jewellery alloys (properties of Pt-Co, Pt-Ru, Pt-Ir) — Johnson Matthey (2005)
- ASM Handbook Vol. 2 — Properties of Precious Metals and Alloys — ASM International (1990)
- Platinum casting alloy technical data (Pt950/Co) — Hoover & Strong / Stuller (2023)
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.