Pt 850 is a platinum alloy containing 85% platinum by weight, with the remaining 15% composed of strengthening alloying elements such as iridium, ruthenium, cobalt, palladium, copper, or nickel—depending on manufacturer and application requirements.
Pt 850 is not an investment or bullion grade. It is an engineered functional platinum alloy designed for enhanced strength, wear resistance, and cost efficiency.
Strengthening & Metallurgical Behavior
Strengthening Mechanisms:
✔ Solid-solution strengthening due to high alloy fraction
✔ Work hardening during forming and finishing
✔ Grain refinement (notably in Pt–Ru and Pt–Co systems)
Crystal Structure:
• FCC platinum-rich matrix
• Lattice distortion due to heavy alloying
❌ No precipitation hardening
❌ Limited response to annealing
Metallurgical Characteristics
Microstructure:
• Fine, dense grains
• Single-phase or near single-phase matrix
• Low porosity
Fabrication Behavior
| Alloy System | Workability |
|---|---|
| Pt–Ir | Good |
| Pt–Ru | Very Good |
| Pt–Co | Good |
| Pt–Pd | Moderate |
| Pt–Cu / Pt–Ni | Moderate – Good |
Higher alloy content increases strength but reduces ductility.
Refining & Processing Properties
Manufacturing Steps:
• Platinum sponge refining
• Alloying under vacuum or inert atmosphere
• High-temperature melting (>1,700 °C)
• Casting or rolling
• Cold working and controlled annealing
Processing Notes:
• More difficult to polish than Pt 950
• Requires skilled welding and repair
• Pt–Co alloys show oxidation sensitivity
Available Forms
• Jewellery castings
• Sheet and strip
• Wire
• Mechanical and industrial components
Applications
Jewellery:
✔ High-durability rings
✔ Men’s jewellery
✔ Commercial jewellery lines
Industrial:
✔ Wear-resistant electrical contacts
✔ Springs, clips, and mechanical parts
✔ Chemical processing components
Medical & Technical:
✔ Dental and surgical components (non-implant)
✔ Specialized technical parts
Key Characteristics
✔ High mechanical strength
✔ Lower cost than Pt 900 and Pt 950
✔ Excellent wear resistance
✔ Retains platinum corrosion resistance
✔ Functional, long-life alloy
Advantages of Pt 850
✔ Stronger than Pt 900 and Pt 950
✔ Reduced deformation and scratching
✔ Cost-effective platinum grade
✔ Suitable for demanding environments
✔ Good machinability (alloy dependent)
Limitations
⚠ Lower platinum content
⚠ Reduced ductility
⚠ Slightly darker color
⚠ Limited global hallmark acceptance
⚠ Not suitable for bullion or investment
Pt 850 vs Other Platinum Grades
| Grade | Platinum % | Primary Use |
|---|---|---|
| Pt 999 | 99.90% | Bullion |
| Pt 950 | 95% | Fine jewellery |
| Pt 900 | 90% | Durable jewellery |
| Pt 850 | 85% | Functional / industrial |
| Pt 800 | 80% | Entry-level alloys |
Why Choose Pt 850
Pt 850 is selected when mechanical strength, wear resistance, and cost efficiency outweigh the need for maximum platinum purity. It is ideal for high-stress jewellery and industrial applications where platinum identity must be retained without the cost and softness of higher-purity grades.