Pt 900 refers to a platinum alloy containing 90% platinum by weight, with the remaining 10% composed of alloying elements such as iridium, ruthenium, cobalt, copper, or palladium depending on the intended application.
Pt 900 is not a bullion grade. It is an engineered platinum alloy specifically designed to enhance mechanical strength, wear resistance, and formability while retaining platinum’s exceptional corrosion resistance.
Strengthening & Metallurgical Behavior
Primary Strengthening Mechanisms
✔ Solid-solution strengthening (Ir, Ru, Co distort Pt lattice)
✔ Work hardening during forging, rolling, and forming
✔ Grain refinement (especially Ru- and Co-containing alloys)
Crystal Structure: FCC platinum-based matrix
❌ No precipitation hardening
❌ No heat-treatment hardening beyond stress relief
Metallurgical Characteristics
Microstructure
• Single-phase platinum-rich matrix
• Fine, uniform grains (Ru & Co alloys)
• Very low porosity
| Alloy System | Casting Quality |
|---|---|
| Pt–Ir | Excellent |
| Pt–Ru | Excellent |
| Pt–Co | Very Good |
| Pt–Pd | Good |
| Pt–Cu | Moderate |
Refining & Processing Properties
Manufacturing Steps
• High-purity platinum sponge refining
• Alloying under vacuum or inert atmosphere
• Induction or arc melting
• Casting into billets
• Hot forging or rolling
• Cold working and annealing
Processing Notes
• Requires high-temperature equipment
• Sensitive to oxygen contamination (especially Co alloys)
• Annealing at 1,000–1,200 °C restores ductility
Available Forms
✔ Jewellery blanks
✔ Wire
✔ Sheet & strip
✔ Rings & bands
✔ Industrial components
✔ Medical & dental parts
Applications
Jewellery: Wedding bands, high-end rings, chains, luxury watch components
Industrial: Electrical contacts, thermocouple sheaths, precision springs, chemical equipment
Medical & Dental: Dental crowns, surgical components, implantable parts
Key Characteristics
✔ High platinum content
✔ Enhanced hardness versus pure platinum
✔ Retains platinum’s corrosion resistance
✔ Excellent surface finish
✔ Long service life
Advantages of Pt 900
✔ More durable than Pt 950 or Pt 999
✔ Lower cost than higher-purity platinum grades
✔ Superior wear resistance
✔ Easier to machine than pure platinum
✔ Ideal balance of purity and strength
Limitations
⚠ Slightly lower whiteness than Pt 950
⚠ Lower intrinsic platinum value
⚠ Not accepted as bullion or investment-grade metal
⚠ Alloy choice affects recyclability
Pt 900 vs Other Platinum Grades
| Grade | Platinum % | Typical Use |
|---|---|---|
| Pt 999 | 99.90% | Bullion, laboratory |
| Pt 950 | 95% | Premium jewellery |
| Pt 900 | 90% | Durable jewellery |
| Pt 850 | 85% | Industrial |
| Pt 800 | 80% | Budget jewellery |
Why Choose Pt 900
Pt 900 is selected when mechanical durability and wear resistance are more important than maximum purity. Its engineered alloy design provides excellent long-term performance in jewellery, medical, and precision industrial applications where deformation resistance and surface durability are critical.