Pt 999 denotes platinum with a minimum purity of 99.9% by weight, containing only trace impurities. It is considered near-pure elemental platinum and is widely used for bullion, investment products, laboratory reference materials, and high-temperature or corrosion-critical applications.
Pt 999 is not alloy-strengthened. Its physical and mechanical properties reflect the intrinsic behavior of pure platinum metal.
Strengthening & Metallurgical Behavior
Crystal Structure:
• Face-Centered Cubic (FCC)
Strengthening Mechanisms:
✔ Limited work hardening (cold deformation only)
✔ Grain-size effects from casting or rolling
❌ No solid-solution strengthening
❌ No precipitation or heat-treat hardening
Any mechanical strengthening arises solely from deformation, not chemical composition.
Metallurgical Characteristics
Microstructure:
• Single-phase platinum matrix
• Large equiaxed grains in cast form
• Very low dislocation density in annealed state
Casting Behavior:
• Excellent fluidity at high temperature
• Low shrinkage porosity due to high density
• Very clean grain boundaries
✔ Ideal for repeated remelting and refining
Refining & Processing Properties
Refining Route:
• Platinum ore or PGM concentrate
• Smelting → PGM matte
• Converter processing
• Chemical dissolution (chloride systems)
• Selective precipitation
• Reduction to platinum sponge
• Final melting and casting
Processing Notes:
• Requires temperatures above 1,800 °C
• Processed under vacuum or inert gas
• Easily recyclable with minimal metal loss
Available Forms
Bullion & Investment:
• Standard bullion bars
• Minted bars
• Coins and medallions
Industrial & Technical:
• Sheet, foil, and wire
• Crucibles
• Electrodes
• Laboratory reference standards
Applications
Investment & Bullion:
✔ Platinum bars and coins
✔ Long-term value storage
✔ Exchange-traded platinum products
Industrial:
✔ Catalyst substrates
✔ Chemical processing equipment
✔ Electronics and sensors
Scientific & Medical:
✔ Laboratory ware
✔ Medical device components
✔ Reference materials
Key Characteristics
✔ Extremely high chemical purity
✔ Excellent corrosion resistance
✔ Outstanding thermal stability
✔ Highly ductile and malleable
✔ Easily remelted and refined
Advantages of Pt 999
✔ Highest platinum content outside ultra-pure grades
✔ Globally accepted bullion standard
✔ Minimal refining loss
✔ Chemically inert in most environments
✔ Excellent resale value and liquidity
Limitations
⚠ Soft and scratch-prone
⚠ Not suitable for durable jewellery
⚠ Higher price per gram
⚠ Requires careful handling and storage
Pt 999 vs Other Platinum Grades
| Grade | Pt Content | Primary Use |
|---|---|---|
| Pt 999 | 99.90% | Bullion, laboratory |
| Pt 950 | 95% | Jewellery |
| Pt 900 | 90% | Durable jewellery |
| Pt 850 | 85% | Industrial |
| Pt 800 | 80% | Budget alloys |
Why Choose Pt 999
Pt 999 is chosen when maximum platinum purity, chemical inertness, recyclability, and intrinsic metal value are the priority. While mechanically soft, its near-pure composition makes it the preferred grade for platinum bullion, refining feedstock, and high-integrity industrial and laboratory applications.