Tungsten Carbide
Sintered carbide composite
Gunmetal grey to polished dark silver. Extremely high polish possible; can be coated in black, gold-tone, or other finishes
Composition
Typically 85–95% tungsten carbide (WC) sintered with cobalt (Co) or nickel (Ni) binder
Physical properties
| Density | 15.20 g/cm³ | Weight per unit volume. Platinum is ~40% heavier than 18k gold at equal size |
|---|---|---|
| Melting range | 2600–2870 °C | Working temperature for alloys. Pure metals have a sharp melting point |
| Vickers hardness | 1600 HV | Higher HV = greater scratch resistance in service |
| Mohs hardness | 9.2 | Approximate equivalent for comparative reference |
| Tensile strength | 700 MPa | Resistance to breaking under tension, relevant for prongs and fine settings |
| Tarnish resistance | Excellent | Surface oxidation / sulphidation under typical wear conditions |
| Workability | Poor | Ease of forming, soldering, and fabricating under standard jewellery workshop conditions |
| Hypoallergenic | Partial risk | Likelihood of triggering skin reactions under normal wear |
Common uses
Men's wedding bands, industrial cutting tools, drill bits, mining equipment
Hallmarking & identification
No precious metal hallmark. May be marked 'Tungsten Carbide' or 'TC'. Not a pure metal; it is a ceramic-metal composite (cermet). Cannot be resized; rings must be cut off in emergencies (requires diamond-tipped cutting tools).
Virtually scratch-proof under normal conditions. Clean with warm soapy water. Avoid dropping on hard surfaces; although extremely hard, tungsten carbide is brittle and can crack or shatter. Cobalt-binder variants may oxidise with prolonged skin contact; choose nickel-binder for better biocompatibility.
Market & pricing
Very low raw material cost. Mid-range retail pricing driven by machining and finishing. Dramatically less expensive than precious metal rings of equivalent appearance.