18K Yellow Gold (Au-12.5Cu-12.5Ag) vs Pure Gold (Au 99.99%)
Property comparison of 18K Yellow Gold (Au-12.5Cu-12.5Ag) and Pure Gold (Au 99.99%), both precious metal.
| Property | 18K Yellow Gold (Au-12.5Cu-12.5Ag) | Pure Gold (Au 99.99%) | Difference |
|---|---|---|---|
| Tensile strength | 300 MPa | 130 MPa | -57% |
| Elastic modulus | 75,000 MPa | 78,000 MPa | +4% |
| Density | 15,500 kg/m³ | 19,300 kg/m³ | +25% |
| Thermal conductivity | 320 W/m·K | 314 W/m·K | -2% |
| Specific heat | 200 J/kg·K | 130 J/kg·K | -35% |
| Coefficient of thermal expansion | 0.000014 1/K | 0.000014 1/K | -1% |
| Melting point | 912 °C | 1,063 °C | +17% |
Difference is Pure Gold (Au 99.99%) relative to 18K Yellow Gold (Au-12.5Cu-12.5Ag). Values are taken from the representative row of each material; both materials may have multiple heat treatments or conditions on their individual pages.
Identification
- grade
- 18K yellow
- standard
- Smithells Metals Reference Book 8th Ed.
- heat treatment
- annealed
- grade
- 24K / fine gold
- standard
- CRC Handbook of Chemistry and Physics
- heat treatment
- annealed
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