Chemical Composition
| NGK Alloy | Chemical Composition [wt%] | |
|---|---|---|
| Alloy 25 | Be Ni+Co Ni+Co+Fe Cu+Be+Ni+Co+Fe |
1.80-2.00 0.20min. 0.6max. 99.5min. |
| Alloy 8 Alloy 11 |
Be Ni Cu+Be+Ni |
0.20-0.60 1.40-2.20 99.5min. |
| Alloy 7 | Be Ni+Co Al Cu+Be+Ni+Co+Al |
0.20-0.40 1.80-2.50 0.6max. 99.0min. |
The chemical composition of beryllium copper alloys is tested using optical atomic emission spectrometry as specified by NGK. Cu is considered the remainder after subtracting other elements.
Physical Properties
| Item | NGK Alloy 25 | NGK Alloy 8·11 | NGK Alloy 7 |
|---|---|---|---|
| Melting Point (solidus) [℃] | 865 | 1004 | 1050 |
| Melting Point (liquidus) [℃] | 980 | 1070 | 1081 |
| Density [g/cm3] at 20℃ |
8.36 | 8.82 | 8.71 |
| Specific Heat [J/(kg・K)] at 20℃ |
419 | 419 | 419 |
| Thermal Expansion Coefficient [/℃] at 20〜300℃ |
17.8×10-6 | 17.6×10-6 | 17.6×10-6 |
| Modulus of Elasticity [kN/mm2] | 127 | 132 | 127 |
| Modulus of Rigidity [kN/mm2] | 49 | 52 | 49 |
| Poidon’s Ratio | 0.3 | 0.3 | 0.3 |
| Magnetic Permeability [μ(μ=1+4πk)] | 1.000042 | 1.000031 | 1.000027 |
Electrical conductivity and thermal conductivity * （at 20℃）
| NGK Alloy 25 | NGK Alloy 8 | NGK Alloy 11 | NGK Alloy 7 | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Age Hardenable | Mill hardened | 8-1/2HT | 8-HT | 11-HT | 11-SHC | 7-1/2HT | 7-HT | 7-EHT | |
| Thermal conductivity [W/(m・K)] | 99 | 85 | 298 | 280 | 262 | 221 | 194 | 180 | 176 |
| Electrical conductivity [%IACS] | 24 | 21 | 68 | 64 | 60 | 51 | 45 | 42 | 41 |
