Choosing between an Indium seal and an Indium Silver seal depends on specific requirements. Here are some considerations:
Physical Properties
| Solder Alloy | 97In3Ag by wt% | 90In10Ag by wt% | 100% Indium |
| Solidus (°C) | 143 | 143 | 156 |
| Liquidus (°C) | 143 | 237 | 156 |
| Density (gm/cm3) | 7.38 | 7.54 | 7.31 |
| Tensile Strength (psi) | 1330 | 1364 | 386 |
| Thermal Conductivity (W/m⋅K) | 75 | 71 | 86 |
| Electrical Conductivity (µΩ⋅m) | 0.075 | 0.078 | 0.0837 |
Indium Seal (In):
Advantages: Pure Indium (In) seals are known for their excellent wetting properties on non-metallic surfaces like glass, quartz, and ceramics. They are highly effective in creating reliable hermetic seals in various environments.
Applications: Commonly used in high-vacuum systems, cryogenic applications, and where minimal outgassing and low vapor pressure are critical.
Indium Silver Seal (In97Ag3, In90Ag10):
Advantages: Indium Silver (InAg) seals combine the advantages of Indium with the added strength and improved mechanical properties provided by Silver (Ag). They offer enhanced tensile strength compared to pure Indium seals.
Applications: Suitable for applications where mechanical robustness and improved creep resistance are required, such as in electronic packaging, high-reliability semiconductor devices, and some aerospace applications.
Q&A:
- When should I choose an Indium Washer over an Indium Silver Washer?
Answer: Opt for an Indium Seal (In) when you need superior wetting properties and low vapor pressure, ideal for creating hermetic seals in environments demanding high purity and minimal outgassing.
- What advantages does an Indium Silver Seal offer over a pure Indium Seal?
Answer: An Indium Silver Seal (InAg) provides improved mechanical strength and creep resistance due to the addition of Silver. It is preferred in applications requiring stronger seals that can withstand higher mechanical stresses.
- In what applications are Indium Silver Seals typically used?
Answer: Indium Silver Seals (InAg) are commonly used in electronic packaging, where reliability under varying thermal and mechanical stresses is crucial. They are also favored in aerospace and other high-reliability applications where the seal’s mechanical integrity is paramount.