Which Is the Best Hermetic Seal: Glass or Ceramic?

If you are in the market for a hermetic seal, you may wonder if it is better to purchase a glass to metal seal or a ceramic to metal seal. Each variety has its respective advantages and disadvantages. Some people prefer to stick with one kind, while others use different seals depending on the function.

Glass to Metal Seal and Feedthrough

A glass to metal seal is made with glass molten right to the metal. This provides an advantage of a secure seal that is connected directly with the metal. Glass is thought of as fragile, but it has a high level of compression strength. It is also a less expensive alternative to ceramic seals.

Ceramic to Metal Seal

A ceramic to metal seal is more costly than a glass to metal seal, and some say the difference in price is worth it. Ceramic can be made in custom designs and show more resistance to mechanical and thermal shocks. However, these seals can have a greater tendency to chip than glass does, but can last longer before these chips form.

Some people swear by their favorite kind of glass to metal seal, while others prefer ceramic. The kind you choose depends on the job you need to do, cost considerations and how much shock you want the seal to withstand.

Understanding Hermetic Seal Types and Uses

A hermetic seal is known as a go-to choice for superior protection when it counts. Whether you require protection from air, gasses, moisture, soil or any other hazard, hermetic connections are the gold standards across many industries. But a seal protects best when it is the right seal for the job. Learn more about the main types of hermetic sealing and find out which ones are best for your job.

To start with, there are three main types of airtight seal. They are:

  • Glass to glass seal
  • Glass to metal seal
  • Ceramic to metal seal

Glass to Glass Hermetic Seals

When two glass pieces require a perfectly sealed environment, glass to glass sealing is the choice. As many as five layers may be involved in the creation this type of seal, which is often used in sealing flat windows, glass tube components and glass envelopes to name just a few applications.

Glass to Metal Seals

Glass and metal fused together to form leak-tight joints are glass to metal seals. These types of seals are all around you every day, due mainly to their versatility and strength.  Known for their exceptional hermetic values, these types of seals are critical in the construction of vacuum tubes, pressure tight glass windows and any number of electronic components to name just a few applications. GTMs are especially useful in the lighting industry, with the most common application being the seal on a lamp bulb.

 Ceramic to Metal Seals

Ceramic to Metal seal is more costly and time consuming to make than a glass to metal seal. Some say it is worth for applications where high operating temperatures, high voltage and harsh environments are required. Ceramic can be made in custom designs and show more resistance to mechanical and thermal shocks.

When zero porosity is required, hermetic sealing is the reliable choice. Know your options by understanding the different sealing possibilities and ensure you’re choosing the best sealing method.

3 Rules for Choosing Hermetic Packages

Whether in medical, military, aeronautic or any myriad of settings, failure of hermetic headers can have catastrophic outcomes. How can you ensure that your hermetic packages are up to the challenge of your unique hermeticity needs? Here are three ideas to ensure your devices won’t fail.

Hermeticity Testing

Hermeticity testing primarily involves either fine leak testing or gross leak testing. The former examines hermetic packages for defects that can lead to leakage, while the latter focuses on damage that can cause gross package leakage. Periodic testing is a good way to detect faults before a major incident.

Choose the Right Seal

The proper hermetic seals are key to preventing leakage. Glass to metal seals might be best for pressure-tight windows, while glass to glass might be better for glass tube components. When choosing hermetic headers and packages, consider the material you are sealing.

Pick an Experienced Manufacturer

The market for hermetic headers is a broad one and it can be difficult to know which manufacturers are ideal. A good rule of thumb is to find a manufacturer specializing in more than one type or market of hermetics. Choose a company offers a good mix of seal types with hermetic packages designed for various industries. Finally, look for one with a trusted name and years of experience to ensure hermetics you can depend on.

Hermetic Connectors Individuals

Hermetic Sealed Connectors: Customization Considerations

Hermetic sealed connectors are important in regards to system integrity maintenance. These connectors may be used in aerospace operations or military. They may be used in gas-tight barriers and may have to withstand extreme pressures. It’s important that you can optimize your connectors to match your requirements.

Environmental Factors 

To customize hermetics, you must consider harsh or hostile environments. Will your hermetic connectors be exposed to vibration, shock or thermal changes? You have to factor the environment and conditions into the design. You may also need to choose between different plating requirements. You can choose from tin, nickel and both hard and soft golds. 

Testing Required

In the planning stages of the design, testing requirements are considered. These aspects are discussed at length and most qualification tests can be performed during assembly. The types of testing that hermetic sealed connectors may have to undergo include:

  • Pressure testing
  • Leak testing
  • Geometrical testing
  • Electrical testing
  • Insulation resistance
  • Voltage

In addition to testing, quality seals are inspected thoroughly.

To design hermetic connectors, there are ranges of materials that may be used in the process. From glass to metal seals and advanced sealing techniques, there are options for a variety of connectors. When receiving custom connectors, it is crucial that you address all of your different requirements.

Vacuum Viewports

The Quick Guide to Vacuum Viewports

When you have a vacuum system, the viewport is an optical component that provides energy transmission in and out of the system. These are hermetically sealed and ensure high-functioning. Here is what you should now.

Vacuum Viewports Explained

You may choose vacuum viewports when you can reach the target in the chamber in a straight line. In other cases, you may be able to use a small number of mirrors to reach the target directly. A vacuum viewport may have two components. The flange and window both need to be designed utilizing the best materials possible. The windows, for instance, may be made from the following materials:

  • Sapphire
  • Fused Silica
  • Glass

The flanges, on the other hand may use:

  • Aluminum
  • Titanium
  • Kovar

Neither of these lists are exclusive. Viewports may be manufactured with a number of different materials.

Applications for Vacuum Viewports

A vacuum viewport is hermetically sealed, to ensure that any mechanical devices perform at the highest and most efficient capacity. When you choose a vacuum viewport, you can use the components in infrared, laser and optical applications. If you’re worried about the viewports fitting the needs of your machine, they can satisfy a wide variety of requirements.

In terms of vacuum systems, a vacuum viewport is necessary for high-functioning. Your materials and needs, of course, will be dependent on the type of system that you own. It’s important to keep that in mind when making your choice.

Glass-to-Metal vs Ceramic-to-Metal Seals: Hermetic Seal Products

We at Complete Hermetics are proud to offer a diverse array of different seals and feedthroughs that make us stand out as a top-tier hermetic seal products. The type of seal that will be best for your needs depends on which industrial application you will be using it for. In this short article, you will learn about the differences between glass-to-metal and ceramic-to-metal seals.

Ceramic-to-Metal Seals

Ceramic can withstand higher temperatures than glass, so ceramic-to-metal seals are best used in environments with very high voltages and operating temperatures. One thing to keep in mind if you go with the ceramic-to-metal option is that due to the increased amount of labor it takes to make one of these, your wait time may be longer after placing your order.

Glass-to-Metal Seals

Glass is a good option to go for if the environment involves electrical currents, due to its insulating qualities. It is also ideal for a high-pressure environment, even though its temperature threshold is lower than that of ceramic.

Finding the Right Seal

If you have decided which type of seal is best suited to your needs, you may be wondering which size to get. At Complete Hermetics, we can custom-make the perfectly shaped seal for whatever application you have in mind.

Call today at (714) 265-1238.