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Ceramic to Metal Seal

A ceramic to metal seal generally means a hermetic seal, a hermetic joint, or a hermetic bond. A few have no hermeticity requirement. Some has an intermediate sealing material (or sealant) in-between and some don’t have any.

IJ Research has extensive experience in the following five different types of ceramic to metal seals, joints and bonds. The terminologies used for each of the bonding techniques are described below:

1.Brazing metallized ceramic to metal using a braze (Thermo-metallurgical bonding)
2. Brazing non-metallized ceramic to metal using a specialty reactive based braze (Diffusion bonding driven thermo-metallurgical bonding)
3. Diffusion bonding ceramic and metal with nothing in-between. A liquid phase shall be in this category as well.
4. Glass sealing ceramic and metal (Fusion bonding using a sealing glass in-between)
5. Cofired bonding Ceramic and Metal that is a direct seal of ceramic and metal with no braze or glass in-between (Oxidation – sintering driven chemical bonding)

New terminologies in the listing above such as “thermo-metallurgical bonding”, “fusion bonding ceramic and metal” and “Oxidation – sintering driven chemical bonding” are the methodologies IJ Research created and we have been using and practicing over the course of many years. We strongly feel that we are unique in the processes, ability of choosing one technique over the five different techniques for customers’ specific need and solving (many of the) challenging issues that arise during development.

Fusion bonding can be done with a glass and metal combination or glass and metal oxide combination at high temperature. The metal shall go through a thermal reaction at the transition from a start of metal/glass to a final of metal oxide/glass. Diffusion bonding may require a few prerequisites to meet certain condition to enhance the adhesion. Thermo-metallurgical bonding is actually a chemical reaction through an oxidation of a metal and sintering together with all the metal oxides.

The commonly known process of ceramic to metal sealing requires firstly a metallization layer applied on the ceramic and then secondarily brazing the metallized ceramic and

the metal component together using a braze (or some cases solder). This two-step process may sound indirect as the processes listed above do not require the additional ceramic metallization step; however every application needs to review for the overall pros and cons of each process in terms of overall quality, certain assembly configurations and layouts. Braze can be replaced with a solder for certain low temperature applications. IJ Research has even developed an innovative flux-less soldering process such that there will be no entrapped flux interference in the sealing. Every technique has its own strength and weaknesses in a variety of applications and IJ Research has the experience and knowledge to guide customers to the best available option specifically to their project needs.

Metallization:

IJ Research has basically the following four different processes of metallization mostly for ceramics and some possibly for glasses.

1.UHT Metallization: Primarily for sapphire, translucent alumina and 99.5 % and up Al2O3
2. HT Metallization: Primarily for Al2O3 96% and up, sapphire and few other oxides.This can be used for BeO.
3. MT Metallization: Primarily for carbon products including diamond and graphite, nitride, carbides, BeO and zirconia
4. LT Metallization: For all glasses and ceramics including all above and others such as exotic crystals including sulfide and sulfate, Ge, etc.

Note: The terminologies of UHT, HT MT and LT are unique from IJ Research and we are purposefully using them as an effort to distinguish the multiple technologies or specific uses. Please refer to additional Corporate Literature called Metallization for further details.

Please contact IJ Research using 1-714-546-8522 or [email protected].