InSealing specializes in Ceramic-To-Metal Seals. And as we all know, ceramic-to-metal seals are widely used in Electrical insulation, high temperature, high pressure, high voltage, high-vacuum HV and ultra-high vacuum UHV reliability, cryogenics or corrosive environments. But Do you know the sealing types of ceramic and metal in vacuum system?
The ceramic-to-metal sealing parts have high temperature resistance, good air tightness and electrical insulation properties, so they are commonly used in various heating electrodes and leads in vacuum systems. Their sealing forms mainly have the following forms:
The first is the flat sealing. This sealing form is mainly used for sealing between the ceramic ring, the end face of the piece and the plane of the metal part. The bottom is divided into single-side sealing and clamping. The former has a large sealing force, poor thermal impact, low mechanical strength, requiring the linear expansion coefficient of ceramic and metal to be close to or thin-walled metal parts. The latter reduces the sealing force and can seal mismatched ceramic and metal parts.
The second is the sleeve sealing. This kind of sealing form is used for the sealing of metal cylinder and ceramic ring or sheet, which has high strength and good heat resistance after sealing, but it requires high processing accuracy of metal and porcelain parts. The specific is divided into: coat seal, porcelain parts pressure, high reliability, good heat shock resistance, high mechanical strength, can be sealed mismatched materials; The inner sleeve seal, the sealing force is large, in most cases, the ceramic is subjected to tensile stress, the heat shock and strength is not as good as the outer seal, it is appropriate to choose the linear expansion coefficient is smaller than the ceramic or close to the metal material seal.
The finally is the needle sealing. This kind of sealing form is to seal the solid metal needle in the ceramic hole, which is specifically divided into direct needle sealing and transition needle sealing. The direct pin seal is similar to the inner sleeve seal and is suitable for fine filaments. The diameter of the needle is not greater than 1mm, and the linear expansion coefficient is smaller than or close to the metal material sealing. The transition pin seal has strong reliability, and the metal pin with large mismatch with ceramic can also be sealed.
The above is a brief introduction to the form of ceramic metal sealing. If you want to know more, please feel free to contact us(InSealing).