Shape, size and surface roughness of glass sealing parts

    The size and distribution of stress in the sealing part are affected by the shape and size of the sealing part. When the stress exceeds the strength limit of the sealing material, it is bound to damage the sealed product. Generally speaking, after sealing, if the sealing part is only used as an integral part of the electron tube or electric vacuum device, it needs to be processed continuously, or it is used for sealing with the sealing part of the same electron tube or electronic device. Once again heat-treated or subjected to mechanical force. The temporary stress caused by the external force will be compounded with the thermal contraction stress between the materials. At the same time, the electronic tube or electronic device will also form a temporary stress during the use process, and compound with the original stress. As a result of the superposition of these temporary stresses, it will often lead to the destruction of the sealed product. It can be seen that when designing the sealing member, especially when considering the sealing method and design operation plan, the influence of the shape and size of the sealing member on the stress must be first paid attention to.

    The permanent stress formed at the same time as the difference in thermal shrinkage between materials and the temporary stress formed by various reasons are combined, and its value is quite considerable. If the influence of shape and size on stress is ignored, the stability of the sealing part may be affected. For example, in production practice, in order to reduce this stress, the plasticity of the thin metal edge can be used for sealing, and even the elasticity of metal can be used for sealing.

    Practice has shown that the metal surface is strongly corroded and treated in wet hydrogen. As a result, the roughness of the metal surface is increased and the metal components are selectively oxidized. In this way, the adhesion of glass on the rough metal surface is better than that of smooth metal coating. Stronger when glass. In the adhesion test, it was also found that if the base material has uniform unevenness, the adhesion is good, which will inevitably have a beneficial effect on the sealing.

(Huiputech)