| 摘要 |
In airtight envelopes such as those of luminous electric discharge devices in which ceramic material is sealed hermetically to glass, the ceramic material is free from silica and consists of a compound of an alkaline earth with the oxide of titanium or zirconium. The cracking of the glass due to the absorption of silica is thus avoided. Examples are, 1 or 2 parts of MgO or BeO with 1 part of TiO2 or ZrO2. The compounds when sintered at 1400 to 1500 DEG C. are non-porous to air and will join to metals. Other substances may be added to reduce the sintering temperature. The electric leads may pass through a plate formed of the ceramic material to replace the usual foot tube, and an enamel of soft glass can be used to seal the joint. The major part of the envelope may be formed of the ceramic material and the remainder of glass. Metals may be sprayed or sintered on the surface of the ceramic material. |
