Glass-ceramic cement for vacuum-tight joint

Abstract

Synthesis of fusible glass of ZnO – PbO – B[2]O[3] system at the maintenance of components, wt %: B[2]O[3] – 10–45; ZnO – 5–40; PbO – 50–85 is carried out. It was established that stability of a vitreous state is defined by a ratio of ZnO / (PbO + B [2]O[3]) in the glass composition. Dependences of thermal and rheological characteristics of glass systems of ZnO – PbO – B[2]O[3] from a chemical composition are studied. The increase in the maintenance of B[2]O[3] superseded by PbO causes the essential growth of viscosity and decreas e of its gradient. The components able to reduce viscosity are arranged in the following way: B[2]O[3]→ZnO →PbO. By the results of research of glass rheological properties of ZnO – PbO – B[2]O[3] system, the area of glass compositions with viscosity less than 10{5} Pa · s at a temperature not over 450°C that provides the demanded spreadability indicators is defined. Regulation of indicators of TCLE is reached by creation of compositions glass – a crystal filler. Influence of such crystal filler as zircon, spodumene, cordierite on properties of composite glass-ceramic cement is re searched. The target TCLE indexes being equal to (77 ± 1) · 10{–7} K{–1} are achieved by the introduction of a spodumene. The composite glass-ceramic cement, intended for vacuum-tight connections of fiber-optical elements with a metal frame was developed. TCLE indexes of the glass-ceramic cement are equal to 77.2 · 10{–7} K{–1}, that coordinates it with TCLE containing a fiber-optical element. Temperature of composite glass-ceramic cement soldering is 450 ± 5°C, temperature of its deformation – 520 ± 5°C.