OBTAINING OF GAS-TIGHT GLASS-CERAMIC JOINTS OF MULLITE ARTICLES THROUGH THE NANOCRYSTALLIZATION OF Y2O3-Al2O3-SiO2 GLASS
Obtaining gas-tight joints between mullite articles was made by crystallization of yttrium alumosilicate glass. The glass joint layer softens at joining temperature (1450-1470oC) to bond the mullite samples without additional pressure and then crystallized during cooling. The good adhesion of crystallized glass to mullite surfaces ensue the gas-tight joints with permittivity 2.5*10-4 sccm/cm. The eutectic like crystallization of initial yttrium aluminosilicate glass into yttrium silicate and mullite lead to formation the nanocomposite structure which ensure the 4 point bending strength value near 105 MPa.