International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Obtaining gas-tight joints between mullite articles was made by crystallization of yttrium alumosilicate glass. The glass joint layer softens at joining temperature (1450-1470^oC) 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.

A new approach to design of oxide ceramic-ceramic nanocomposites instead of industrial technical ceramics has been proposed. The use of mixing of liquid solutions of reagents instead of powders mixing allows entering in the matrix material the oxide dopants in supersaturated concentrations. The synthesized nanoparticles contain a potential for the formation of various structures. By the controlling of heating regimes during nanopowders sintering processes we can control the diffusion processes on the particles volume and boundaries. The decomposition of initial supersaturated solid solution during heat treatment (especially at fast sintering) can lead to formation of multilevel nanocomposite structure in the ceramic matrix with enhancing mechanical, electrical, optical and magnetic properties. It is established on the example of zirconia that even a slight amount of aluminum oxide, nickel oxide, zinc oxide leads to a significant change of the nanopowders and ceramics properties.