Crystallization kinetic of Li2O-MgO-Al2O3-SiO2 glass-ceramic and its application for joining of porous Si3N4 ceramic

A novel glass-ceramic of Li2O-MgO-Al2O3-SiO2 was developed to join porous Si3N4 ceramic itself for the first time. The crystallization kinetic and the microstructure evolution of the glass-ceramic were investigated. The crystallization activation energy E and Avrami exponent n illustrated that the glass-ceramic showed a high crystallinity and surface crystallization behaviour. The beta- and gamma- LiAlSi2O6 phases coexisted in the glass-ceramic and two minor phases of Mg2SiO4 and MgAl2O4 also precipitated. The porous Si3N4 was joined to itself successfully by using this glass-ceramic. A net-like LiAlSi2O6/MgAl2O4 glass-ceramic interlayer and an infiltration layer of glass/Si3N4 were formed in the joint. According to shear testing, the joint was reliable at room temperature and high temperature (850 degrees C). It demonstrates the feasibility of joining porous non-oxide ceramics by using glass-ceramic interlayers.

Automated summary

A novel glass-ceramic of Li2O-MgO-Al2O3-SiO2 was developed to join porous Si3N4 ceramic, demonstrating the feasibility of using glass-ceramic interlayers for joining porous non-oxide ceramics. The joint showed reliable performance at both room temperature and high temperature, forming a net-like glass-ceramic interlayer and infiltration layer.