Surface metallization of Si3N4 ceramics with highperformance silver thick paste containing Bi-B-Zn glass frit

Si3N4 is a promising material for heat dissipation substrate due to its excellent thermal conductivity and mechanical properties. However, its application is limited by the difficulties in surface metallization. In this work, surface metallization of Si3N4 ceramic substrate is realized by thick film method for the first time. Conductive silver paste containing Bi2O3-B2O3-ZnO glass frit as glass binder was prepared, and high-performance silver thick films were formed on Si3N4 ceramic surface. The mechanical and electrical properties of silver films were significantly promoted with increasing sintering temperature, and silver films with high shear strength of 23.35 MPa and low resistivity of 3.41 mu Omega center dot cm were obtained when sintered at 600 C-degrees. In the meanwhile, the silver films exist high reliability under thermal cycles. The bonding between the silver thick film and Si3N4 ceramic substrate was considerably enhanced as a result of interfacial reaction, forming Bi2Si2O5 phase at the interface during sintering process. The formation mechanism was discussed and it is of great significance for the interfacial design in future studies. The results suggest that thick film method is a promising technology for obtaining high-quality surface metallization for Si3N4 ceramic substrate.

Automated summary

This study demonstrates the successful surface metallization of Si3N4 ceramic substrate using the thick film method. High-performance silver thick films were formed on the Si3N4 surface, with significantly improved mechanical and electrical properties at higher sintering temperatures. The bonding between the thick film and the substrate was enhanced through interfacial reaction, resulting in the formation of the Bi2Si2O5 phase. This study has great significance for future research on interfacial design.