AUTHOR=Li Chen , Fang Zhihong , Sun Boshan , Xiong Jijun , Xu Aodi , Guo Ximing , Hong Yingping 

TITLE=Process method of Si3N4 ceramic brazing sealed cavity for high-temperature application

JOURNAL=Frontiers in Chemistry

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.1019822

DOI=10.3389/fchem.2022.1019822

ISSN=2296-2646

ABSTRACT=<p>The process method of a Si<sub>3</sub>N<sub>4</sub> ceramic sealed cavity is realized by vacuum brazing and chemical reaction at 1,100°C and 0.5 MPa pressure. Through the combination of Si<sub>3</sub>N<sub>4</sub> ceramic polishing and thinning, inductively coupled plasma etching, and high-temperature metal filler (Ti-Zr-Cu-Ni) brazing process, a vacuum-sealed cavity suitable for high-temperature environments was prepared. The cross section of the bonding interface was characterized by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS), which indicated that the two Si<sub>3</sub>N<sub>4</sub> ceramic were well bonded, the cavity structure remained intact, and the bonding interface strength exceeded 5.13 MPa. Furthermore, it retained its strong bonding strength after in high-temperature environments of 1,000, 1,050, and 1,100°C for 1 h. This indicates that a brazed vacuum-sealed cavity can be used in high-temperature environments. Through the proposed method, pressure sensor that can withstand high temperatures can be developed.</p>