Bonding mechanisms of SiO_(2) glass and 1060 Al by ultrasonic assisted active metal soldering process

In this work,the ultrasonic assisted active metal soldering of SiO_(2) glass and Al was successfully achieved using Sn-2Ti solder filler at a low soldering temperature of 250℃in ambient atmosphere.A nano-crystallineα-Al2O3 layer with the average thickness of 13.9 nm and a nano-crystalline R-TiO_(2) layer with the average thickness of 16.2 nm are formed at the interface of Al/Sn and SiO_(2)/Sn respectively because Al elements did not diffuse from Al alloy side to SiO_(2) side,which verified that a sono-oxidation reaction had occurred during the ultrasonic assisted active metal soldering process.The soldered butt joints exhibited an average tensile strength of 25.31 MPa.

Ultrasonic-based surface patterning and interfacial reaction of ZrO_(2)ceramics

We demonstrate a process to achieve selective surface metallization of ZrO_(2)ceramics using ultrasound technology in atmospheric environments at 350℃,which bestows good weldability of ZrO_(2)to achieve rapid and reliable connections with other metals as well as ceramic materials.The challenge is that brazing or diffusion welding processes to accomplish metallurgical connections for ZrO_(2) typically require holding at elevated temperatures for minutes to hours,while the selective ultrasonic metallization process requires only a few seconds of processing without the application of covering films or solder resists.In this study,the selected Sn-2Ti alloy could effectively wet and spread on ZrO_(2)substrate under ultrasonication,and continuous interphase layers were rapidly formed in situ between ZrO_(2)and Sn-2Ti.The bonding strength for the ZrO_(2)/Sn-2Ti interface was well established with the highest shear strength of 37.1 MPa,and the fracture location occurred at the filler metal.The interfacial reaction layer thickened remarkably with the prolongation of sonication,accompanied by the partial crystallization of amorphous TiO and the formation of irregularly striped Ti_(11.31)Sn_(3)O_(10)nanocrystals.

Joining of SiO2 ceramic and TC4 alloy by nanoparticles modified brazing filler metal

Nano-Al2O3 particles modified Ag Cu Ni filler was adopted to braze the SiO2 ceramic and TC4.The effects of filler size as well as the brazing temperature on the interfacial microstructure and mechanical property of the joints were investigated.Nanoscale filler reduced the phases dimension and promoted the homogeneous distribution of microstructure,obtaining a higher joint strength when compared to microscale filler.The increase of brazing temperature made the accelerating dissolution and diffusion of Ti,which promoted the increase of thickness of Ti4O7+TiSi2 layer adjacent to SiO2 ceramic and diffusion layer zone nearby TC4 alloy.The hypoeutectic structure was produced in the brazing seam due to the high Ti content.The maximum shear strength of^40 MPa was obtained at 950°C for 10 min.

Fabrication of Si_(3)N_(4)/Cu direct-bonded heterogeneous interface assisted by laser irradiation

Joining of ceramic and metal is a key component in microelectronic device manufacturing,in which the integrity of bonded interface is critical in the performance and stability of the devices.Current methods with a problem of thick transition layer at the interface impeded heat flow,which degraded device service life seriously.Herein,we propose a laser-assisted bonding approach to join ceramic to metal directly without any intermediate material.By focusing the laser on the surface of β-Si_(3)N_(4) ceramic,the Si microcrystalline layer with stacked α-Si_(3)N_(4) nanocrystals was prepared first.The face-centered cubic(fcc)Si and hexagonal close-packed(hcp)β-Si_(3)N_(4) substrate take the coherent orientation relations of[001]_(fcc)║[0001]_(hcp) and(220)_(fcc)║(10■0)_(hcp).Then,the defect-free Si_(3)N_(4)/Cu bonded interface obtained by the reaction of the formed Si and Cu at elevated temperature in the 805-900℃range for 30 min demonstrated a strong and stable joining of ceramic to metal.The introduction of the laser provides a novel approach to join ceramics to metals,and the ceramic/metal component is expected to be a new configuration for package substrate in high-power device applications.