Effect of Ti addition on the wetting and brazing of Sn0.3Ag0.7Cu filler on SiC ceramic

Abstract

The wetting behavior of Sn0.3Ag0.7Cu (SAC) filler with the addition of Ti on SiC ceramic was investigated using sessile drop method. SiC/SiC was brazed by SAC‐Ti filler with different Ti content at 1223 K (950°C) for 10 minutes. The wettability of SAC‐Ti filler on SiC was significantly enhanced with the addition of Ti. The contact angle decreased at first and then increased with increasing Ti content. The lowest contact angle of 9° was obtained with SAC‐1.5Ti (wt%) filler. When Ti content further increased to 2.0 wt%, the contact angle increased, due to the intense reaction of Ti–Sn. The reaction between Ti and SiC controlled the wetting behavior of SAC‐Ti on the SiC substrate and the reaction products such as TiC and Ti5Si3 were formed. The wetting of SAC‐Ti on SiC was reaction‐controlled. Interfacial reaction products TiC and Ti5Si3 were observed. The wetting activation energy in spreading stage was calculated to be 129.3 kJ/mol. Completely filled SiC/SiC joints were obtained using the filler with Ti content higher than 0.5 wt%. The fillet height increased firstly then decreased with mounting Ti content. The shear strength of joints increased first with the addition of Ti then decreased with Ti content increasing to 2.0 wt%. The highest shear strength of 35.7 MPa was obtained with SAC‐1.5 Ti (wt%) filler.

Joining of SiO2 glass and 316L stainless steel using Bi–Ag-based active solders

“…Thus, a part of the Ti is not available to enhance the bonding. Similar results have been reported by Li et al [60] concerning the reaction layer thickness during brazing of SiC using a Sn-Ag-Cu-Ti alloy. The authors observed a decrease in the reaction layer thickness with Ti contents [ 1.5 wt.%, which is attributed to the presence of Ti-Sn phases.…”

“…The authors observed a decrease in the reaction layer thickness with Ti contents [ 1.5 wt.%, which is attributed to the presence of Ti-Sn phases. An increase in solid fraction during soldering causes an increase in the apparent viscosity of the melt, which counteracts good wetting behaviour [60,61]. The lack of bonding for alloy A3 may be attributed to this effect.…”

Wetting behavior and brazing of titanium‐coated SiC ceramics using Sn0.3Ag0.7Cu filler

“…It should be noted that the micron thickness of continuous strip Ti-Sn compounds (Spot B) adjacent to Ti-Si-C reaction layer was formed via the direct brazing using SAC-Ti filler. According to our previous results, 33 Ti-Si-C layer constitute with Ti 5 Si 3 and TiC, and the Ti-Sn layer was mainly composed of Ti 6 Sn 5 . Figure 9 showed the room-temperature shear strength of SiC joints using different brazing methods at 900°C for 10 minutes.…”

“…As droplet spread outward, Ti element diffused to SiC substrate and accumulated on the interface of liquid droplet/SiC, then the reaction of Ti and SiC occurred, thus SiC could be wetted by Ti containing droplets with chemical reaction. TiC and Ti 5 Si 3 were formed at the interface due to the insufficient active Ti diffused from droplet . Besides, Ti–Sn compounds were formed with the reaction of Ti and containing Sn droplet, which consumed the active Ti element and reduced droplets fluidity .…”

“…TiC and Ti 5 Si 3 were formed at the interface due to the insufficient active Ti diffused from droplet. 33 Besides, Ti-Sn compounds were formed with the reaction of Ti and containing Sn droplet, which consumed the active Ti element and reduced droplets fluidity. 16 In coated SiC/SAC system, Ti-Sn compounds were reduced resulted from the lack of active Ti element in droplet and trace amounts of Ti element diffused to droplet due to concentration gradient at high temperatures.…”