Purpose: This study aims to solder AlN ceramics with a Cu substrate using an active type Sn-Ag-Ti solder. Soldering was performed with power ultrasound. The Sn3.5Ag2Ti alloy was first studied. Design/methodology/approach: It was found to contain a Sn matrix, where both Ag phase – ɛ-Ag₃Sn – and Ti phases ɛ-Ti₆Sn₅ and Ti₂Sn₃ – were identified. Ti contained in these phases is distributed to the interface with ceramic material. A reaction layer was thus formed. This layer varies in thickness from 0.5 to 3.5 µm and ensures the wettability of an active solder on the surfaces of ceramic materials. Findings: X-ray diffraction analysis proved the presence of new NTi and AlTi₂ phases on the fractured surface. Sn plays the main role in bond formation when soldering the Cu substrate with Sn-Ag-Ti solder. The Cu₃Sn and Cu₆Sn₅ phases, which grow in direction from the phase interface to solder matrix, were found in all cases within the solder/Cu substrate interface. The combination of AlN ceramics/Cu joint maintained a shear strength of 29.5 MPa, whereas the Cu/Cu joint showed a somewhat higher shear strength of 39.5 MPa. Originality/value: The present study was oriented towards soldering of AlN ceramics with a Cu substrate by the aid of ultrasound, and the fluxless soldering method was applied. Soldering alloy type Sn-Ag-Ti was analysed, and the interactions between the solder and ceramic and/or Cu substrate were studied. The shear strength of fabricated soldered joints was measured.

The work deals with the study of interaction Cu substrate (purity 5N) and Zn4Al and Zn6Al6Ag (purity 4N) solders for higher application temperatures. Soldering was performed with power ultrasound in the air without flux application at temperature 420°C. Acting time of ultrasonic vibration was 5 s. Soldered joints were assessed by optical light microscopy, EDX microanalysis and DSC analysis. It was found out that the melting temperatures of solders were 404.9°C and 396.9°C. Intermetallic layers (IM) CuZn4 and Cu5Zn8 were formed at the Cu/Zn4Al boundary. At the boundary Cu/Zn6Al6Ag there were formed AgZn3 and Cu5Zn8 IM layers. Shear strength of joint Cu/Zn4Al was 34.5MPa and shear strength of Cu/Zn6Al6Ag was 39MPa

This research aims to develop the direct soldering of aluminum nitride (AlN) ceramics with a copper substrate using Zn–Al–Mg solder. The solder type, Zn5Al3Mg, has a close-to eutectic composition with a melting point of 359 °C. The microstructure of Zn–Al–Mg solder is composed of solid solution (Al), solid solution (Zn), an Mg₂Zn₁₁ phase and a minority MgZn₂ phase. The tensile strength is from 82 to 169 MPa and depends on the magnesium content. The bond with AlN ceramics is formed due to the interaction of active Zn, Al and Mg metals with the substrate surface without forming a new transition phase. Zn and Al elements exert a substantial effect on bond formation with the Cu substrate. Magnesium does not contribute to bond formation with the Cu substrate. Two new phases, CuZn₄-ε and Cu₃₃Al₁₇/Cu₉Al₄/Cu₅Zn₈- γ, were observed, and form the transition zone of the joint. The maximum shear strength of the AlN/Cu joint fabricated using Zn5Al3Mg solder is 47 MPa. The maximum shear strength of the Cu/Cu joint fabricated using the same solder is 93 MPa.

The aim of the research was to characterize the soldering alloy In–Ag–Ti type, and to study the direct soldering of SiC ceramics and copper. The In10Ag4Ti solder has a broad melting interval, which mainly depends on its silver content. The liquid point of the solder is 256.5 °C. The solder microstructure is composed of a matrix with solid solution (In), in which the phases of titanium (Ti₃In₄) and silver (AgIn₂) are mainly segregated. The tensile strength of the solder is approximately 13 MPa. The strength of the solder increased with the addition of Ag and Ti. The solder bonds with SiC ceramics, owing to the interaction between active In metal and silicon infiltrated in the ceramics. XRD analysis has proven the interaction of titanium with ceramic material during the formation of the new minority phases of titanium silicide—SiTi and titanium carbide—C₅Ti₈. In and Ag also affect bond formation with the copper substrate. Two new phases were also observed in the bond interphase—(CuAg)₆In₅ and (AgCu)In₂. The average shear strength of a combined joint of SiC–Cu, fabricated with In10Ag4Ti solder, was 14.5 MPa. The In–Ag–Ti solder type studied possesses excellent solderability with several metallic and ceramic materials.

The aim of this research was to characterize soldering alloys of the type Sn–Sb–Ti and to study the ultrasonic soldering of SiC ceramics with a metal–ceramic composite of the type Cu–SiC. The Sn5Sb3Ti solder exerts a thermal transformation of a peritectic character with an approximate melting point of 234 °C and a narrow melting interval. The solder microstructure consists of a tin matrix, where the acicular constituents of the Ti₆(Sb,Sn)₅ phase and the sharp-edged constituents of the TiSbSn phase are precipitated. The tensile strength of the soldering alloy depends on the Ti content and reaches values from 34 to 51 MPa. The average strength of the solder increases with increasing Ti content. The bond with SiC ceramics is formed owing to the interaction of titanium, activated by ultrasound, with SiC ceramics, forming the (Ti,Si)₆(Sb,Sn)₅ reaction product. The bond with the metal–ceramic composite Cu–SiC is formed owing to the solubility of Cu in a tin solder forming two phases: the wettable η-Cu₆Sn₅ phase, formed in contact with the solder, and the non-wettable ε-Cu₃Sn phase, formed in contact with the copper composite. The average shear strength of the combined joint of SiC/Cu–SiC fabricated using the Sn5Sb3Ti solder was 42.5 MPa. The Sn–Sb–Ti solder is a direct competitor of the S-Bond active solder. The production of solders is cheaper, and the presence of antimony increases their strength. In addition, the application temperature range is wider.