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The aim of this research was to study the interaction and solderability of Al2O3 ceramics and Ni-SiC composite by use of an active solder type Bi11Ag1.5Ti1Mg. The chemical composition of the solder is 86.5 wt% Bi, 11 wt% Ag, 1.5 wt% Ti, 1 wt% Mg. Soldering was performed by ultrasonic activation. This solder has a wide melting interval with the initial melting temperature of 263 °C, what corresponds to the eutectic reaction. The liquidus temperature of this solder was determined at 437 °C. The bond between the ceramic and the solder is formed by the interaction of the active metals Bi, Ag and Mg with the surface of the substrate Al2O3. The thickness of the Mg reaction layer at the interface was approximately 0.8 μm. The bond at the interface between Ni-SiC and solder was formed due to the interaction of the active metals Bi, Ag, Mg and Ti. Feasibility of Bi11Ag1.5Ti1Mg solder was assessed on the basis of analyses of joint boundaries and joint shear strength measurements. The average shear strength of Al 2O 3/Bi11Ag1.5Ti1Mg/Ni-SiC joint was 54 MPa. [ABSTRACT FROM AUTHOR]

The aim of this research was to study the microstructure in soldered joint of SiC ceramics with Cu in cases of flux-less soldering with ultrasound assistance. The soldering was performed by ultrasonic activation of newly developed Bi–Ag–Ti based solder alloy. This new solder alloy was developed for flux-less soldering processes and meets the requirements for the versatility of its use for soldering metal and ceramic materials.Suitability for the application of Bi–Ag–Ti solder was assessed on the basis of analyses of joint boundaries and measuring the shear strength of the joint. Light analysis proved the formation of joints without cracks, pores or other imperfections. The SiC/Bi–Ag–Ti boundary was formed on the basis of the reaction between Si and Ti. The bond in Cu/Bi–Ag–Ti boundary was formed due to formation of mechanical mixture of Bi + Cu. The average shear strength of the SiC/Cu joint reached 40 MPa. [ABSTRACT FROM AUTHOR]

The study aimed at direct flux-free soldering of metal-ceramics composite (MMC) with a copper substrate. Soldering was performed with type Zn10In1Mg Zn-solder. The soldered joints were fabricated using power ultrasound. The solder used consists of a zinc matrix, while the solid solution (In) and MgZn2 phase were segregated on the grain boundaries. The soldered MMC joint is formed due to dissolution of the aluminium matrix in zinc solder. A new composite, composed of matrix consisting mainly of solid solution (Al) is thus formed. Moreover, there is also a solid solution present (In) and Cu3.2Zn0.7Al4.2 phase. The bond with copper substrate is formed due to interaction of Zn and Al from the solder at formation of two transient phases, namely Cu3.2Zn0.7Al4.2 and an unstable phase of Al(Cu,Zn)2. The average shear strength of combined joints of MMC/Cu is 16.5 MPa. [ABSTRACT FROM AUTHOR]

The work deals with the investigation of thermal properties and wettability of lead-free solders for higher application temperatures. For the research, the experimental solders SnSb5, ZnAl4, ZnAl6Ag6 and BiAg11 were used. For investigation of wettability, Ag, Cu and Ni substrates was used. To measure the solders melting intervals and their thermal properties, the DSC analysis was realized. The measurement of wettability was carried out in a controlled atmosphere by trigonometric method. Zn based solders wets none of the examined substrates. SnSb5 solder wets only Cu substrate with wetting angle of 54°. Soldering alloy BiAg11 wets all substrates, wherein the best result (23°) was achieved on Ag substrate. Shear strength of BiAg11 and SnSb5 joints reached higher value then classic PbSn5 solder. [ABSTRACT FROM AUTHOR]