The experimental study of the Bi-Sn, Bi-Zn and Bi-Sn-Zn systems

The binary BiSn was studied by means of SEM (Scanning Electron Microscopy)/EDS (Energy-Dispersive solid state Spectrometry), DTA (Differential Thermal Analysis)/DSC (Differential Scanning Calorimetry) and RT-XRD (Room Temperature X-Ray Diffraction) in order to clarify discrepancies concerning the Bi reported solubility in (Sn). It was found that (Sn) dissolves approximately 10 wt% of Bi at the eutectic temperature. The experimental effort for the BiZn system was limited to the investigation of the discrepancies concerning the solubility limit of Zn in (Bi) and the solubility of Bi in (Zn). Results indicate that the solubility of both elements in the respective solid solution is approximately 0.3 wt% at 200 C. Three different features were studied within the BiSnZn system. Although there are enough data to establish the liquid miscibility gap occurring in the phase diagram of binary BiZn, no data could be found for the ternary. Samples belonging to the isopleths with w(Bi) 10% and w(Sn) 5%, 13% and 19% were measured by DTA/DSC. The aim was to characterize the miscibility gap in the liquid phase. Samples belonging to the isopleths with w(Sn) 40%, 58%, 77/81% and w(Zn) 12% were also measured by DTA/DSC to complement the study of BiSnZn. Solubilities in the solid terminal solutions were determined by SEM/EDS. Samples were also analyzed by RT-XRD and HT-XRD (High Temperature X-Ray Diffraction) confirming the DTA/DSC results for solid state phase equilibria

High speed synchrotron X-ray imaging studies of the ultrasound shockwave and enhanced flow during metal solidification processes

The highly dynamic behaviour of ultrasonic bubble implosion in liquid metal, the multiphase liquid metal flow containing bubbles and particles, and the interaction between ultrasonic waves and semisolid phases during solidification of metal were studied in situ using the complementary ultrafast and high speed synchrotron X-ray imaging facilities housed respectively at the Advanced Photon Source, Argonne National Laboratory, US, and Diamond Light Source, UK. Real-time ultrafast X-ray imaging of 135,780 frames per second (fps) revealed that ultrasonic bubble implosion in a liquid Bi-8 wt. %Zn alloy can occur in a single wave period (30 kHz), and the effective region affected by the shockwave at implosion was 3.5 times the original bubble diameter. Furthermore, ultrasound bubbles in liquid metal move faster than the primary particles, and the velocity of bubbles is 70 ~ 100% higher than that of the primary particles present in the same locations close to the sonotrode. Ultrasound waves can very effectively create a strong swirling flow in a semisolid melt in less than one second. The energetic flow can detach solid particles from the liquid-solid interface and redistribute them back into the bulk liquid very effectively

The Ni-rich part of the Ni-P-Sn system : isothermal sections

Due to the use of phosphorus-containing nickel substrates in microelectronics, understanding of their reaction with Sn-based solders and knowledge of the corresponding reaction products is highly important. Therefore the ternary Ni-P-Sn system was investigated experimentally using x-ray diffraction (XRD), scanning electron microscopy (SEM) + energy dispersive x-ray spectroscopy (EDX)/wavelength-dispersive x-ray spectroscopy (WDS), and differential thermal analysis (DTA). Sample preparation was done by alloying powders of the starting components contained in alumina crucibles in evacuated quartz tubes. In this study the phase equilibria in the Ni-rich part of the ternary Ni-P-Sn system are described in the form of three partial isothermal sections at 550°C, 700°C, and 850°C. A total of five ternary compounds exist in the Ni-rich part, and the binary Ni3Sn2 HT phase was found to dissolve 17.6 at.% P at 850°C. This well agrees with literature reports, while a different extent and shape of the large homogeneity range of this phase were found. Between 850°C and 700°C phase equilibria change significantly due to the formation of the ternary phases Ni10P3Sn5 (T3), Ni13P3Sn8 (T4), and Ni2PSn (T5). © 2009 TMS

Thermodynamic properties and melting behavior of Bi-Sn-Zn alloys

The partial and integral enthalpies of mixing of liquid Bi-Sn-Zn alloys were determined at 500øC by a drop calorimetric technique using a Calvet-type microcalorimeter. The ternary interaction parameters in the Bi-Sn-Zn system were fitted using the Redlich-Kister-Muggianu model for substitutional solutions, and isoenthalpy curves of the integral molar enthalpy of mixing at 500øC were constructed. Furthermore, a DSC technique was used to determine the liquidus temperatures in three sections (3, 5, and 7 at.% Zn) as well as the invariant reaction temperature of the ternary eutectic L ⇄ (Bi) + (Sn) + (Zn). The ternary eutectic reaction was found at 135ø