Wettability of Ceramic Substrates by Silver Based Alloys

The temperature dependence of wettability (wetting angle, Θp(T)) for Ag-based melts on graphite and $Al_2O_3$ substrates is compared. Typical alloying effects are found, as the Ag host metal is gradually replaced by various metallic elements. The essence of alloying lies in the change of the electron/atom (e/a) ratio. This ratio is also manifested in the shift of wetting angles on the same substrate. The effect is also supported by the calculations based on the rigid band model, and is also in qualitative agreement with the Hume-Rothery rules. Nevertheless, the effects are partially smeared by other (metallurgical) factors, like the interaction between the oxygen-alloying elements and by the graphite substrate-oxygen interaction. In contrast, such effects are not pronounced in the case of $Al_2O_3$ substrates. As a consequence, Θp(T) exhibits an opposite trend in the case of two substrates. Crossovers of the Θp(T) curves were often found. The positions of crossovers depend on the chemical character and concentration of solute atoms. Segregation and epitaxial texture formation after solidification were also observed in certain alloy drops, especially in high concentration range. This phenomenon is not yet explained in every detail

The Comparison of Hardness and Coercivity Evolution in Various Fe-B Based Glasses (Including FINEMET Precursor) during Relaxation and Crystallization

Inverse relation exists between the hardness and coercivity change within the whole period of structural relaxation in the investigated Fe-B(Si) based metallic glasses. This relation is independent of B-content and composition. This inverse relation is no more valid in binary Fe-B glasses after the onset of crystallization, when both the hardness and coercivity exhibit rapid increase. In contrast, the inverse relation was in FINEMET type glasses between these properties preserved in the first step of crystallization during the whole period of nanocrystallization

The Comparison of Hardness and Coercivity Evolution in Various Fe-B Based Glasses (Including FINEMET Precursor) during Relaxation and Crystallization

Inverse relation exists between the hardness and coercivity change within the whole period of structural relaxation in the investigated Fe-B(Si) based metallic glasses. This relation is independent of B-content and composition. This inverse relation is no more valid in binary Fe-B glasses after the onset of crystallization, when both the hardness and coercivity exhibit rapid increase. In contrast, the inverse relation was in FINEMET type glasses between these properties preserved in the first step of crystallization during the whole period of nanocrystallization

Development of Crack Detection Method with 2 Dimensionally Generated 3 Dimensionally Reconstructed Images in THT Solder Joints

This work represents an interesting development in the detection and interpretation of crack evolution in through hole technology (THT) solder joints, which based on the development of general and common method. Serial sectioning is a useful method because it overcomes the problems associated with traditional two-dimensional metallographic techniques by providing information about (micro)structures in three-dimensions. In our work, serials sectioning with reconstruction method was utilized to visualize the 3D nature of cracks in through hole solder joint. Accurate quantitive analysis of the cracks, such as crack length, position and extension are presented with a help of the developed method: newly defined parameter and serial-cross sectioning method