In this study, the effect of electroless Pd-P plating on the bonding strength of the Bi-Te thermoelectric elements was investigated. The bonding strength was approximately doubled by electroless Pd-P plating. Brittle Sn-Te intermetallic compounds were formed on the bonding interface of the thermoelectric elements without electroless Pd-P plating, and the fracture of the bond originated from these intermetallic compounds. A Pd-Sn solder reaction layer with a thickness of approximately 20 µm was formed under the Pd-P plating layer in the case of the electroless Pd-P plating, and prevented the diffusion of Bi and Te. In addition, the fracture did not occur on the bonding interface but in the thermoelectric elements for the electroless Pd-P plating because the bonding strength of the Pd-Sn reaction layer was higher than the shear strength of the thermoelectric elements.
Ag and Cu powders were mechanically alloyed using high-energy planetary milling to evaluate the sinter-bonding characteristics of a die-attach paste containing particles of these two representative conductive metals mixed at atomic scale. This resulted in the formation of completely alloyed Ag-40Cu particles of 9.5 µm average size after 3 h. The alloyed particles exhibited antioxidation properties during heating to 225°C in air; the combination of high pressure and long bonding time at 225°C enhanced the shear strength of the chip bonded using the particles. Consequently, the chips sinter-bonded at 225°C and 10 MPa for 10 min exhibited a sufficient strength of 15.3 MPa. However, an increase in bonding temperature to 250°C was detrimental to the strength, due to excessive oxidation of the alloyed particles. The mechanically alloyed phase in the particle began to decompose into nanoscale Ag and Cu phases above a bonding temperature of 225°C during heating.
The paper presents the results of an extensive investigation of asphalt concrete specimens with geosynthetic interlayer. The subject of this research is evaluation of influence of geosynthetics interlayer applied to bituminous pavements on interlayer bonding of specimens. The results of the tests proves that when geosynthetic is used, the bonding of interlayer depends mainly on the type of bituminous mixture, the type of geosynthetic, and the type and amount of bitumen used for saturation and sticking of geosynthetic. The amount of bitumen used in order to saturate and fix the geosynthetic significantly changes the interlayer bonding of specimens.