Solderability of conventional Sn-37Pb solder pastes and Pb-free alloys (Sn-43Bi and Sn-2Ag-5Bi-O.5Cu) were examined on micro soldering using a YAG laser. Experiments were performed in order to determine the range of soldering parameters of a laser power density and an irradiation time for obtaining an appropriate wettability based on a visual inspection by a Japanese Industrial Standard. And the laser soldering processes were monitored by measuring temperature change inside solder joint (solder and Cu pad) and on a surface of a chip component. Next joining strength of chip components for surface mounting soldered on printed circuit board (glass epoxy) was tested on application thickness of solder paste (0.2, 0.3, and 0.4 mm). In addition, joining strength characteristics at different power density and materials were examined around thermal shock test by the gas phase method. As a result, characteristics of Sn-Ag-Bi-Cu (Pb-free) solder paste are equivalent to that of Sn-Pb solder paste.
In the field of industrial production of acetic acid via methanol carbonylation, the higher yield and efficiency are still pursued by employing the low water reaction system. Rhodium complex catalyst bound to pyridine resin exhibited high carbonylation activity and excellent immobilization characteristics under low water conditions, while strong durability is required for industrial use. In this connection, robust pyridine resin is essential under elevated reaction conditions. The relationship between durability and crosslinkage, and pore structure of resin was studied, as a result, novel pyridine resin resistant to industrial use has developed. Decomposition rate was evaluated based on the amount of pyridine group leached out from the resin and attrition rate was measured by the amount of powder generated by collision of resin beads each others in stirring liquid. The constant activity of rhodium complex catalyst bound to the novel pyridine resin during more than 7000 h was demonstrated using a continuous flow reactor unit. In addition, using an integrated pilot plant, byproducts could be recycled by equilibrium control and process performance including yields associated with catalyst activity, selectivity and stability in long term was demonstrated.
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