Silver paste is widely used in power electronics as a die-attach material owing to its low-temperature sinterability, high melting point, and excellent electrical and thermal conductivities in sintered joints. However, owing to the mismatch in the coefficient of thermal expansion (CTE) between the joints and chip, the high Young’s modulus of sintered silver hinders the mitigation of the high thermal stress generated during the operation of power modules, which increases the susceptibility of sintered joints to cracking, thereby leading to potential failure. This study developed a facile approach to synthesizing bayberry-like Ag microparticles (AgMPs) through the in situ assembly of silver nanorods, resulting in a uniform distribution of nanoscale structures and mesopores on the particle surface. These particles exhibited a high specific surface area of 2.5389 m 2 ·g −1 , which enhanced their sintering activity, enabling sintering to occur at 149.7 °C. Furthermore, the porous structure of the AgMPs effectively reduced the density of joints formed by sintering AgMP paste, thereby lowering the Young’s modulus of the joints. The small grain size and intricate internal substructure of the joints yielded high shear strength, which reached 112.50 MPa at 250 °C. The Young’s modulus could be adjusted, and the pores provided by the AgMPs maintained the Young’s modulus within a low range (15.11–29.61 GPa), effectively mitigating thermal stress. These new bayberry-like porous AgMPs offer a promising option for die-attach materials in electronic packaging. Graphical abstract
We present here a novel strategy for textile sample treatment, using galvanic displacement-based substrates, to identify anthraquinone dyes by surface enhanced Raman spectroscopy (SERS). This global procedure of SERS analysis, using several silver microparticles , in particularly those of dendritic shape, formed by reducing silver nitrate with zinc or copper, can be accomplished within 20 min. Compared to the synthesis of standard Lee-Meisel colloids, the preparation of silver dendrites provides a simple, fast and cost-effective route to produce reliable SERS substrates. The most fascinating feature is that the textile fibers analyzed are almost simultaneously covered with the substrates once the galvanic displacement reaction is triggered. This method was successfully applied to discriminating between alizarin and purpurin in a 6th-9th century samite with bird roundels, and carminic acid and laccaic acid in a 1740s chinoiserie brocade. However, as is the case with other silver substrates, the Raman signals of the insect dyes normally overlapped those of the plant dyes in the SERS profiles.
危险品化学品经营许可证（带存储）