Synthesis of Ag–Sb Alloy Nanoparticles and Their Application to Bonding Materials

Abstract

We investigated the synthesis of Ag–Sb alloy nanoparticles by using the mixture solution of alkyl carboxylic acid and alkyl amine. In our synthesis method, ternary alkyl amine or ascorbic acid was employed as a reduction agent. The tuning of size, morphology, Ag/Sb composition ratio, and crystalline structure of nanoparticles were conducted by varying the Ag/Sb composition ratio for preparation, surfactant concentration, synthesis temperature, and reduction agent. When ternary amine was used as a reduction agent, the precipitated phases were identified by XRD and ED to be the mixture of Ag (FCC) and the ζ–phase(HCP structure). An increase in the proportion of oleic acid led to the disappearance of the ζ–phase. When ascorbic acid was used as a reduction agent, Ag–Sb alloy nanoparticles with ζ–phase were obtained. It is presumed that the reduction of Sb involves both the reduction gas generated from the decomposition of organic compounds and a reduction in the activity of Sb due to alloying. Then, we evaluated the properties of Ag–Sb alloy nanoparticles as a bonding material. Metal nano-ink using these nanoparticles showed promising mechanical strength, with an average breaking shear strength reaching 43 MPa under conditions of 350°C and 15 MPa.