Unrevealing the wetting behavior and mechanism of AgCuTi filler on negative thermal expansion Sc2W3O12 materials: Experiments and First-principles calculations

Abstract

Improving understanding of wetting behavior and mechanism between negative thermal expansion materials and filler metals was critical for the application of negative thermal expansion materials in the aerospace, precise instrument, etc. However, there is a lack of research on the wettability of negative thermal expansion materials. In this work, we employed experimental studies and First-principles calculations to investigate the wetting behavior, interfacial microstructure, and interfacial bonding characteristic between AgCuTi filler and Sc2W3O12 materials. The sessile drop method experiment investigated the influence of Ti content on the wettability of AgCuTi filler. When the Ti content was 4.6 wt%, the minimum contact angle of 15° was achieved. The XRD and TEM results indicated that active Ti reacted with Sc2W3O12 to form Cu3Ti3O, Ti3O5, and Cu0.4W0.6 compound. Furthermore, we investigated the interfacial bonding characteristics of Sc2W3O12 (010)/Ti (001) interface and Ti3O5 (001)/Ti (001) interface by First-principles calculations. According to the calculations results, the work of adhesion of Ti3O5/Ti interface system was higher than that of Sc2W3O12/Ti interface system, which suggested that the formed Ti3O5 reaction layer was conducive to improve the wettability of AgCuTi filler on the Sc2W3O12 materials. This work provided a new vision for the wetting mechanism between metal filler and negative thermal expansion materials, and was expected to provide guidance for the design of new material systems.