Interfacial Phenomena between Liquid Si-rich Si-Zr Alloys and Glassy Carbon

Abstract

To succeed in the design and optimization of liquid-assisted processes such as reactive infiltration for the fabrication of tailored refractory SiC/ZrSi 2 composites, the interfacial phenomena that occur when Si-rich Si-Zr alloys are in contact with glassy carbon (GC) were investigated for the first time by the sessile drop method at T = 1450 • C. Specifically, two different Si-rich Si-Zr alloys were selected, and the obtained results in terms of wettability, spreading kinetics, reactivity, and developed interface microstructures were compared with experimental observations that were previously obtained for the liquid Si-rich, Si-Zr, near-eutectic composition (i.e., Si-10 at.%Zr) that was processed under the same operating conditions. The increase of the Si content only weakly affected the overall phenomena that were observed at the interface. From the practical point of view, this means that even Si-Zr alloys with a higher Si content, with respect to the near eutectic alloy, may be potentially used as infiltrant materials.

Interface Design in Lightweight SiC/TiSi2 Composites Fabricated by Reactive Infiltration Process: Interaction Phenomena between Liquid Si-Rich Si-Ti Alloys and Glassy Carbon

“…After 15 min, the contact angle values shown at the Si-Ti alloy/GC triple lines at T = 1450 • C are comparable and in agreement with other similar Si-rich systems previously investigated [24][25][26]30,36,37,[43][44][45][46][47]. On the other hand, a general trend of decreasing in the final contact angle measured after 15 min with the increasing of Si content is noticed.…”

“…Figure 2c shows the triple lines of the three Si-rich Si-Ti alloys/GC samples after the wetting experiments. The "halo" surrounding the drop perimeters, markedly visible for the Si-richer systems, is attributed to the presence of a thin SiC layer, as detected by SEM-EDS analysis, similar to other Si-rich-based alloys processed under the same operating conditions [36,37,[43][44][45][46][47], as shown in Figure 4. As it can be seen, the achievement of the steady-state conditions seems to be influenced by the different Si content (Figure 2a,b).…”