Synthesis of High-Temperature Silicides Via Rapid Solid-State Metathesis

Abstract

Mosi2 has a very favorable combination of materials properties, including a high melting point (2020°C), high strength at elevated temperatures, and resistance to high temperature oxidation and corrosion. These properties make it a good candidate for a hightemperature structural material; however, it has very poor ductility. A great deal of research has focused on improving the ductility of this alloy through various preparative routes. We have synthesized Mosi2, as well as WSi2, TaSi2, and NbSi2, using rapid solid-state metathesis reactions between a high oxidation state metal halide and an alkaline earth silicide. These reactions take advantage of the large exothermic heat of formation of the alkaline earth halide and can reach temperatures as high as the melting point of the product silicides. In addition, this approach yields crystalline products in seconds. The synthetic technique will be discussed along with characterization results.

Synthesis of Refractory Ceramics via Rapid Metathesis Reactions between Solid-State Precursors

“…By a careful choice of precursors, it is possible to synthesize well-mixed solid solutions and, occasionally, metastable phases. Over the past five years our group has reported on rapid SSM reactions that form crystalline NiS 2 , MoS 2 , GaAs and other III−V (13−15) semiconductors, in addition to successful syntheses of transition-metal phosphides, oxides, and other metal alloys (e.g., aluminides and silicides). 44b, Reactions forming mixed-metal solid solutions (e.g., Mo x W 1 - x S 2 ), as well as metal mixed-anion solid solutions (e.g., MoS x Se 2 - x and GdP x As 1 - x ) have been achieved. Recent results on refractory metal nitride, boron nitride, and metal boride systems are detailed below.…”

Size controlled mechanochemical synthesis of ZrSi2

“…Traditional routes to producing zirconium disilicide include silicothermic reduction, 12 electrochemical, 13 mechanochemical, 14 sintering, 15 arc-melting, 15 and self-propagating metathesis reactions. 16,17 However, these reactions are difficult to scale, do not yield pure ZrSi 2 , and do not allow for control of crystallite size. In addition, some routes require temperatures above 1000 1C.…”

Perspective on Micro-Supercapacitors

“…In addition, the transition metal silicides possess excellent interface properties with silicon and obtain low internal resistance because they are binder-free electrode materials (Ramly et al, 2018). It is worth noting that in addition to the above advantages, transition metal silicides also show intentional electrochemical properties, such as high theoretical energy FIGURE 5 | A brief timeline of the developments of promising of MSCs (In et al, 2008;Balcı et al, 2021;Yang et al, 2021a).…”

“…It is worth noting that in addition to the above advantages, transition metal silicides also show intentional electrochemical properties, such as high theoretical energy capacity and low discharge potential. Up to now, Transition metal silicides are prepared by various methods such as arc melting, self-propagating high temperature synthesis, mechanical alloying (MA) ( Okadome et al, 1995 ; Al-Joubori and Suryanarayana, 2016 ; Shin et al, 2017 ), Solid-state metathesis ( Jacubinas and Kaner, 1993 ; Nartowski and Parkin, 2002 ), Molten salt reaction technology ( Ma et al, 2004 ; Yang et al, 2004 ; Liu et al, 2013 ; Estruga et al, 2014 ), Microwave assisted synthesis ( Vaidhyanathan and Rao, 1997 ; Zhang et al, 2014 ; Zhang et al, 2018 ), Chemical vapour deposition (CVD) ( Seo et al, 2007 ; In et al, 2008 ; Higgins et al, 2010 ; Liu et al, 2012 ) and Solution synthesis route ( Baudouin et al, 2012 ; Geaney et al, 2012 ; Galeandro-Diamant et al, 2019 ) ( Figure 6 ). Each method described above has its own advantages and disadvantages.…”