Dense Layered Molybdenum Disilicide–Silicon Carbide Functionally Graded Composites Formed by Field‐Activated Synthesis

Abstract

Dense, layered, single-and graded-composition composites of MoSi 2 and SiC were formed from elemental powders in one step, using the field-activated pressure-assisted combustion method. Compositions ranging from 100% MoSi 2 to 100% SiC were synthesized, with relative densities ranging from 99% to 76%, respectively. X-ray diffractometry results indicated the formation of pure phases when the concentration of MoSi 2 was high and the appearance of a ternary phase, Mo 4.8 Si 3 C 0.6 , when the concentration of SiC was high. Electron microprobe analysis results showed the formation of stoichiometric and uniformly distributed phases. A layer-to-layer variation in composition of 10 mol% was sufficient to prevent thermal cracking during formation of the layered functionally graded materials.

In situ synthesis of SiCW/MoSi2 composite through SPS process

“…This process continued until the maximum operating temperature is reached, and the applied pressure densities the sample at the same time. Details of this method have been provided in previously published accounts [14,15]. MSC1 80 1200 100 5 MSC2 80 1300 100 5 MSC3 80 1400 100 5 MSC4 80 1500 100 5 MSC5 80 1600 100 5 MSC6 50 1500 100 5 MSC7 40 1500 100 5 MSC8 30 1500 100 5…”

“…Therefore, rapid heating is available and the total sintering time can be shortened. Even though there have been several work on MoSi 2 and MoSi 2 -based composites by the SPS method [14][15][16][17], no previous results on SPS MoSi 2 /SiC W composites via in situ processing have been reported.…”

Transport properties of functionally graded materials

“…1,2 Such materials have recently gained more attention owing to their unique transport properties that are suited to special applications, 1-3 for instance, as advanced heat-shielding materials in aerospace and electronics industries. [4][5][6] FGM has also been used in actuator devices where the materials behave better than the bimorph actuators in thermal resistance, peeling resistance, and reliability due to the absence of bonding agents. 7,8 Another electrical application of FGM is as a heat-electricity conversion material for design of energy conversion systems, likely raising the conversion efficiency by above 40% from a nuclear or solar source.…”

Combustion Synthesis: An Update

“…Such reactions were obtained in MoSi 2 B -Si composites in the FACS mode [32] . Functionally graded molybdenum disilicide -silicon carbide composites can also be formed by the same technique [33] . In this experiment, it was found that the formation of pure phases occurred when the concentration of MoSi 2 was high.…”