A ZrB2-based ceramic, containing short Hi-Nicalon SiC fibers, was fabricated with a Mo-impermeable buffer layer sandwiched between bulk and the outermost oxidation resistant ZrB2–MoSi2 layer, in order to prevent inward Mo diffusion associated fiber degradation reactions. This additional consisted of ZrB2 doped either Si3N4 or polymer-derived ceramics (PDCs) SiCN SiHfBCN. Scanning electron micro...

The ZrB2–MoSi2–AlN, ZrB2–SiC–AlN, and (Ti, Cr)B2–AlN ceramic composites were wetted with a nickel-based alloy in the Ni–Cr–W–Mo system. was found to wet well form contact angles θ = 0–12° for 3–7 min on their surface. wetting process less influenced by composition of main phase (ZrB2 Cr)B2) greater content SiC AlN dielectric additions, impairing composites. interaction areas studied cross-secti...

The tensile test in transition metal disilicides with C11b structure is simulated by ab initio electronic structure calculations using full potential linearized augmented plane wave method (FLAPW). Full relaxation of both external and internal parameters is performed. The theoretical tensile strength of MoSi2 and WSi2 for [001] loading is determined and compared with those of other materials. C...

Advanced engineered matrix composites (EMCs) require that the coefficient of thermal expansion (CTE) of the engineered matrix (EM) matches those of the fiber reinforcements as closely as possible in order to reduce thermal compatibility strains during heating and cooling of the composites. The present paper proposes a general concept for designing suitable matrices for long fiber reinforced com...

The need for structural materials with high-temperature strength and oxidation resistance coupled with adequate lower-temperature toughness for potential use at temperatures above ,1000 8C has remained a persistent challenge in materials science. In this work, one promising class of intermetallic alloys is examined, namely, boron-containing molybdenum silicides, with compositions in the range M...

A new high-temperature method for the deposition of gas-tight silicon carbide protective coatings with low gas permeability has been developed. The free carbon atoms form during pyrolysis hydrocarbon molecules. In turn, reacts molten contained in subsurface substrate layers and/or vapor. source vapor serves heated zone a reactor furnace. Such effectively protect SiC-C-Si and SiC-C-MoSi2 ceramic...