Effect of chromium carbide on the elastic modulus of modified reaction-bonded silicon carbide
DOI: 10.62564/M4-MP1054
Mykyta Pinchuk1, Mykola Gadzyra1, Ihor Hnylytsia2
1Frantsevich Institute for Problems of Materials Science National Academy of Science of Ukraine 2Ivano-Frankivsk National Technical University of Oil and Gas, Ukraine
The study used industrial silicon carbide powders (3, 28, 80, 100)μm and synthesized nano-sized silicon carbide (0.07μm) in the form of its solid solution of carbon and chromium carbide with an average particle size of 0.2μm. Chromium carbide was synthesized in an induction furnace at 1550°C in an argon atmosphere[1]. Chromium oxide and thermo-expanded graphite (TEG) powders were used as synthesis components. X-ray diffraction was performed on an Ultima IV diffractometer in the Bragg-Brentano focusing geometry (CuKα - monochromatic radiation, graphite bent monochromator on the diffracted beam). The values of the first-order stresses were determined by the sin2(ϕ) method for cubic SiC. The measurements at ψ angles of 10, 20, 25 and 30 degrees were performed by the isoinclination method. Thus, the value of the first-order stresses perpendicular to the sample plane along the [311] crystallographic direction in cubic β-SiC was obtained. When 3 to 10% of highly dispersed Cr₃C₂ is introduced into the composition of the initial batch and infiltrated with liquid silicon in an argon atmosphere, a decrease in the modulus of elasticity is observed, followed by its increase in reaction-bonded silicon carbide (RBSC). The minimum on the curve corresponds to a modifier content of 5%, which corresponds to a modulus of elasticity of 260-280 GPa. This dependence was established on RBSC of different initial fractions of industrial silicon carbide, including synthesized nano-sized silicon carbide. X-ray structural studies have established that the modification process with chromium carbide leads to the occurrence of internal compressive stresses in contrast to the tensile stresses for unmodified RBSC. It is shown that the dependence of internal stresses on the modifier content correlates with the modulus of elasticity. The minimum value of the modulus corresponds to the maximum value of the internal compressive stresses.
Keywords
chromium carbide, ceramics, the tensile stresses
Acknowledgments Not provided
References
[1] Features of the synthesis of chromium carbide using different forms of carbon //Powder Metallurgy.– 2017.–№9,10.– P. 34-39
