Silicon carbide nanocomposites reinforced with disordered graphitic carbon formed in situ through oxidation of Ti3C2 MXene during sintering

Abstract

This article describes the manufacturing of silicon carbide composites with the addition of quasi-two-dimensional titanium carbide Ti3C2, known as MXene. The composites were obtained by the powder metallurgy technique, consolidated with the use of the Spark Plasma Sintering method at 1900 °C and dwelled for 30 min. The influence of the Ti3C2 MXene addition on the microstructure and mechanical properties of the composites was investigated. The structure of the MXene phase after the sintering process was also analyzed. The results showed a significant increase (almost 50%) of fracture toughness for composites with the addition of 0.2 wt% Ti3C2 MXene. In turn, the highest hardness, 23.2 GPa, was noted for the composite with the addition of the 1.5 wt% Ti3C2 MXene phase. This was an increase of over 10% in comparison to the reference sample. The analysis of chemical composition and observations using a transmission electron microscope showed that the Ti3C2 MXene phase oxidizes during sintering, resulting in the formation of crystalline, highly defected, disordered graphite structures. The presence of these structures in the microstructure, similarly to graphene, significantly affects the hardness and fracture toughness of silicon carbide.

Influence of Ti3C2Tx MXene and Surface-Modified Ti3C2Tx MXene Addition on Microstructure and Mechanical Properties of Silicon Carbide Composites Sintered via Spark Plasma Sintering Method

“…The presence of carbon structures in the final microstructure was also confirmed in our previous publication [34]. According to the proposed mechanism, during the process of sintering, the spaces between grains located in close vicinity to MXene phases are enriched in oxidizing factors due to the release of physically absorbed water, oxygen, and functional groups (-OH, -O) from the surface.…”

“…They established that the presence of a metallic coating may notably change the form of degradation in the MXene phases. In our previous publication [34] on obtaining SiC-2D-Ti 3 C 2 MXene, we analyzed the structure of graphite flakes observed in the final microstructure of the obtained composites. The studies have shown that the MXene phases oxidize during sintering with the creation of highly defected carbon structures playing the role of reinforcement.…”

Investigation of MXenes Oxidation Process during SPS Method Annealing

“…The presence of porous particles, with a shape similar to MXene, proves the formation of the disordered carbon structures described in our previous papers [16]. However, the morphology of these particles differs from those we observed in the SiC matrix sinters [16,17]. Because the observations of the MXene powders after the annealing process did not show the presence of disordered carbon structures, similar tests were carried out for the SiC-C-B-Ti3C2 powder mixtures.…”

“…EDS (Energy-Dispersive Spectroscopy) analysis of these particles showed the presence of only carbon, which indicates a change in the degradation scheme of MXene in the presence of SiC-C-B. The presence of porous particles, with a shape similar to MXene, proves the formation of the disordered carbon structures described in our previous papers [16]. However, the morphology of these particles differs from those we observed in the SiC matrix sinters [16,17].…”

“…A different approach to the thermal stability problem of MXene was presented by Petrus et al [16]. They sintered SiC composites reinforced with MXene using the SPS (Spark Plasma Sintering) method.…”