Improving self-healing ability and flexural strength of ytterbium silicate-based nanocomposites with silicon carbide nanoparticulates and whiskers

Abstract

In the emerging era of aircraft industry, silicon carbide (SiC) is regarded as an appropriate material for gas turbine engine blades. In order to protect this ceramic component against the oxidation and volatilization in hot steam environments, environmental barrier coating should be utilized. The composite of SiC/Yb 2 Si 2 O 7 Yb 2 SiO 5 with self-healing ability is a candidate for the top layer of this coating. In this study, the crack-healing behavior of SiC/Yb 2 Si 2 O 7 Yb 2 SiO 5 nanocomposites is investigated by pre-cracking followed by annealing in oxidizing environments. Comparing to previous studies, the healing time and healing temperature can be reduced to 15 min and 800°C by increasing the volume fraction of SiC to 20 %. In addition, nanocomposites with both selfhealing ability and superior strength were created in this research by combining two types of SiC filler (whiskers and nanoparticulates). The self-healing mechanism in these composites is the SiC oxidation and silicate transformation associated with their volume expansion, which is evidenced by X-ray diffraction and scanning electron microscope. According to the results, the best volume ratio between whisker and nanoparticulate is determined as 1/3.

Effect of SiC Content and Particle Size on the Self-Healing Property of Plasma-Sprayed Environmental Barrier Coatings

“…Regarding crack healing and new crack initiation, smaller SiC particles may have caused more rapid volume expansion owing to their larger specific areas. In a previous study, 21) it was reported that a Yb 2 Si 2 O 7 / SiC sintered body using two types of SiC shapes, SiC particles with a specific surface area of 17.16 m 2 /g and SiC whiskers with a specific surface area of 8.47 m 2 /g, showed better self-healing properties when SiC particles with a larger specific surface area were used. The current results of our study are considered valid, as similar results have been also reported 19) for the thermal spray coatings at an oxidation time of 100 h. Next, we focused on SiC content.…”

Self-Healing Nanocomposites—Advancements and Aerospace Applications

“…Consequently, self-healing nanocomposites have been used to produce fixed and mobile jet engine components [118,119]. In particular, for aerospace combustion chambers, selfhealing nanocomposites have been designed [120,121]. In addition to high temperature, pressure, and damage resistance, self-healing nanomaterials revealed corrosion resistance properties for engine components [122].…”

“…chambers, self-healing nanocomposites have been designed [120,121]. In addition to high temperature, pressure, and damage resistance, self-healing nanomaterials revealed corrosion resistance properties for engine components [122].…”

Advanced Self-Healing Ceramics with Controlled Degradation and Repair by Chemical Reaction

“…Recently, materials that utilize chemical reactions as a healing (repair) function have been developed and studied. Conventional self-healing ceramics utilize oxidation reactions of non-oxides as the healing function and can only be used at temperatures above 800 • C [1][2][3][4][5][6]. To further expand the range of applications, lowering the temperature at which healing occurs is investigated.…”