Crack-Healing Behavior and Mechanical Strength Recovery of 5 vol% Silicon Carbide Particle Dispersed Yttrium Monosilicate Composites

Abstract

Crack-healing effectiveness was investigated as functions of heat treatment time and temperature on 5 vol% SiC-dispersed Y 2 SiO 5 -based composites. Dense specimens of SiC/Y 2 SiO 5 composite were fabricated by the pulsed current sintering technique. Thermal oxidation for crackhealing was conducted at temperatures ranging from 1000 to 1300°C for from 1 to 24 h in air. Bending tests were carried out at room temperature on samples before and after heat treatment in order to clarify the crack-healing performance. The results show that SiC/Y 2 SiO 5 composites possess a considerable crack-healing ability. The surface cracks with approximately 200 µm in length introduced on the sample surface were disappeared completely after heat treatment at 1300°C for 1 h in air. Mechanism of crack-healing was considered as filling up of cracks by Y 2 Si 2 O 7 oxidation product which is formed by outward diffusion of cations. Bending strength of samples introduced surface cracks after heat treatment was recovered up to the level as high as that of as-sintered samples. [

Crack-healing performance and oxidation behavior of SiC dispersed yttrium silicate composites

“…The As the previous report [6], the outward diffusion of Y 3+ cations, which was responsible for the formation of Y 2 Si 2 O 7 layer on the sample surface, plays a major role in the crack-healing effectiveness of SiC/Y 2 SiO 5 composites. The formation of sub-micron spherical voids after high-temperature oxidation is the evidence of the outward diffusion of cations, as shown in Figure 7(a).…”

“…The authors have proposed SiC/Y 2 SiO 5 composites as the self-healing EBCs material applied for SiC f /SiC composites substrate [6]. Y 2 SiO 5 composites dispersed with 5 vol% SiC particles exhibited a good crackhealing ability induced by high-temperature oxidation process.…”

“…Furthermore, the self-healing composites were toughened by a non-oxide phase [6]. Crack-healing ability of the composites was induced by oxidation of the non-oxide dispersoid.…”

Self-healing ability and full strength recovery at medium temperatures of low content titanium carbide/alumina composites

“…2)-4) The well-known silicon carbide (SiC) healing agent, has also been employed to endow the self-healing ability for other ceramics like mullite, 5) zirconia, 6) and silicates. 7), 8) In most cases, the composites require a provision of relatively high temperatures (>1000 °C) in several hours so that an adequate amount of SiC transforms to glassy SiO 2 , which fills in and heals the cracks completely. These conditions seem ideal for high temperature applications, such as high-pressure gas turbine blades (working at 1100-1400 °C), but impractical for mid-range temperature applications like low-pressure turbine blades.…”

Effect of Initial Grain Size on Crack Healing Behavior under DC Electric Field of Zirconia (8Y‐CSZ) Ceramic

“…In order to remove the microcracks in the ceramic materials, self‐healing techniques have widely been studied in several material systems. [ 2–9 ] For the self‐healing techniques, although the microscale cracks can automatically be healed in situ by operating high temperatures, it is necessary to control the microstructures in advance; second phases should be dispersed in the matrix as a healing agent. Since the ceramic materials are highly sensitive to minor elements, dispersing the healing agent may influence the original mechanical/functional properties of the ceramic matrix.…”