Enhanced thermal shock resistance of ultra-high temperature ceramic by biomimetic surface modification

Abstract

The manipulation of the heat flow in a ceramic matrix composite is of great importance in industrial and academic fields. Energy flow, as a typical behavior of heat motion in ceramic surfaces can be confined within specific sites during thermal shock experiments, which weakens the temperature gradient distribution, and hence suppresses the crack propagation. The heat flow can be rationally controlled by the introduction of a nanostructured surface with a diverse forced convection coefficient and heat transfer resistance. Taking inspiration from a nanofin surface, yttria-stabilized zirconia (YSZ) nanostructures were fabricated using the sol-gel method. This bio-inspired coating exhibits a high forced convection coefficient (2.884 times) and high heat transfer resistance (30 times) because of the existence of irregular nanowires arrays and a porous nanostructure. The introduction of the nanostructured coating resulted in the rapid depression of the thermal gradient and stress concentration, and the crack propagation was also effectively suppressed. This sol-gel coating method effectively enhanced the thermal shock resistance of the ceramic materials, and indicates the potential for the application of ceramics in extreme environments.

Study on the effect of sample shapes on the thermal shock behavior of ZrB2‐SiC‐Graphite sharp leading edge

“…The thermal expansion coefficients and thermal conductivities of ZrB 2 ‐SiC‐Graphite ceramic as a function of temperature, as shown in Figure 7, are imported before simulation. The simulation assumed an elastic modulus of 420 GPa, Poisson's ratio of 0.12, and a heat transfer coefficient of 10 000 W/(m 2 K) at the stagnation point . The set temperature ( T 0 ) was taken as 650°C, which was the critical failure temperature ( T c ) of D s SLEs, and the thermal shock time of 1.0 seconds, which was the crack initiation time of D s SLEs as reported in Ref.…”

Effect of high temperature on the mechanical properties of hierarchical porous cenosphere/geopolymer composite foams

“…Although the geopolymer shows optimization of pore structure for function concerns, the appropriate mechanical properties still need to be considered for practical application. Like ceramics, the addition of reinforcements is usually an effective approach to improve their mechanical performance 19 . Materials like graphene, 20 nanotubes 21 and fibers 22 are widely used to improve the ceramic matrix.…”

“…Like ceramics, the addition of reinforcements is usually an effective approach to improve their mechanical performance. 19 Materials like graphene, 20 nanotubes 21 and fibers 22 are widely used to improve the ceramic matrix. This facilitates researchers to explore proper reinforcements for geopolymer to produce a type of low cost geopolymer composite foam with good mechanical performance.…”