A crack in a long standing ceramic problem
Ceramics are renowned for their excellent resistances to the extreme environments including high temperature and chemical corrosion, but their poor resistance to thermal shock that often occurs in the engines with ceramic components and in routine daily activities such as cooling a boiling egg in iced water has been a long standing problem in the thermal engineering. In this paper, we propose a novel method to make ceramics insensitive to thermal shock up to their melting temperature. In this method the surface of ceramics was biomimetically roughened into nano-finned surface that creates a thin air layer enveloping the surface of the ceramics during quenching. This air layer drastically increases the heat transfer resistance by about 10,000 times so that the strong thermal gradient and stresses produced by the steep temperature difference in thermal shock did not occur both on the actual surface and in the interior of the ceramics. This method effectively extends the applica
tions of existing ceramics in the extreme thermal environments.
