Fast Quenching on Porous Structured CuO Surface
We studied fast quenching on porous micro-structured surface under atmospheric and saturated water condition. Cupric oxide (CuO) micro-particle porous-layer coating was fabricated by electro-chemical deposition (ECD) at a brass sphere with the diameter of 15mm. The base diameter, height and particle diameter of micro-structures fabricated by the ECD are 20µm, 100µm, and 1µm, respectively. For the comparison, we prepared additional case of surface condition of which chemical composition is identical with the CuO; nano-structured surface (NS) and micro-/nano-structured surface (MNS). Quenching on the ECD surface is considerably faster than other surface conditions, and, this is originated by the minimum film boiling temperature Tmin enhancement. Through visualization in quenching, we can observe explosive fluctuation of the liquid-vapor interface on the ECD surface immediately after the initiation of the quenching. Based on the fin analysis, we concluded that liquidsolid contact in the high temperature could be explained by local cool-down at the tip of micro-structures, and, this can contribute to Tmin enhancement during quenching.