Effect of Coating on Instantaneous Interfacial Heat Transfer During Near-Rapid Solidification

For many rapid or near-rapid solidification processes, the interfacial heat transfer between the melt and the substrate is a key issue on the cooling and solidification rate of castings. For the purpose of controlling and adjusting of the interfacial thermal resistance, the effects of C/BN, Zn and organic coatings on the instantaneous interfacial heat flux and the solidified structure of AISI304 stainless steel solidification on copper substrate have been investigated by using an experimental simulator. The results show that C/BN coatings can improve the uniformity of heat flux and solidified structure; Zn coating can increase the heat flux and solidification rate in the growth stage of the solidified shell; organic coating will decrease the heat flux and the solidification rate and make re-melted structure on the surface of the solidified shell.