The Technology Study Of Manufacturing Porous Coating By Flame-spraying Iron-based Composite Powder

The porosity of the traditional flame-sprayed porous surface coating is very small. In order to improve the porosity, this paper optimized the parameters of the flame spraying process and developed the technology of manufacturing the metallic porous surface coating by spraying directly iron-based composite powder without pore-forming materials. Moreover, this paper experimentally studied the impacts of process parameters on porous surface coating, such as the content of alloy powder, flame temperature and spraying distance, consequently further improved the flame spraying process of manufacturing the metallic porous surface coating. Besides, this paper tested the porosity, equivalent pore size and bonding strength of the porous surface coatings. Using water and alcohol as working fluid, this paper did experimental comparative study of the boiling heat transfer enhancement performances of the flame-sprayed porous surface coatings with different characteristic parameters. The results show that to the developed flame-sprayed porous surface coating, the average porosity is up to 64.5%, the boiling heat transfer coefficient is 3 - 14 times as large as that of the smooth surface, and the bonding strength could meet industrial application requirements. The relevant study results which have been obtained in this paper are instructive for the development and application of the heat transfer component with flame-sprayed porous surface coating.