HEAT TRANSMISSION PART FOR HEAT EXCHANGER AND PRODUCTION

摘要

PURPOSE:To improve the boiling heat transfer rate of a heat exchanger by imposing a mixture composed of fie metallic particles and Mg-contg. Al brazing filler metal particles onto a base plate made of Al and heating the same up to the brazing temp. in a non-oxidizing atmosphere. CONSTITUTION:The mixture composed of the fine particles of the Al alloy and the particles of the Al brazing filler metal 2 contg. Mg is imposed on the Al base plate 3 constituting the heat transmission part of the heat exchanger and is heated to the temp. right above the melting point of the brazing filler metal 2 in the non-oxidizing atmosphere. The evaporation of Mg arises before and after melting of the metal 2 and therefore the surfaces of the particles of the alloy 1 and the base plate 3 are reduced and the oxide films are removed therefrom. The molten metal 2 wets the surface of the alloy 1 particles and the plate 3 by surface tension and solidifies on cooling. The porous layer of the alloy 1 is thus formed on the plate 3. The remarkable improvement of the boiling heat transfer rate of the heat exchanger is thus made possible.