METHOD OF APPLYING SURFACE HYDROPHILIC TREATMENT TO HEAT-TRANSFER TUBE

摘要

A method of applying a surface hydrophilic treatment to a heat-transfer tube with a good productivity, which obtains an excellent surface hydrophilic property not deteriorated for a long term. The method includes the steps of: heating a copper or copper alloy heat-transfer tube for 5 to 10 min at a temperature ranging from 250 DEG to 350 DEG C. in an atmosphere mainly containing an inert gas; and applying corona discharge or plasma discharge to the copper or copper alloy heat-transfer tube. To prevent the coloring, the atmosphere preferably contains O2 in a concentration of 3% or less and CO in a concentration of 1 to 5%, the balance being an inert gas.