COPPER ALLOY PIPE HAVING CORROSION PREVENTING COAT ON INNER SURFACE

摘要

PURPOSE: To prevent blistering of coat caused by reaction of molecules and ions in the coat by addition of silica of a predetermined amount and of a parti cle size in a predetermined range, which silica serves as an extender pigment in the coat to prevent passage of molecules and ions in the coat. ;CONSTITUTION: Extender pigments are generally granular to have a relatively large particle size in the order of 10 to 20μm, thus facilitating passage of molecules and ions through between particles. So, fine particles are filled in voids of pigment particles to suppress passage of molecules and ions therethrough. Silica which is commonly used as an extender pigment for paint is selected. An amount of silica added is preferably in the range of 1 to 10wt.% relative to paint. When such amount is less than 1wt.%, the result of suppressing passage of molecules and ions is less effective, and when addition of such amount exceeds 10wt.%, a coat formation quality is degraded. A particle size of fine silica is 10μm or less, and is preferably 6μm or less. When 10μm is exceeded, a filling result is made less effective. Addition of silica can prevent generation of coat blistering upon application of corrosion prevention to cathode.;COPYRIGHT: (C)1994,JPO&Japio