Galvanic corrosion resistant insulating pipe having excellent film adhesion

摘要

A low corrosion resistant pipe 1 is jointed with a high corrosion resistant pipe 2 directly or via a coupling 3. An insulating ceramic film having a thickness of 0.4 mu m and a resistivity of 108 OMEGA cm or more is formed on the outer and inner surfaces of the pipes 1 and 2 at a length L of 60 mm or more from the end of the pipe and on the surface which forms a space when the pipes 1 and 2 are jointed at a coverage ratio of 90% or more to less than 100%.