| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a copper tube suitable for a heat pump water heater hardly adhered with scales irrespective of a flow passage shape. <P>SOLUTION: In the surface treated copper tube 1, copper or a copper alloy is used as a substrate 11, and a coating 12 comprising a polyphosphate of iron, cobalt, nickel, tin, or the like is formed on a surface of a side contacting at least water being a medium. Since polyphosphate ions [PO<SB>3</SB><SP>-</SP>]<SB>n</SB>and metal ions Me (Fe<SP>2+</SP>, Co<SP>2+</SP>, Ni<SP>2+</SP>, Sn<SP>2+</SP>, or the like) elute into the water, bind again, and are adsorbed on a crystal growth surface of calcium carbonate CaCO<SB>3</SB>produced on a surface of the surface treated copper tube 1, growth of the calcium carbonate is inhibited, and a deposit to the surface treated copper tube 1 can be reduced. <P>COPYRIGHT: (C)2011,JPO&INPIT |
