硬ろう付けに用いられるリン銅ろうの耐食性に及ぼす溶融温度の影響

抄録

Water leakage in heat exchangers due to the progression of groove corrosion near the joints of copper tubes bonded by copper–phosphorus brazing can lead to a number of serious problems. Brazing is often done by hand, resulting in variations in the melting temperature of the brazing material. This study was performed to examine the effects of melting temperature on the corrosion resistance of copper–phosphorus brazing filler material used for hard brazing. Examination of the metallographic structure of copper–phosphorus brazing material revealed differences in structure before and after melting. However, there were no significant differences in structure between samples melted at 750°C and 800°C. Anodic polarization curve and corrosion potential measurements showed microstructural changes after melting, but there were no significant differences between melting at 750°C and 800°C. The microstructural observations and electrochemical measurements suggested that melting temperature has only a minimal effect on corrosion resistance of copper–phosphorus brazing filler material.