| 摘要 |
PURPOSE:To obtain the titled coating material causing less initial corrosion and maintaining the sacrificial anode effect after brazing over a long term by adding Fe and/or Ni to a coating material made of Al-Si-Mg-In alloy as a brazing filler metal. CONSTITUTION:The titled coating material is made of Al alloy contg., by weight, at least one of 0.3-2% Fe and 0.3-2% Ni besides 4-20% Si, 0.3-4% Mg and 0.02-1% In. By adding Fe and/or Ni, H2 generated during boehmite treatment for preventing initial corrosion after vacuum brazing is inhibited from entering the interior through the grain boundaries, and a perfect chemical coat is obtd. Less than the lower limit of Fe or Ni does not produce the effect, and more than the upper limit of Fe or Ni causes defects in the coat obtd. by said treatment and tends to break the coat. |
