Search Results

Sacrificial anode alloy Al-Mn-Sn in Part 1 was applied to fin material of an evaporator brazed in vacuum. But corrosion potential of the fin became a less noble value of 20mV than tube (target above 50mV). As a result of studies, this is why Sn did not dissolve into the fin core material because of slow cooling rate after heating in vacuum. Moreover, when cooling rate is made below 30 Min. (610°C→70°C), Sn dissolved, at the same time corrosion potential of fin became a less noble value of above 50mV. Thus, evaporators made under such conditions show excellent resistance to corrosion.

The sacrificial anodic effect of Al-Zn alloy reduces markedly in aluminium heat exchanger as car air-conditioner manufactured by vacuum brazing conventionally used, as zinc elements preferentially evaporate in vacuum-heating. It was found that Al-Sn alloy had superior electrochemical characteristics than Al-Zn alloy (AA7072) as the sacrificial anodic material used in vacuum brzing. According to many experimental results, the new brazing sheet-fin with Al-Mn-Sn alloy core metal has been developed. This fin has favorable formability and prominent sacrificial anodic effect. Therefore, this fin is excellent material for car air-conditioner manufactured by vacuum brazing.