The Effect of Nocolok Potassiumfluoridezincate Flux on Evaporator Corrosion Resistance 2005-01-2034
Heat exchanger requires both high quality level and high performance. In order to manufacture heat exchanger, aluminium brazing technology is often used. Moreover to improve compactness and lightness, the material thickness of the heat exchanger components tends to decrease. However, it is necessary to maintain high quality level in particular regarding corrosion resistance.
In order to improve the corrosion resistance of heat exchanger, several methods are used. One of the possibilities is to use multiclad material with a corrosion protection layer. Other methods propose to use a modified Nocolok flux. This modified Nocolok flux during melting creates zinc particles. The zinc particles react with the aluminium alloy surface during the brazing cycle and create an external layer with better corrosion resistance due to local corrosion potential modification.
In this framework a study is proposed to define the effect of Nocolok zinc flux on evaporator external corrosion behaviour (“plates to fin”). The cladded outer surface of plate is used as a filler material during the brazing. The particularity of this study is to evaluate the effect of Nocolok zinc flux with cladded material.
Several parts have been made. The corrosion resistance has been estimated by SWAAT (See Water Acid Acetic Test). In parallel brazing performances have been studied (metallographies, burst pressure, diffusion rate). An analysis of the results and further works are proposed.