Research and Production Application of High Corrosion Resistance Anodizing Process for Red Copper and Aluminum Bronze Alloy

Abstract

To improve the appearance and corrosion resistance of T1 red copper and QAl9-4 aluminum bronze alloys， an aqueous solution of sodium hydroxide and ammonium molybdate was used as the working solution to anodize T1 red copper and QAl9-4 aluminum bronze alloys.The microstructure， primary composition，and metallographic structure of the anodic oxide film on both materials were characterized using scanning electron microscopy， energy-dispersive spectroscopy， and metallographic microscopy， facilitating the optimization of anodic oxidation process parameters.The comprehensive performance of the anodic oxide film was assessed through appearance inspection， adhesion strength testing， high-temperature resistance， and neutral salt spray tests.Results indicated that under conditions of an anodic oxidation current density of 1.0 A/dm2， duration of 25～30 min，and a temperature range of 80～90 °C，a black oxide film of 1～3 μm thickness capable of withstanding temperatures up to 400 °C was achieved.Properly sealed anodic oxide films on both materials impeded the diffusion of corrosive medium， improving the corrosion resistance of T1 copper by 6.0 times and QAl9-4 aluminum bronze alloy by 2.5 times.Production applications demonstrated that the process was stable and easy to operate， making it suitable for mass production of T1 copper and QAl9-4 aluminum bronze alloy products， meeting decorative， matte， high-temperature resistance and corrosion resistance requirements.

Keywords

• red copper|aluminum bronze alloy|copper oxide|anodize|sealing treatment|neutral salt spray test