Hard anodizing is a special type of electrochemical film-forming anti-corrosion in aluminum alloy anodization. The most significant difference from ordinary anodized aluminum is the oxide film thickness of the two: generally, the oxide film thickness of anodized aluminum is 5 -20μm, while the oxide film thickness of hard aluminum oxide is more than 50μm, and the maximum thickness can reach about 250μm.
The main purpose of hard anodizing treatment of aluminum alloys is to improve various properties of aluminum and aluminum alloys, including corrosion resistance, wear resistance, weather resistance, insulation and adsorption. It is suitable for both deformed aluminum alloys and die-cast aluminum alloy parts.
1. Oxide film thickness: The thickness of ordinary anodized film is 5-20um, and the thickness of hard anodized film can reach 50-200um.
2. Different hardness: the hardness of ordinary anodizing is HV250-350, and the hardness of hard anodizing is HV350-550.
3. The anodizing temperature is different: the temperature of hard anodizing is generally 5℃ and below. Relatively speaking, the lower the temperature, the higher the hardness; the temperature of the oxidation tank for ordinary anodizing is around 18-22℃, and with additives it can reach 30 ℃.
Hard anodized aluminum is mainly used in aluminum and aluminum alloy parts that require high wear resistance, heat resistance, and good insulation properties. Such as various inner walls of cylinders, pistons, steam plugs, cylinders, bearings, aircraft cargo compartment floors, roller rods and guide rails, water conservancy equipment, steam impellers, leveling machines, gears and buffer pads and other parts.