1) 7075-T651 aluminum alloy has a relatively high hardness, close to 1.6 times the hardness of 6061. After the aluminum is oxidized and blackened, it is wear-resistant, anti-corrosion, and resistant to straight lines and hand sweat. As long as the parts are not too thin, they are the first choice. The size of parts that have been oxidized by aluminum will become smaller. As long as you grasp the law of change, you can increase the size appropriately during machining.

2) If the 7075 aluminum alloy is still thin in terms of mechanical strength, it is necessary to use steel for quenching and tempering heat treatment. Black nickel or black chromium plating can be used. The bottom plating should have 25 micron copper and 12 micron nickel. . This kind of coating can also prevent hand sweat, wear and corrosion.