From the perspective of the durability:
1. the best material should be stainless steel, which become more and more shining especially when used as the surface material. It has very good strength, strong corrosion resistance, and unfading color. But there are varieties of stainless steel: the two main kinds are ferrite and austenite. Ferrite stainless steel, commonly known as stainless iron, is magnetic, but when used for a long time or under the bad environment, it will rust. Only the austenitic stainless steel does not rust, and identification method is simple, just using magnet.
2. The copper is one of the most widely used lock material, with good mechanical performance, corrosion resistance, processing performance, gorgeous color and luster. Especially the copper forging handle and other lock decoration have smooth surface, good density, no pores and sand holes. It is both solid and antirust and can be used to plate 24 k gold or gold dust and other surface treatment. It looks gorgeous, noble and generous, adding many colors to people's furnishing.
3. Zinc alloy, its strength and anticorrosive capability is not so good, but its advantage is easy to make design of complex parts, especially pressure casting. There is a strong possibility that the locks with complex pattern in the market is made of zinc alloy, so consumers have to identify carefully.
4. Steel, with good intensity and lower cost, but easy to rust, generally used as lock internal structure materials, unfavorable for external decoration.
5. Aluminum or aluminum alloy, ordinary aluminum alloy (excluding aerospace) soft and light, with low material intensity, but easy to process and shape.