How do medical device springs generally avoid surface corrosion? Generally, the metal protective layer is obtained by surface treatment and electroplating. This electroplated protective layer can not only avoid corrosion, but also make the entire medical device spring more beautiful. So let's learn more about why the springs of medical devices need to be surface treated.
Medical equipment springs can also improve the working performance of the springs during metal plating, such as increasing the surface hardness of the springs, increasing the spring's abrasion resistance, improving the thermal stability of the medical equipment springs, and preventing spring rays from corroding. But if it is purely for the corrosion of medical device springs, electro-galvanized layer and electro-cadmium layer should generally be used.
Zinc is relatively stable in dry air, hardly changes, and is not easy to change color. In humid air, a white film of zinc oxide or carbon zinc carbonate is formed. This dense film prevents the spring from continuing to be corroded. Therefore, the galvanized layer is used as the anti-corrosion protective layer of the spring under normal atmospheric conditions. All springs that are in contact with solutions such as sulfuric acid, hydrochloric acid, caustic soda, and working in humid air with sulfur trioxide and other atmospheres are not suitable for zinc plating.
The cadmium-plated layer is brighter and more beautiful than the zinc-plated layer, is softer, and has better plasticity than zinc, and the cadmium-plated layer has less hydrogen embrittlement. But cadmium is scarce, expensive, and cadmium salt is highly toxic, which is very harmful to the environment. Therefore, it is restricted in use. Most of the springs used only in aviation, navigation and electronics industries use cadmium plating as a protective layer.
In addition to the above-mentioned zinc and cadmium plating, the metal protective layer of medical device springs also includes copper plating, chrome plating, nickel plating, tin plating, silver plating, zinc-titanium alloy plating, etc. The spring designer can choose according to the spring working occasion Plating.