- How to protect the vehicle from corrosion by using zinc coating and cathodic protection
How to protect the vehicle from corrosion by using zinc coating and cathodic protection
Corrosion of metal pursuing the vehicle, starting from the moment of his birth. To slow down this process, you can use cathodic protection and galvanizing.
metalcathodic protectionsurface metalelectric currentmetal partsprotect body
In addition to chemical corrosion when oxidation of the metal takes part of the oxygen contained in the air, chemical impurities, iron is suffering from electrochemical corrosion.
Water falling on the metal surface, contains various dissolved salt is an electrolyte. When the contact of the metal with the electrolyte an electric current, which triggers the electrochemical reaction, is slowly but surely turning metal into iron oxide (rust).
The laws of nature cannot be undone, the metal will inevitably be oxidized. The only way to slow down its destruction – to put between it and the environment a kind of barrier. About technology and ways to create this barrier further and speech will go.
Protection of metal surfaces by the application of the zinc coating is one of the most secure technologies to protect them from corrosion. Hot-dip galvanizing is done by dipping metal parts in a container of molten zinc, for galvanic galvanizing is used the effect of galvanization, in which metal surface, immersed in a special solution through which is passed an electric current, a thin layer of zinc.
The method of cold galvanizing is applied to the surface of the metal parts of the primer or paint containing finely divided zinc.
Often, in order to protect the bodywork from corrosion during its manufacture use tsinkrometall representing steel sheets, which even before the production of these parts is covered with a layer of zinc, and then subjected to welding, stamping and painting.
It is necessary to distinguish the concept of "full zinc body and zinc body". In the first case, a protective layer covered the entire surface of the body, in the second – only the most corrosion sensitive parts (sills and bottom).
The technology of cathodic protection is based on the ability of the more active metal (anode) under the influence of an electric current to release electrons, which are less active metal (cathode) attaches to its ions. As a result, the anode will be depleted and korrigirovat, and the surface of the cathode is covered with a protective layer of metal of the anode.
In practice it looks so: to the surface of the body is attached the plate of zinc or magnesium, it serves a positive potential of about 0.2 V, and the body of the car is the same, but negative. As a result, the particles of zinc or magnesium under the influence of electric current will be transferred from the plate to the anode to the surface of the body, protecting it from corrosion. The protection process will proceed as long as the "sacrificial electrode" (the anode) is completely depleted and will not collapse.
Method of cathodic protection is used for hard-to-reach parts of the body, to protect from rust which in other ways is not possible. These include the inner part of the wings, boot, bonnet, sills, underbody, doors and ceiling of the cabin.
In addition to the considered technologies to protect the body from corrosion, widely used coating the surface of metal parts wax, paraffin wax and liquid oils, the processing of the underbody, sills and wheel arches mastics and liquid plastic, drawing of polymers on the wheel arch and edge of bonnet, priming, painting, barrier and lamination. However, this is the topic for a separate publication.
Good luck to you! No nail, no wand!