Dirt and surface state is varied, due to the type of the combined forces combined with strong degree is different, so easily remove dirt from the object surface is also different.
The metamorphic layer formed in the surface dirt metal is placed in moist air will rust, rust scale this dirt is not from the outside environment, but objects react with surrounding environment material formed on the surface of the layer.
The characteristics of the dirt is often between dirt metamorphic layer and substrate has a clear interface, thus can be used by the chemical reagents such as acid, alkali or the metamorphic layer with physical mechanical methods, remove dirt from surfaces.
On pure gravity on an object's surface subsidence and the form of dirt that has accumulated foreign impurities, on the surface adhesion is very weak, easy to remove from the surface, such as clothes or furniture surface on the thick dust particles.
By adsorption combined with the dirt on the surface of the object in this case the dirt molecules and the adsorption force between molecules on the surface of the object, the adsorption force could be both the van der Waals forces between the molecules, may also be intermolecular hydrogen bonding interaction or covalent bond is formed between the molecular junction.
When combined with dirt on molecular adsorption on the surface, especially combined closely with the dirt in thin film form on the surface, the binding force is very strong.
Direct contact with the surface of the dirt layer due to the strong adsorption of the cleaning method often used is very difficult to remove them.
And the smaller dirt particles exist in this state, and also the stronger adsorption on the surface of the object, in the ultra precision industrial cleaning need this class to remove any small dirt particles, therefore to use some special methods to overcome dirt particles on the adsorption on the surface of the object.
Prick surface and wedge into the internal hard dirt such as metal cutting debris and wedge surface grinding powder, coating the surface of the train car can be train wheel and rail friction produces in the process of iron powder to Pierce.
Before the above three conditions usually referred to as' attached dirt and grime from the environment and there is an object with a clear interface, this dirt removal will not cause any damage on the surface of the object.
And called the three conditions after 'pollution dirt, due to dirt and object has become an organic whole repeatedly and go deep into the surface, therefore remove the dirt to carefully select the appropriate cleaning method, not only to remove dirt, and try to avoid the surface damage.
Dirt particles are attached to the surface by electrostatic attraction when dirt particles and surface with opposite electric charge, it will depend on the electrostatic attraction to the object surface sometimes dirt particles and surface adsorption with the same negative charge, but the surface is positively charged metal cation, this time by the middle of the metal cation, dirt particles adsorbed on the surface will also depend on the electrostatic attraction indirectly.
Many poor conductivity surfaces tend to take charge when placed in the air, and the dirt from the charged particles will by electrostatic adsorption to the object surface gravity.
When will the class object immersed in water.
Because there is a lot of water when the dielectric constant can make the dirt and electrostatic attraction between the surface greatly weakened: at this point the dirt easily disintegrate from the surface.
This class composed of poor conductivity of material objects in solution after cleaning, if placed in the air environment makes it dry, and it will probably be charged dust particles pollution.
To avoid this kind of situation, in the ultra precision industrial cleaning technology, this kind of objects after the cleaning process is placed in the clean room is very clean and dry.
Infiltration of surface liquid dirt on the surface of the internal dirt such as clothing, not only spread in the clothing surface wetting, at the same time also to the clothing fibers internal diffusion.
The infiltration of objects will be confronted with more internal dirt removal difficult.