How to prevent water pump corrosion?

How to prevent water pump corrosion?
We can’t absolutely ensure the pump not corrode, only do reduce the extent of corrosion.So what’s the corrosion pump?And how to prevent?
(1) the wear corrosion: refers to the high velocity a flush on the surface of metal corrosion.Fluid scouring abrasion corrosion is different from the medium containing solid particles caused by abrasion.Produces in the operation of the pump in the wear, so we will try to USES the material with good abrasion resistance, in order to reduce the wear corrosion.Of course, different materials have different performance of wear resistance.
 
(2) the electrochemical corrosion, electrochemical corrosion is due to the metal electrode potential difference, between the heterogeneous metal contact surface of the battery, so that the anode metal corrosion electrochemical process.The measures to prevent electrochemical corrosion, it is using sacrificial anode, the cathode metal protection;The second is the flow of the pump had better use the same metal material.
 
(3) the intercrystalline corrosion, intergranular corrosion is a kind of local corrosion, is mainly refers to stainless steel chrome carbide precipitation phenomenon between grain.Intergranular corrosion of stainless steel corrosion resistance greatly.The measures to prevent intergranular corrosion is: the stainless steel annealing treatment, or ultra-low carbon stainless steel (C < 0.03%).
 
(4) uniform corrosion: uniform corrosion, it is corrosive liquid metal contact surface, the metal surface homogeneous chemical corrosion.This is the one of the most common type of corrosion type, is also one of the least harmful corrosion type.Uniform corrosion prevention measures are: take appropriate materials (including nonmetal), consider enough corrosion allowance when water pump design.
 
(5) the crevice corrosion, crevice corrosion is a kind of local corrosion, refers to the gap is filled with corrosive liquid, due to the gap of oxygen and (or) in a lower pH in the passive film of local damage caused by corrosion.The high content of Cr, M0 metal can prevent or reduce the crevice corrosion occurred.
 
(6) point corrosion, pitting corrosion is a kind of local corrosion.Caused by metal passivity membrane partial destruction of the metal surface in local area rapidly forming half spherical pits, this phenomenon is called pitting corrosion.Corrosion is mainly caused by a Cl.Can be used to prevent corrosion including M0 steel (usually to 2.5% Mo), and as a result of Cl content and temperature rise, M0 content should also be increased accordingly.
 
(7) stress corrosion, stress corrosion is refers to the stress and corrosion environment caused by a local corrosion under the joint action.
The measures to prevent stress corrosion is the high content of Ni (Ni;A 30%) > 25% Cr – Ni austenitic steel.
 
(8) : cavitation corrosion caused the corrosion of pump cavitation occurs cavitation corrosion.To prevent cavitation corrosion is the most practical and simple method to prevent cavitation.But can’t stop the pump cavitation, more or less in the operation of the pump will produce cavitation, for those who often pump cavitation corrosion, cavitation resistance of the material can be used, in order to increase its resistance to cavitation.