What's the chemical reaction between stainless steel and galvanized angle iron?
They are not the two reaction, after they are Unicom, there can be electronic flow, and zinc than iron lively, so galvanized angle iron is more likely to be corrosion (mainly air oxidation).
The essential condition for stainless steel to be corrosion resistant is that the mass fraction of chromium must be greater than 10~12%. When the temperature increases, the diffusion velocity of carbon in the grain of stainless steel is higher than that of chromium. Because the solubility of carbon in austenite at room temperature is very small, about 0.02% ~ 0.03%, and the carbon content in austenite stainless steel are generally more than this value, the excess carbon will continue to austenite grain boundary diffusion, and chromium compounds, compounds of chromium carbide in the crystals, such as 23C6 (CrFe) etc.. The data show that chromium diffusion along the grain boundary activation capacity of 162 ~ 252KJ/mol, and Cr intracrystal diffusion activation energy is about 540KJ/mol, namely: chromium by intracrystal diffusion faster than chromium diffusion along the grain boundary velocity is small, the chromium was too late to grain boundary diffusion, so the main chromium chromium carbide formed in intergranular required not from the austenite grain interiors, but from the vicinity of the grain boundaries, the chromium content makes near the grain boundary is reduced, when the mass fraction of the grain boundary chromium low to less than 12%, the formation of the so-called "chromium depleted zone", in corrosion, will lose the chromium depleted zone corrosion resistance, and intergranular corrosion.
Stainless steel and galvanized steel angle, if it is bolted, it is best to add non absorbent insulation gasket.
