Corrosion develops when two dissimilar materials are combined in a corrosive electrolyte. This can occur when certain materials (such as aluminum) are in contact with stainless steel.
The most common solution to prevent galvanic corrosion is to select metals that are close together in the galvanic series. Separating the metals that are incompatible reduces the risk of these cells deteriorating. According to the levels of galvanic corrosion, stainless steel that comes into contact with materials such as copper is less likely to be a risk than when it is in contact with aluminum.
Although aluminum reacts negatively to stainless steel, large surface areas of aluminum to stainless steel can be acceptable depending on local environmental conditions. Severe corrosion is likely to take place in a marine environment. However, there are methods that can be used to reduce this effect. A good way to reduce corrosion is to use an isolating coating or paint on the aluminum and the steel to isolate them electrically. Insulating washers are also effective in isolating the two dissimilar materials and creating a relatively safe surface area.
Along with corrosion, discoloration of stainless steel may occur when combined with aluminum. This is also called ‘tea staining’. Discoloration can be prevented by the use of insulation and regular maintenance. Passivation can also be used to create the passive film on the fastener for better corrosion resistance.
As a leading stainless steel fastener specialist; and partnered with manufacturers and suppliers of the full range of stainless steel and aluminum use across all industries; Marsh Fasteners can help you ensure that you use the best products with the highest anti-corrosion qualities.