Definition - What does Silica Gel mean?
This is a form of silicon dioxide that is viterious or porous in nature. It is used as a drying agent in corrosion prevention due to its ability to suck up moisture through capillary condensation or adsorption. Its high specific surface area makes it a useful and convenient desiccant or dehumidifier. Silica gel is available in various configurations depending on its application.
Corrosionpedia explains Silica Gel
For galvanic corrosion to occur, it requires two dissimilar metals: an electrolyte and a conductor-path to the metals. The material in use becomes the anode, which will lead to corrosion if the current flow is not stopped. The introduction of another metal, which will act as an anode, makes the protected substrate the cathode (hence the name "cathodic protection").
The importance of silica gel in cathodic protection is the reduction of the rate of hydroxyl ions formation. This is achievable by absorbing all the humid or moisture present around a metal. In the industries, the silica gel packagings are modified to change color depending on the saturation of moisture absorbed. The reusability of the material, through heating, makes them suitable for temporary corrosion protection methods.
Silica gel used as a desiccant is placed in permeable bags that are later used in containers or placed around the material to be protected against corrosion. It is mostly used to protect steel substrates as it has no chemical reaction with metals.