Rubber lining corrosion prevention

If the environment slowly attacks either the substrate or the membrane, the interposition of a brick lining between the contained liquid and the substrate or membrane will reduce to a tiny trickle the amount of chemical that reaches the membrane or substrate. Corrosion products, if any, are trapped behind the brick and cannot be washed away to uncover further material to be corroded, so that the corrosion slows down and may eventually stop. Example In a dished bottom, cylindrical steel tank containing a mixture of acid and oil, the steel was lined originally with sheet natural rubber. The rubber lining swells as the oil enters it, but the brickwork holds it in place until the rubber has swollen into all the pores of the brickwork and blocked them preventing any more of the contained liquid from passing behind the brick. 

When there is a relative motion between the corroding liquid and the metal or rubber surface the rate of attack of the damage to the surface is increased. The process is called sweating off with the corrosion product thus exposing the base surface again to corrosion. Otherwise the corrosion product (as a newly formed protective layer) would have prevented or slowed down further corrosion, just as in the case of hypochlorous acid solution on natural rubber lining, where the protective corrosion products exhibit very low cohesion and as such prone to be wiped off by the liquid unlike wet chlorine or hydrochloric acid which form a strong layer of corrosion product well adhered to the rubber surface. 

It is, however, a cheap and readily available material which can be fabricated easily by well-established techniques. It is used as a base material for lining with rubber, glass, or plastic, or it may be coated internally with a plastic or a paint. In other instances it is used to support a thin layer of expensive material. In most cases it must be treated to prevent corrosion from the surrounding atmosphere. 

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