13.4.1 Introduction
Accelerated corrosive attack is often observed in crevices that are exposed to wet conditions. Assemblies joined together by fasteners are particularly prone to this type of corrosion due to the difficulty in avoiding crevices between the joint elements. However, it is possible to minimise the problem by preventing moisture from penetrating the crevice.
13.4.2 Methods of Avoiding Crevice Corrosion
It is recommended to avoid, where possible, crevices in design. If they cannot be avoided, it is important that they are covered with a continuous paint film. Thread sealants are very useful in combating crevice corrosion and in most cases a good paint film prevents the ingress of water.
It is important that joints are carefully cleaned and dried before assembly since even small amounts of debris can prevent mating faces from contacting, resulting in crevice conditions. Similarly any moisture trapped between joint faces is likely to initiate corrosion.