This is the third installment of a three-part series on corrosion. In the first part, I presented a basic overview of the corrosion process from a physics viewpoint. The second column defined the specific types of corrosion attack.
In this article, I will provide some insight into how to prevent or slow down the corrosion process.
But, before we discuss how pool technicians and builders can manage this issue, we must address the elephant in the room: Corrosion mitigation or control starts in the manufacturer’s engineering department. One must realize that engineering is, among other things, finding a balance between requirements that, at times, are mutually exclusive.
One example is zinc-plated parts with a dichromate passive coating. Two types exist — hexavalent chromate, the superior from a corrosion point of view; and the lesser but more environmentally acceptable trivalent chromate. Even though the hexavalent is superior in standardized corrosion testing, it is banned in many countries, preventing its use for everyday products and equipment.
Another example is brass alloys. Red brass is nearly immune to de-alloying or dezincification corrosion attack, but red brass alloys that are engineered for casting contain significant amounts of lead to facilitate the manufacturing processes. With lead banned in many countries, manufacturers can’t use it as a means of corrosion resistance.
Cost is always a factor. The need for a long product life while at the same time remaining at a cost consumers can afford is always a challenge.Read More