Sometime in 2012 I was engaged in a conversation on a Professional Water Treatment Forum. The subject was about pre-passivated corrosion coupons. For those of you who are unaware, Corrosion Coupons are used by property owners and by water treaters to monitor the effectiveness of a water treatment program’s ability to prevent or control corrosion. Ideally, the coupons are matched to the metal type that the program is trying to protect. Ideally, the corrosion of the coupon should be at the same rate as the system metal to be able to monitor the actual corrosion taking place in the system. In many cases matching the corrosion rate in the system is not possible and the coupon will corrode more rapidly than the system metal. This is because the system has an established oxide coating that protects it while the coupon does not. But it is okay if the coupon corrodes faster, since the higher sensitivity to corrosion will allow you to monitor the effects of changes in the water treatment program more quickly and with greater accuracy. Minimizing the corrosion rate on the coupon will, of course, minimize the corrosion rate on the system provided that they are the same metal.
At this point someone asked where they could buy pre-passivated corrosion coupons. The alleged purpose of pre-passivating corrosion coupons is to more closely match the corrosion rate to that of the system metal. In effect this decreases the sensitivity of the corrosion coupon to actual corrosion. The problem is that there exists no standard for properly passivating a corrosion coupon to match the corrosion rate of the system metal.
Typically the pre-passivation has been done in the past to deceive the water treatment company’s customer into believing that the water treatment company is doing a better job than it is actually doing in the control of corrosion. This practice had been common place in the 1970s.
To my surprise a number of company representatives admitted to using the pre-passivated corrosion coupons, and even more expressed an interest in where they could buy them. I was shocked and disappointed that so many were cheating or wanted to cheat their customers.
I am not sure how wide spread this practice of deception is. Many simply remained silent on the subject. But this speaks volumes regarding the importance of using an independent laboratory to monitor corrosion results. It is unwise to allow your water treatment company to give themselves a grade where your equipment is concerned.
We can provide a full range of pre-weighed corrosion coupons along with an independent laboratory analysis and technical backup to monitor your program. Click here for our corrosion coupon options.
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dhouriganMember Since 14 Jun 2012
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