Measuring and Reducing Corrosivity

Apr 8

One case I was involved in related to corrosion of aluminium from a flame retardant. This flame retardant had been invented and developed by a North American company, who wanted to commercialise their product within the world of flame retardants. For one particular application, which had significant expected volumes, the flame retardant product had to meet certain anti-corrosion goals against steel and aluminium. I was hired by this client to evaluate the corrosivity of their product against steel and aluminium, in accordance with given test methods. Matchbox sized coupons of steel and aluminium were prepared by cleaning them mechanically and chemically, before they were immersed in the flame retardant liquid for 30 days. By weighing the coupons before and after testing, the mass loss of the coupon was measured, from which a rate of corrosion was calculated and compared against the given limits.

It was found that the flame retardant liquid had little effect on the steel, but was overly corrosive against aluminium. This had to be addressed. Some minor compositional changes to the liquid flame retardant were trialled initially, but it quicky became clear that a corrosion inhibitor would have to be acquired. However, there were some limitations. The efficacy of the flame retardant and it’s physical properties could not be compromised, and certain ecological benchmarks had to be met. Some “off the shelf” products were trialled, but it quickly became clear that the corrosion inhibitor would have to be somewhat specialised.

I engaged with one of the suppliers of the off the shelf products we had trialled, a company named Ascotec, to make some modifications to one of their products which had performed well. Because of non-disclosure agreements around both the liquid flame retardant and the corrosion inhibitor, we could not evaluate compatibility on a theoretical level, so trial and error was required in evaluating any changes to the corrosion inhibitor. Some changes led to obvious compatibility issues, others were less obvious, only becoming apparent after 14 days of viscosity tracking, and others required a long-term corrosion test to evaluate fully.

The process was slow, but ultimately successful. With the dedicated help from Ascotec, we were able to achieve the corrosivity goals set out by the client, with minimal changes in the physical properties of the fire retardant liquid.

Do you need to measure the corrosivity of a product? Are you trying to prevent corrosion in an application? Maybe corrosion has already taken a foothold? We can help with all of these and more!