plified version of one or both of the two equations
might only apply to a very specified formula-package
combination.
Hence, the current, state-of-the-art corrosion science
is insufficient to allow substituting mathematical
models for corrosion tests/measurements, which
are the only reliable way to determine:
• Will the formula cause spray package corrosion?
• How fast will corrosion by the formula degrade the
package materials?
The empirical equations in Figure 1 and Figure
2 are complex because there are many factors that
determine if corrosion will occur and how fast it
will degrade package materials. In the next issue,
I’ll continue the discussion with the most common
types of spray package corrosion causing/contributing
factors. Please visit www.pairodocspro.com for more
information.
Thanks for reading and I’ll see you in August.
Spray
1Editor’s note: Gibbs free energy is a measure of the
potential for reversible or maximum work that may be done
by a system at constant temperature and pressure. It is a
thermodynamic property that was defined in 1876 by Josiah Willard
Gibbs to predict whether a process will occur spontaneously at constant
temperature and pressure. Source: ThoughtCo.com
July 2020 SPRAY 25
Figure 1: The probability equation to estimate spray package material
corrosion. Please see Corrosion Corner (SPRAY February 2019) for a
parameter-by-parameter discussion of this equation.