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38 DECEMBER 2016 MATERIALS PERFORMANCE NACE INTERNATIONAL: VOL. 55, NO. 12 of the IOZ prior to topcoating. In some in- stances, because of these issues, major asset owners have chosen to omit IOZ primers from project specifications and use zinc- rich epoxies instead. Over the past 50 years, formulation ad- vancements have yielded incremental suc- cesses in lengthening application windows and decreasing cure times for IOZs. Re- cently, a study by formulators with Hempel A/S (Lyngby, Denmark) was undertaken to improve the application characteristics of IOZs with a primary focus on reducing mudcracking due to overbuild, as well as shortening long cure times. Because the mechanical properties of coating formula- tions are significantly improved by fiber reinforcement—coatings reinforced with fibers exhibit good mechanical properties resulting in higher film strength and im- proved crack resistance, especially at areas with excessive film thickness—the formula- tors proposed that an inorganic mineral fiber reinforcement filler be added to the IOZ formulation. e idea was that an inorganic mineral fiber could reduce mudcracking, improve impact resistance, improve flexibility, and support additional formulation modifications that decrease cure times. e formulators identified an inorganic mineral fiber with the ideal strength, type, shape, and size to accommodate the use of existing air spray or airless spray applica- tion equipment. ree experimental for- mulations with a constant zinc pigment volume concentration and varying amounts of fiber, as well as a standard ref- erence formulation, were tested. All exper- imental formulations contained zinc load- ing of 85% or more zinc dust by weight in the dried film. e experimental IOZ formulations and reference IOZ coating were applied to car- bon steel panels that had been grit blasted to NACE No. 1/SSPC-SP 5, "White Metal Blast Cleaning." A climate-controlled paint booth was used to ensure ambient condi- tions of 23 °C and 75% relative humidity during coating application and cure. Each sample coating, including the reference coating, was applied at varying thicknesses up to ~900 µm wet film thickness and al- lowed to cure. After cure, DFT measure- ments were taken and the panels were Continued f rom page 37 COATINGS & LININGS It's Been a While Since High School Math Class… Are Your Mental Math Skills Up to Par? Find out at: nace.org/math Here's your refresher and digital crib sheet: NACE's Math for the Coatings Professional. In this short online course, brush up on those critical functions and calculations needed to perform coatings work accurately and more efficiently. Choose between two version, imperial and metric, to see if you measure up: • Math Principles (decimals, fractions, percentages, exponents, order of operations) • Basic Coating Calculations (sq. footage, volume) • Advanced Coating Calculations (theoretical and practical coverage, DFT, WFT, adding thinner) • On-the-Job Calculations