custom masking products
Published

Electrocoat Q&A: Eco-Friendly Pretreatment Systems

Which pretreatments work with electrocoat systems?

Jose Tirado, Consultant, Ti6 Consulting International

Share

Q. We have been approached several times by pretreatment suppliers about the possibility of switching our zinc phosphate pretreatment to a more eco-friendly pretreatment for our electrocoat. Are those pretreatments compatible with electrocoat systems?

A. I believe that the pretreatments you are talking about are thin film pretreatments. Like zinc phosphate systems, thin film pretreatments provide enhanced adhesion to bare metallic substrates as well as additional corrosion protection when used with epoxy electrocoats. The thin film pretreatments were primarily developed for electrocoating systems processing mixed loads of ferrous and nonferrous metal substrates.

Thin films pretreatments deposit protective films between 10–50 mg/ft2 as opposed to the typical 200–400 mg/ft2 level for zinc phosphate systems. In addition to the lower coatings weights, thin film pretreatments produce almost zero sludge, less overall environmental footprint (no phosphates and no heavy metals) and lower application temperatures. Because of CAFE standards in the U.S., the resulting lower part weight is also a benefit to OEMs, because it reduces the overall weight of vehicles and increases fuel efficiencies. Adhesion, appearance, corrosion performance and cost are practically the same for both types of pretreatments.

When the low film pretreatments are formulated with hard metals such as titanium, zirconium or others, the thin film layer provides substrates with higher surface conductivities than substrates pretreated with a conventional zinc phosphate systems. This is excellent news for electrocoat systems. The increased conductivity of the substrate allows the electrocoat system to operate and deposit ecoat film at lower deposition voltages, and therefore operate at greater coating efficiencies and lower costs.

Many automotive OEMs are currently switching their body-in-white (BIW) lines from phosphate pretreatments to thin film pretreatments. These pretreatments have been gaining increased acceptance by OEMs lately, and the expectation is that this trend will continue to grow at an accelerated pace in the coming years. General purpose electrocoat part lines seem to be lacking behind on the technology transition efforts. 

Originally published in the December 2015 issue.

 

Related Content

  • NASF/AESF Foundation Research Project #122: Electrochemical Approaches to Treatment of PFAS in Plating Wastewater - 7th Quarterly Report

    The NASF-AESF Foundation Research Board has selected a project on addressing the problem of PFAS and related chemicals in plating wastewater streams, studying PFAS destruction via electrooxidation and electrocoagulation.  Our last report described the results from experiments of EO with a Magnéli phase Ti4O7 anode on the degradation of eight perfluoroalkyl acids (PFAAs).  In this seven quarter report, we describe work to further explore how the degradation of different PFAAs are related to their molecular structures.

  • Defoamer Designed for Waterborne Coating, Printing Ink Formulations

    Evonik’s Tego Foamex 812 exemplifies the company’s sustainability strategy for the paintings, coatings and inks industry.

  • NASF/AESF Foundation Research Project #122: Electrochemical Approaches to Treatment of PFAS in Plating Wastewater - 6th Quarterly Report

    The NASF-AESF Foundation Research Board has selected a project on addressing the problem of PFAS and related chemicals in plating wastewater streams, studying PFAS destruction via electrooxidation and electrocoagulation.  This sixth quarter report covers the continued assessment of eight perfluoroalkyl acids PFAAs most commonly found in wastewaters, by electro-oxidation with a Magnéli phase Ti4O7 anode across a range of anodic potentials in solutions, exploring the reaction mechanisms.  To summarize, the PFAAs start to exhibit degradation behavior when the anodic potential reaches a level where water oxidation occurs, suggesting that the hydroxyl free radicals generated via water oxidation play a role in PFAA degradation.

Your Best Finish Starts With Us!
New Acid-Free Bright Nickel Process
Heatmax Heaters ad with immersion heaters
Heatmax Heaters ad with immersion heaters
find masking products online
PMTS 2025 Register Now!
OptiCenter All-in-One OC11
PF Podcast
Heatmax Heaters ad with short lead times