Anti-corrosion coatings: nanotechnology will play a key role in the corrosion inhibitor market as new technology is developed.Used to protect everything from bridges and towers to water treatment facilities, anti-corrosion coatings and corrosion inhibitors are vital to maintaining a community's infrastructure.
Developing products that will safely and effectively protect the public from corrosion is a constant challenge. Formulators must deal with the challenges of rising raw material prices and increasingly strict environmental legislation. These two issues have had a profound impact on the anti-corrosion market, leading anti-corrosive coating makers to reformulate to reduce the amount of pricey raw materials, as well as develop products that will meet current and impending environmental legislation.
According to Tony Gichuhi, R&D manager at Halox, a key issue affecting the market is improving the efficiency of anti-corrosion coatings while maintaining a lower raw material cost by utilizing fewer raw materials, raw material consolidation or simply using lower cost alternative raw materials with superior performance or quality.
"Green chemistry is another major trend," Gichuhi added. "The market is demanding environmentally friendly, unregulated and nontoxic products for anti-corrosion coatings."
"The most challenging issue today has been the increase in raw materials, specifically the metal complexes, as well as the ever changing regulatory arena," agreed Lars Kirmaier of Heubach. "New environmental labeling concerns in Europe will have a wide reaching effect throughout the world in the next few years."
The rising cost of metals, particular zinc, molybdenum, lead and chromium used in anti-corrosion coatings and regulation of VOCs and heavy metals such as hexavalent chromium have forced anti-corrosion makers to reformulate. "Customers have no choice but to reformulate to account for VOC emissions and tighter regulation of heavy metals," Gichuhi said.
"While cost increases have impacted corrosion inhibitors, resins and other additives have influenced the formulator as well," Kirmaier said. "Since anti-corrosive pigments are formulation specific, this will drive the need to look at inhibitors which have a broad range of applicability. As business conditions get tougher for all aspects, Heubach will rely on innovations and application experience to assist our customers in successfully achieving their goals."
According to London Metal Exchange statistics, the price of zinc has gone up more than 240% in the last year. "Because the cost of zinc metal is rising, the cost of zinc phosphate is also rising," said Kirmaier. "Due to that dramatic increase, focus was placed on the development of zinc-free anti-corrosives."
R&D Focuses on Nanotechnology
Anti-corrosive coatings makers are looking to improve efficiency of coatings through the use of nanomaterials to enhance barrier properties, corrosion resistance and also utilize less coatings.
Halox is designing and creating smart materials focused on renewable raw materials, investing in materials generally regarded as safe (GRA) by the Food and Drug Administration and inventing nanotechnology additives with increased functionality. Halox is also educating customers on formulating with chromate-free alternatives and how to formulate correctly and avoid hazardous labeling of finished products.
"We are creating low cost specialty products to compete in a commodity driven market by underscoring the value-added benefits of the new products," said Gichuhi.
"Nanotechnology will play a role in the corrosion inhibitor market as new technologies develop, such as Sol-Gel Systems," said Kirmaier. "The incorporation of conductive polymers in lieu of corrosion inhibitors may occur in specialized applications. There are some interesting approaches of the nanotechnology expected due to the electrochemical properties, but the cost and handling are obstacles that have to be overcome first."
"Nanotechnology will most likely include some interesting future perspectives for anti-corrosion applications, but the feasibility of that technology for industrial use especially in respect to the handling and costs has not yet been proven," said Kirmaier. "Heubach is in close contact with different universities and institutes, who are engaged with nanotechnology and will certainly participate in one these projects as soon as any industrial usage comes closer to reality."
Heubach has introduced a zinc-free alternative for zinc phosphate for applications where the utilization of a zinc phosphate is not specified, for instance some industrial applications, where normally the pigment loading of zinc phosphate is low in the formulation.
"The decision to introduce a zinc-free Calciumphosphate CP on the market had been made quickly, because of the pressure from exorbitantly increasing zinc prices," said Kirmaier. "Our intention was to offer a zinc-free alternative for zinc phosphate for applications where the utilization of a zinc phosphate is not specified, for instance some industrial applications, where normally the pigment loading of zinc phosphate is quiet low in the formulation, because of the strong price pressure on such protective coatings."
Heubach has also introduced two new corrosion inhibitors based on modified phosphates for universal applications. While they are formulated to meet the newer demands of the protective coatings industry such as waterborne, powder and high solids, these products will also meet the requirements of conventional systems.
Halox has introduced a number of new products. Halox 750 is a hybrid inorganic-organic corrosion inhibitor for general light duty and industrial maintenance; Halox 900 is a patented surface pretreatment, rust preventative for steel and aluminum containing no nitrites or phosphates and Halox 430 is a patented versatile heavy metal-free corrosion inhibitor for coil coating, powder coatings, water- and solventborne coatings, aerospace, automotive refinish and general industrial coatings.
The Importance of Surface Preparation
One of the most crucial steps in applying anti-corrosive coatings is surface preparation. "The surface preparation of concrete for wastewater environments is a vital component of the application process to ensure the concrete meets the appropriate degree of cleanliness, strength, profile and dryness prior to coating," said Vaughn O'Dea, technical sales manager, water/wastewater for Tnemec.
To deal with this important issue, industry standards have been developed, such as the SSPC-SP13/NACE No. 6 Surface Preparation of Concrete, to ensure complete and consistent surface preparation throughout the industry.
"However, one critical aspect of the surface preparation process that is often overlooked is the need to fill air voids, bugholes, and other surface cavities at the concrete surface prior to coating," said O'Dea. "Otherwise, the coating is subject to bughole-induced outgassing, a phenomenon occurring when applying protective coatings to concrete (predominately vertically cast-in-place) where air becomes entrapped within bughole cavities and releases into or through the protective coating, thereby causing pinholes and holidays in the coating film. To alleviate bughole induced outgassing, a material must be forced into the bughole cavity, to displace the air within."
To protect wastewater infrastructure from biogenic sulfide corrosion, Tnemec Company developed Perma-Shield, a versatile product line of 100% solids epoxy coatings designed with exceptionally low H2S permeability and [H.sub.2]S[O.sub.4] resistance.
"Series 434 Perma-Shield [H.sub.2]S is a 100% solids trowel applied epoxy mortar; Series 436 Perma-Shield FR is a 100% solids fiber-reinforced high-build epoxy liner with spray application capabilities; and Series 435 Perma-Glaze is a 100% solids multifunctional polyamine epoxy designed to be applied to steel, concrete, or as a glaze coat over the Series 434 or 436," said O'Dea. "The Perma-Shield materials performed superbly in the Tnemec Severe Wastewater Analysis Test, a laboratory testing program simulating the effects of elevated hydrogen sulfide gas and sulfuric acid on coating systems used in severe wastewater environments."