Advances in coating technology

Sheila Kennedy, contributing editor, explores thermal indicators, no-cure coatings, diamonds and plant batteries.

By Sheila Kennedy, contributing editor

New formulations, capabilities and application processes making their way onto the market are driving improvements in coating reliability, performance and economy. The developments are largely designed to reduce energy, materials and maintenance requirements while being easy on the environment.

Clean air compliance: Paint and coating manufacturers are bound by laws and regulations to minimize the volatile organic compound (VOC) content in their products. Ford Motor Co. engineers and suppliers responded by developing a new cost-efficient and low-VOC paint formulation and automated application process that is being rolled out globally.

A new protective coating changes color to provide a visual clue that pinpoints the source of a maintenance problem.

– Sheila Kennedy, contributing editor

Ford used to apply three layers of paint to its vehicles in separate process stages using bulky, energy-intensive equipment. The new 3-Wet paint technology allows primer, base and enamel coats to be applied sequentially while still wet, without manual intervention, in an integrated booth. The 3-Wet technology meets Ford’s quality standards for chip, scratch and etch resistance; durability; and appearance. The high-solids, solvent-borne paint formulation produces fewer pollutants than current waterborne and solvent-borne paints. The robotic application process eliminates equipment and associated pollutants and reduces the cycle time by 20% to 25%.

The new technology should produce 6,000 metric tons fewer CO2 emissions per year compared to waterborne systems and 8,000 metric tons fewer CO2 emissions per year compared to conventional high-solvent-borne systems. In addition, there’s a VOC emissions savings of 5% related to processing.

Temperature indication

A new protective coating changes color to provide a visual clue that pinpoints the source of a maintenance problem. For instance, refinery and petrochemical process equipment that operate at elevated temperatures might experience overheating because the interior refractory lining failed or it’s bypassing hot gases. Dampney Company’s silicone-copolymer Thurmalox 260 TIC Series coatings reveal the hot spots that indicate overheating by changing color.

Designed for temperature-indicating applications in the 400°F to 650°F range, Dampney’s heat-resistant, self-priming, VOC-compliant coating changes color permanently at predetermined temperature intervals of 25°F to 50°F, depending on formulation. The red, blue, yellow or violet coatings are corrosion-resistant and provide good weathering and UV stability.

Efficient application: The hang, spray and bake method of applying coatings to steel and other metals is labor- and energy-intensive and consumes large amounts of powder. Greenkote’s thermo chemical surface modification process requires 50% less energy and 90% less powder than regular diffusion coatings. The corrosion-resistant coatings can be applied to a range of base materials and are free of hexavalent chromium.

Greenkote’s patented metal coating method is a liquid-free process applied in bulk to save cost. The parts and powder are introduced to a rotating oven where the powder content and thermal cycle define the characteristics of the coating and surface. The result is a high-performance, low-cost alternative to existing coatings methods such as chemical or electro-deposition, CVD, PVD and diffusion. Cost savings compared to competing technologies are said to range from 20% to 70%.

Tunable deposition: A diamond’s exceptional strength, durability and chemical resistance make the mineral an appealing material for coatings used in harsh or demanding environments. sp3 Diamond Technologies has enhanced its ability to cost-effectively deposit or grow uniform diamond films. The company’s chemical vapor deposition (CVD) capability now includes diamond coatings ranging from super smooth nanocrystalline films (surface roughness less than 10 nm) to controlled microcrystalline films (surface roughness greater than 10 um). The films can be deposited on substrates including silicon carbide, cemented carbide, silicon, tungsten carbide and graphite.

In addition to providing coating services, sp3 sells its CVD diamond hot filament reactor technology to companies that want to apply diamond coatings in-house. The reactor tightly controls diamond growth and film properties, which reduces the heat generated during sliding friction and increases component reliability.

Novel engineering: Researchers at Uppsala University in Sweden have discovered a way to coat algae blooms to make environmentally friendly batteries. They found that Cladophora algae’s special cellulosic nanostructure serves as an effective coating substrate for battery applications. The cellulose structure has a large surface area that, when coated with a thin layer of conducting polymer, reportedly produced a battery that is virtually weightless and set new charge-time and capacity records for polymer-cellulose-based batteries. The research highlights the potential for eco-friendly, lightweight and cost-effective energy storage systems.

E-mail Contributing Editor Sheila Kennedy, managing director of Additive Communications, at Sheila@addcomm.com.

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