Corrosion means certain death for anything composed of a material — from structures such as bridges and buildings, to critical pipelines, electronics and historical monuments, for instance.

Known as the gradual degradation and deterioration of materials via chemical or electrochemical reaction with the material’s surroundings, corrosion is oftentimes largely identified as something that only affects metal surfaces. Yet, corrosion is common with all sorts of materials, including stone, ceramics and polymers. However, in those instances, it is often referred to as degradation.

Corrosion is commonly characterized by rusting on iron objects, tarnishing on silver and pitting or cracking on other surfaces, according to the material type and the atmospheric conditions that the material encounters. No matter the byproduct of corrosion, the end result is largely the same: degradation of material strength and appearance, and increased permeability to liquids and gases.

To increase the lifetime of materials, and, consequently, a host of structures and devices, researchers the world over have sought out a variety of anti-corrosion solutions. Follow along with GlobalSpec as we explore some of those anti-corrosion solutions in this two-part feature.

Robots

Texas-based tech startup Alicia Bots has developed magnetic crawler robots capable of autonomously performing anti-fouling hull grooming on ships.

Source: Alicia Bot

The Roverclean 3.0 magnetic crawler robots, which are guided by artificial intelligence (AI)-powered analytics, are expected to reduce hull fouling on ships, which will subsequently reduce fuel consumption, costs, carbon emissions and corrosion.

Collar

Although this next solution may not prevent corrosion entirely, it will help to detect it before it becomes a potentially larger, more invasive problem. A pipeline collar developed by researchers from the Southwest Research Institute (SwRI) in San Antonio, Texas, can detect anomalies in oil and gas pipes, locating leaks, such as those due to corrosion, before they occur.

The current iteration of SwRI’s Magnetostrictive Transducer (MsT) Collar, which relies on SwRI’s Magnetostrictive Sensor (MsS) technology, uses ultrasonic guided wave technology — a noninvasive rapid testing approach for detecting, locating and classifying corrosion defects — to detect anomalies in pipes.

According to its developers, the MsT Collar can consistently monitor the condition of pipes with the potential for preventing leaks from developing altogether, according to the SwRI team.

Source: SwRI

The new design of the MsT Collar is thin, flat and capable of withstanding temperatures up to 400° F. Further, eight sensors enable the transducer to more accurately locate where corrosion occurs on the pipeline.

Using magnetostrictive sensors, which produce and subsequently receive guided waves that transmit along a structure, guided by its boundaries, the researchers determined that guided waves will enable hundreds of meters of pipeline to be inspected from one location.

Tomatoes

Researchers from the Spain-based Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-CSIC-UMA) and the Instituto de Ciencia de los Materiales de Sevilla (ICMS-CSIC-US) have developed a lacquer coating derived from tomato pomace for application to the inner surface of metal food packaging and food and beverage cans.

Steel and aluminum are the metals typically used for canned foods and beverages. However, the food contents of the can corrode the metal and thus contaminate the food. Currently, to protect against such corrosion, cans are typically coated with an adhesive resin called epoxy, a petroleum-based plastic featuring bisphenol A, which is more commonly known as BPA — an industrial chemical compound that protects food, but that also releases particles that impact human health.

Source: Journal of Cleaner Production (2022). DOI: 10.1016/j.jclepro.2022.135836

As such, the researchers have created an alternative coating for cans using by-products from tomatoes processed in the making of gazpachos, sauces or juices — a substance called tomato pomace.

To create the tomato-based coating, the team dried tomato pomace samples, which then underwent a hydrolysis process, wherein remaining water was removed, leaving behind vegetable fat.

After the vegetable fat was removed, it was combined with ethanol (ethyl alcohol) in an 80% water, 20% ethanol mix. The resulting dispersion of grease in the water was then sprayed onto the inside surface of cans in the lab. To encourage binding to the can, the researchers applied heat, subjecting the mixture to a temperature of 200° C for a 10 to 60 minute time frame.

In the lab, this biological and environmentally friendly tomato-derived resin reportedly repelled water, adhered to the inside of metal cans coated with it, demonstrated anti-corrosive properties against salt and any liquid, and did not leech into the food like BPA did.

Check back with GlobalSpec for part 2 of this feature on corrosion and the solutions being undertaken to prevent it. Part 2 will explore how coating technology, specifically, is helping to prevent the deterioration of materials.