Materials.Business Weekly ⚙️
October 12, 2021
Quote of the week: “I never did anything worth doing by accident, nor did any of my inventions come by accident; they came by work.” - Plato, ancient Greek philosopher, (428/427 – 348/347 BCE).
From The Editor's Corner
Sol-gel hybrid technologies are on the way to more sustainable anticorrosive coatings
Innovation as a tool to better position ourselves in the market
Innovation will be the ultimate tool facing challenges into the frame of the post-globalization era—a time of severe climatic, sanitary, and socio-economic threats and constraints. But luckily dipped into the Fourth Industrial Revolution. Corrosionists are working hard about that. An example relates to smart anticorrosive coatings. Nowadays, there are several fronts of R&D, including bioinspired coatings, electrodeposited barriers, new conversion films, other deposition techniques like chemical vapor deposition – CVD, or physical vapor deposition – PVD, and others less developed as the deposition procedures depending on precursors’ properties like volatility, reactivity, and decomposition options (vapor phase epitaxy, atomic layer deposition, etc.). Besides, one of the most exciting advances concerns the so-called sol/gel coatings. In this last instance, there is earlier news for 30-40 years ago. Mainly, the current century has been the scenery for increased efforts to develop organic-inorganic hybrid - OIH - sol-gel coatings for metal corrosion protection. Today, there are some products in the market, and such a business is becoming valuable. Proof of the growing importance of the market is the current list of leading market players, including some of the biggest multinational companies dealing with anticorrosive coatings and chemicals: PPG, Sherwin Williams, Akzo Nobel, 3M, Henkel, BASF, DowDuPont, Solvay, Fuji Chemical, and Mitsubishi.
A comprehensive review of anticorrosive OIH coatings was published by Figueira et al. Some years ago. The same author updated the paper and published a new review last year. In the end, it is easy to conclude that today Corrosionists have a new tool, but it is not well developed yet. Consequently, there are many challenges, and a lot of R&D must be developed, searching for many more achievements.
OIH sol-gel anticorrosive coatings
This is a family of surface films or coatings produced by a process that has a primary set of steps as follows:
● A solution of the precursors included segmented or quasi-continuous monomers and inorganic particles of metal oxides, glasses, or other ceramics, joint together with bioactive components in water, alcohol, or other solvents—the sol stage of colloidal particles in a solution.
● Gelation, polymerization by hydrolysis condensation, including bonding between organic and inorganic components, of semi-solid colloidal particles suspended in a liquid (xerogel). Most chemical bonds are covalent, but ionic, hydrogen, Van der Waals, and others are options.
● Application as a coating on a substrate as ceramic, metal, or plastic by spray, dipping, spinning, flow, roll, inkjet printing, doctor blading or blade coating, capillary, etc. They also show good oxidation control and chemical stability. They can be applied to substrates such as ceramics, metals, and plastics.
● Dehydration and drying by evaporation, heat extraction, solvent, or precipitation. Final curing and hardening.
Therefore, high-gloss, non-stick, and multilayer composite coatings are obtained, useful in many applications, including corrosion protection. A behavior related to a set of characteristics, such as:
● A physical barrier effect, keeping away from the substrate any pernicious electrolyte.
● A complex nanostructured matrix allows for low porosity, good rigidity, and good adhesion to the substrate.
● The possibility of added-value, including layers of few micrometers each one, containing different dopants or additives, looking for the expected functionality: Layers containing corrosion inhibitors, self-healing effect, anti-fungal, antibacterial properties, UV protection, etc.
● OIH as multi-functional materials allows the synergy of their components and simultaneously achieves hydrophobicity from organic precursors and hydrophilic behavior from the inorganic skeleton.
● Organic constituents achieve flexibility, lightweight, electrical isolation, and good impact resistance.
● Meanwhile, the inorganic constituents contribute to processability, mechanical strength, wear resistance, low dielectric constant, and thermal and chemical stability.
● Usually, a final, topcoat layer, with properties of a ceramic or glass: Dense, hydrophobic, hard, high gloss, eventually self-cleaning, and in a wide range of colors.
From the engineering point of view, there are also several reasons to justify the industrial growing interest in the OIH as anticorrosive coatings in agreement with the Circular Economy guidelines:
● Non-poisoning precursors.
● Good control of precursor’s stoichiometry.
● Some of the processes are free of water.
● Room or low processing temperatures.
● Very low environmental impact.
● More clean and non-hazardous waste.
● Free of post-processing stages.
● Cheaper than most of the other choices.
Current situation and opportunities
Nowadays, some commercial products and sol-gel coatings are being offered for emerging applications in sectors like solar energy facilities, electrical & electronics, consumer goods, automotive, building & construction, marine industry, medical & healthcare, but mainly for aerospace purposes. Applications many of the times related to anticorrosive behavior. The growing demand for environmentally friendly coatings, largely encompassed with more and more national and international stringent environmental regulations, is driving the growth of the sol-gel coatings market. The global sales in 2018 were estimated to reach USD $2.012 million, expecting a tremendous growth rate of about 11.23%, with sales of USD $4.925 million in 2026. For example, the automotive industry uses sol-gel coatings for applications of metal parts, paint surface treatments, metal structures, lamps, mirrors, plastic hoods, windshields, side mirrors, and rear-view mirrors.
Watching the OIH coatings as an anticorrosive tool, we can find that studies started in the 1990s. Throughout these three decades, most of the research has been focused on few monomers, basically two siloxanes, GPTMS or 3-Glycidoxypropyltrimethoxysilane and TEOS or Tetraethoxysilane. Concerning the substrates, Al alloys are the most studied because of the higher interest of the aviation industry. An example is a recent study by M. Paez et al. About an OIH coating modified with Ag nanoparticles protecting against biocorrosion of a 2024-T3 aluminum alloy. In addition, there are some studies on carbon steel and a little bite on Mg, Zn, and Cu alloys. Limitation to planar geometry is another fact concerning most of the studies developed until now.
It is easier to understand that the sol-gel technique applied to OIH anticorrosive coatings shows numerous amount of variables that must be explored and controlled looking for, avoiding some of the evident constraints (delamination, cracking, loss of adhesion, uneven distribution, and low mechanical properties) and find new and better answers. Faced with these challenges, there are numerous opportunities regarding factors such as the protective mechanism, the composition of the layers (other precursors and dopants or additives), nature of the organic-inorganic interaction, pH of the reaction, the molar ratio of the precursors, aging time, curing temperature, residual stresses on the substrate surface, coating methods, and testing procedures included long-term behavior.
In conclusion, we can say that a new field of research and business is fully open, with great potential as an anticorrosive coating in agreement with the expectations of the post-globalization time: highly effective, of low cost, environmentally friendly, and easy maintenance. Marked will continue like a snowball thanks to the R&D efforts developed, but with the conviction that they will pay. Corrosionists are invited to take part in this new and profitable business.
Remember: Protection of materials and equipment is a profitable business!
Prof. Carlos Arroyave, Ph.D. Editor.
Materials Biz News
IntechOpen, the world’s leading publisher of Open Access books based in London, calls for chapter contributions to the forthcoming book entitled: “Hydrogels - From Tradition to Innovative Platforms with Multiple Applications.” Corrosionists developing R&D concerning such coatings as an alternative to conventional, toxic and expensive ones, like chromates and phosphates, are specially invited to submit and show another facet of the hydrogel coatings applications, as extended to other fields.
● Chapter proposal submission: 21.10.2021
● Full chapter submission: 20.12.2021
● Full chapter review results: 18.02.2022
● Expected book publication date: 09.05.2021
Further information: Ms. Jelena Vrdoljak, Author Service Manager: [email protected]
This is a focus Issue on characterization of corrosion processes, related with the “Fifth Symposium on High Resolution Characterization of Corrosion Processes: In Honor of Philippe Marcus celebrated in the frame of PRiME 2020, the joint international 2020 fall meeting of The Electrochemical Society of Japan (ECSJ), The Korean Electrochemical Society (KECS), and The Electrochemical Society (ECS). The issue includes 36 papers concerning novel applications of techniques for diving deeper into the understanding of electrochemical corrosion reactions. All the papers are open access.
DeepMC works by training an AI to pinpoint the error between local weather forecast and microclimate weather conditions. The system uses both weather forecasts and historical data from local sensor data for training and predicts each weather parameter separately, such as temperature and wind speed. Researchers examined four real-world uses of DeepMC: wind speed, solar radiation, soil moisture content, and temperature predictions. In all cases, the prediction outperformed comparable models. It is expected that DeepMC will be valid for farmers generating renewable energy and developing their microgrids. Here, we are talking about an innovation useful for corrosion studies concerning atmospheric effects.
These are some of the large O&G companies that are relocating their facilities in the country located at the edge of South America. ExxonMobil Guyana said in an event update Thursday that all its major international contractors have a presence in the new oil-producing country and are “regularly shifting their operations from Trinidad and Tobago and other parts of the world to Guyana.” Local manpower was provided through a joint venture between Guyana Oil and Gas Support Services and the Trinidad Offshore Fabricators Corporation.
Networking & Knowledge Exchange
IFINKOR, the Institute for Maintenance and Corrosion Protection Technology GmbH, at the South Westphalia University of Applied Sciences, Iserlohn, Germany, and the German Society for Corrosion Protection (GfKORR – Gesellschaft für Korrosionsschutz e.V.) are announcing this intensive educational event. The course summarizes the present-day knowledge, in theory, testing, and application of corrosion and scale inhibitors. The emphasis is on the application in selected technical fields and discussion of environmental aspects. As a special course topic, the registration of inhibitor chemicals within the European REACH regulation (Registration, Evaluation, Authorization, and Restriction of Chemicals) will be explained, and the question will be discussed which chemicals will remain in the future in the list of environmentally accepted substances and what strategies are available to select alternatives for presently still needed, however, environmentally less-friendly inhibitor compounds. In this context, the hype for “green inhibitors” based on natural products will be discussed critically. Overall, the aim of the course is to provide enough information to enable course participants to tackle inhibitor problems efficiently.
Dates: Tuesday and Wednesday, November 9th and 10th of 2021
Hours: From 8:30 to 17:00 (GMT + 2)
TWI global offers a webinar designed to show the project FORGE set to develop novel coatings of compositionally complex alloys and ceramics, combining machine learning models, thermodynamic calculations, and high-throughput experiments. This project will demonstrate these coatings on components for industrial processes in Steelmaking, Aluminum, Tiles, and Cement industries, such components for CO2-capture, waste heat recovery, etc.
Date: Thursday, October 14th of 2021
Hours: From 13:00 to 15:00 BST (GMT + 1)
Alternative Fuels Conference 2021. Virtual
Hopin Events offers a conference to debate the future of shipping and join us at this year’s alternative fuels with networking opportunities, panel discussions, and presentations from leading industry players and DNV experts. This year’s event breaks down what you need to know about alternative and emerging fuels.
Date: Wednesday, October 20th of 2021
Hours: From 5:30 to 9:30 (GMT - 5)
Corrosion Tech Week. Hybrid
NACE is offering a four-day ‘’work week’’ event, including a series of meetings focused on methods of identifying, preventing, and combating corrosion problems across all major industries. These meetings also provide a forum for sharing information and solutions to corrosion challenges encountered around the world.
Venue: Royal Sonesta Houston Galleria, Houston, USA
Dates: FromSunday, October 17th to Wednesday, October 20th of 2021
Hours: From 8:00 to 17:00 (GMT - 5)
October 12th East Asia Pacific Area (EAPA) 2021 Conference (Link)
October 14th Waste utilization and symbiosis – Defining the foundation industries’ sector innovation needs (Link)
October 14th How to forge a new class of coatings** (Link)**
October 17th Corrosion Tech Week (Link)
October 20th Alternative Fuels Conference 2021** (Link)**
October 21st Heat recovery and utilization – Solutions for the foundation industries sector (Link)
October 25th Strategic management of maintenance (Link)
October 25th Control Valves & Actuated On/Off Valves (Link)
October 25th Corrosion Modeling Basics (Link)
October 26th 240th Meeting of the Electrochemical Society. (Link)
October 26th Anti-Corrosion Paint Inspection Fundamentals. (Link)
October 28th Sensors, controls, and digitalization – Solutions for the foundation industries sector (Link)
November 9th Corrosion and Scale Inhibition, Theory, Testing, Application (Link)