Enara Mardaras: “We cannot avoid corrosion, but we can reduce its impact acting directly over the materials”

Corrosion is a natural and unavoidable phenomenon which has a significant impact on people, environment and economy. The direct costs associated to corrosion for the Basque Industry are estimated to reach up 3.5% of the GDP. Enara Mardaras, head of Metallic Materials Corrosion and Protection research line at AZTERLAN tells us more about the main aspects that concern the industry regarding corrosion and the working lines of AZTERLAN Metallurgy Research Centre in this field.

Enara Mardaras, coordinator of research line Corrosion and Protection of Materials.

Without any doubt corrosion has a significant impact on the industry. Is it possible to quantify its cost?

Yes and no, as an answer to this complex question. On one hand, it is relatively simple to quantify the direct costs associated to corrosion by the protection and/or substitution of components and equipment. For the Basque metal mechanical industry we estimate that the costs associated to corrosion rise up to 3.5% of the GDP. Nevertheless, no quantified indirect costs should be added to this figure. For instance, costs related to product contaminations or to technical stops for the recovery of the product. As noted in the HOAR Report published by the British Committee for Corrosion Protection, a world-level reference of indirect costs range between 10-15% of the direct costs.

Which are the main challenges of the industry regarding corrosion?

To understand industrial challenges in this field, first, it must be understood that corrosion is a natural and unavoidable phenomenon resulting from the chemical or electro-chemical iteration of materials and environment. This iteration affects the properties and the functionality of components, equipment and structures. Corrosion produces a damage that can end in a critical failure. Such failure can be translated into an economic loss, into a delay in product delivery or in the most extreme cases, it can put in danger human lives. Nevertheless, it is estimated that 20-25% of the economic costs associated to corrosion could be avoided by just applying knowledge that already exists regarding corrosion and protection of materials.

Therefore, I think that the main challenge is to be able to incorporate existing knowledge and, at the same time, to develop new mechanisms and technologies that allow to create safer and longer lasting products that also ensure the economic and environmental sustainability of the process. In this sense, technology centres play a determining role.

It is necessary to inform and educate professionals working in the field of materials, people in charge for the industrial and process performances and the own public administrations on the devastation caused by corrosion phenomena. The most positive step to fight corrosion and degradation of materials begins by admitting the importance of the problem and being able to identify and control its manifestations.

Which kind of solutions do companies demand for fighting corrosion?

The needs of companies are very diverse and depend a lot on the sector they belong to and on the requirements associated to their products and manufacturing process. We work mainly with metal-transforming companies, such as foundries, forges, stamping companies, equipment manufacturers ….., which at the same time serve to different sectors such as automotive, air&space, energy, construction, Oil&Gas, where quality and security standards are very high.

Overall, companies ask for solutions that allow to manufacture safer and more durable components and that assure the profitability of their processes and their products.

The most usual solution to fight corrosion is the application of coatings; but these make processes to be more complex and more expensive. The increase of security factors is also a common practise, which normally implies adding more material than needed, among other disadvantages.

Among the most usual demands we receive from the industry we can point out: optimisation of the design of components for specific mechanical loads and/or environments, improvement of the production process (chemical composition, heat treatments, joint technologies), application of appropriate surface treatments, development of new materials with advanced properties (for instance, for working in high temperatures) or development of innovative treatments that provide specific properties to materials and components.

To prevent corrosion it is necessary to act during the design phase. A preliminary study must be carried out to analyse the factors the materials are going to be exposed to, the conditions of the medium (chemical composition, temperature), any some other relevant physical aspects (efforts, welding, use) along with the prevention methods applicable in each case. Regarding the results of this study, the optimal material and preventative method will be selected, always having into account the economic factor.

Which research lines is AZTERLAN currently working on in the field of corrosion?

Even though we have taken part in projects for the development of advanced anti-corrosion coatings, our main approach is to fight this phenomenon by obtaining improved properties in the base metallic materials. In that sense we try to focus on the metallurgy of the base materials, trying to avoid additional products/processes in order to obtain leaner and more cost-effective manufacturing methods.

Our research lines in the field of corrosion are mainly focused in the following fields: surface modification where molten surfaces (in ferrous and non-ferrous alloys) allow us increase the resistance to aggressive conditions of the medium; the creation of protective surfaces by valorising passive layers (for example the oxide layer naturally given on steels behaves as a protective coating); the development of new alloys with an elemental composition that improves their resistance to specific types of corrosion; and the use of mixed melting techniques to obtain multi-metallic components more resistant to corrosive environments.

On the one hand, we work as well to enhance the properties of already existing materials depending on their application. We also develop new materials to face extreme conditions.