Alec Groysman: Reflection about Azure Window, Part 2, "Corrosion, Architecture and Music"

ALEC GROYSMAN, PhD, DOCTOR OF CHEMISTRY

THE CHAIRMAN OF THE ISRAELI SOCIETY OF CHEMICAL ENGINEERS AND CHEMISTS, TECHNION, ISRAEL INSTITUTE OF TECHNOLOGY, HAIFA, ISRAEL

Сopyright © Svetozar Andreev, 2018. All rights reserved

Corrosion, Architecture and Music

I have been dealing for 40 years with the subject of corrosion of materials and their selection for various conditions with great pleasure. I always like to start with definitions. Corrosion is the interaction of materials (usually metals) with the environment, leading to the deterioration of the functional properties of metals and the state of the environment.

Today, probably, there are no people who in one or another way would not be faced corrosion at home, at the neighbors or at work. Architects should constantly deal with the selection of materials, their properties and behavior, prevention of destruction, and their durability. Therefore, knowledge of the basics of corrosion is an important aspect of their professional life. I constantly follow the use of metals in architecture, as this is a part of my corrosion course, which I deliver in different countries.

Several days ago, quite by chance, I got acquainted with the project of the architect Svetozar Andreev from St. Petersburg, Russia. He proposed to restore the “Azure Window” in Malta, have been destroying by the waves of the Mediterranean Sea two years ago, from metal and composite materials, and thus to complete the disturbed natural ensemble. It intrigued me, and I wanted to find out which metal was talked about. I found quickly the address of Svetozar, who wrote to me that it’s about stainless steel or titanium.

About 10 years ago, I wrote the book “Corrosion for Everybody”, published by Springer. And then two more books about the durability of materials, the reasons for their destruction, and how to increase their service life came to life. I write in these books about the experience of using stainless steels and titanium, corrosion problems and their solutions.

The rich experience of the application of both alloys has accumulated in architecture and in constructions. The Chrysler Building of 77 floors in New York was built from austenitic stainless steel in 1928-1930. The Guggenheim Museum in Bilbao, Spain, was made from titanium in the late 20th century. People enjoy observing the beauty of these buildings.

What about the water of the Mediterranean Sea? There is much less data. Titanium can be used in seawater. What about stainless steels? There are almost 300 species of stainless steels. They all differ in structure, chemical composition, mechanical properties, resistance to seawater and the atmosphere, microorganisms, and erosion. What is dangerous in using stainless steel in seawater? The factors determining the stability of these steels in water are: the chemical composition of the medium, the flow rate (oh, these waves!), temperature, oxygen concentration, the presence of microorganisms, and contact with other materials.

Firstly, stainless steel in the “Azure Window” will be in contact with four different environments: underwater soil, seawater, the water-atmosphere interface, and the sea atmosphere. Secondly, there are chlorides in all these environments - anions that cause pitting and crevice corrosion. In addition, it is necessary to consider other possible forms of corrosion: chloride stress corrosion cracking, microbiological corrosion, erosion, and galvanic corrosion. For stainless steels, an important element of their effective performance and durability is final surface preparation and passivation. Nowadays, there are technologies of applying nano-coatings onto the stainless steel surface to increase their resistance to the harsh environment. Unfortunately, the data about the resistance of stainless steels in seawater in the literature are controversial. My personal experience with stainless steels and new data suggest that austenitic steels with a molybdenum content of more than 4-6% and Duplex steels can be used to implement the “Heart of Malta” project. Of course, some additional research is needed. Then we will be able to realize the connection and interaction between different arts and to turn the “frozen music” of architecture into a Grand Cultural Center that attracts people of different interests and ages. This project will be the pride of the country of Malta, its attraction, the only in the world, and will mesmerize not only Maltese, but also tourists from other countries. And I will definitely be among them.