ROUND TABLE RUSSIA ↔ ITALY Chemical Technologies : Perspectives of development June 4th -7th 2012

1. UNIVERSITÀ POLITECNICA DELLE MARCHE Dipartimento di Scienze e Ingegneria della Materia, dell’Ambiente ed Urbanistica Facoltà di Ingegneria, ANCONA (ITALY) Prevention and control of corrosion phenomena directed to extend components and structures durability Dr. Tiziano Bellezze ROUND TABLE RUSSIA ↔ ITALY Chemical Technologies : Perspectives of development June 4th -7th 2012 Ivanovo State University of Chemistry and Technology, Ivanovo, RUSSIA

2. THE CORROSION PHENOMENON “Corrosion has been the subject of scientific study for more than 150 years. It is a naturally occurring phenomenon commonly defined as the deterioration of a material (usually a metal) or its properties because of a reaction with its environment.” World Corrosion Organization (2009)

3. ABOUT THE ENVIRONMENT… (“the enemy”) industrial environment marine environment urban environment

4. ABOUT THE ENVIRONMENT… (impact, preservation…) Accumulation of waste materials automotive scraps appliance scraps Risks of pollution and environmental disasters pipelines failure tank failure

5. CONCERNS WITH HUMAN HELTH AND LIFE Realise of metals produced by corrosion phenomena tap water natural water cooking pot Accidents due to corrosion collapse of ceiling in a swimming pool, Zurich 1985 bridge collapse in Minneapolis on August 1, 2007

6. THE CORROSION IMPACT ON ECONOMY “Corrosion has a huge economic and environmental impact on virtually all facets of the world’s infrastructure, from highways, bridges, and buildings to oil and gas, chemical processing, and water and wastewater systems.” World Corrosion Organization (2009) ANNUAL COST OF CORROSION WORLDWIDE IS ESTIMATED $US 2.2 TRILLION

7. cathodic reaction O2 + 2H2O + 4e- 4OH- water media O2 O2 OH- OH- OH- OH- Fe(OH)2 Fe++ Fe(OH)2 Fe++ steel e- e- e- e- anodic reaction Fe Fe++ + 2e- THE CORROSION OF STEEL

8. STRATEGIES FOR CORROSION PREVENTION AND CONTROL • Materials development and selection • Analysis and optimization of industrial processes • Innovative surface protection systems • Monitoring methods using sensors and remote data collection • Development of electrochemical methods/new analytical methods for studying corrosion phenomena • Education, training courses • ... TO INCREASE STRUCTURES AND COMPONENTS DURABILITY

9. MATERIALS DEVELOPMENT AND SELECTION AND ANALYSIS AND OPTIMIZATION OF INDUSTRIAL PROCESSES

10. SCHEME OF A DOMESTIC BOILER

11. EXAMPLES OF LOCALIZED CORROSION IN STAINLESS STEEL WATER TANKS

12. HF + HNO3 solution INTERNAL SURFACE PASSIVATION OF THE WATER TANKS

13. PRE = % Cr + 3.3 x %Mo Pitting Resistance Equivalent 18.9 AISI 304L 24.5 AISI 316L Increasing localized corrosion resistance 24.6 AISI 444 AISI 304L, AISI 316L e AISI 444 chemical composition

14. AISI 304L AISI 316L AISI 444 SURFACE ASPECT OF STAINLESS STEEL (AS RECEIVED) – F1

15. AISI 304L AISI 316L AISI 444 SURFACE ASPECT OF STAINLESS STEEL AFTER PASSIVATION Surface finishing F4 HF 3% HNO3 13%, r.t., 45’ Surface finishing F8 F4 + HNO3 30%, r.t., 30’

16. HF+HNO3 HNO3 F1 F8 F4 HF+HNO3 Imperfect passivity region Perfect passivity region EXPERIMENTAL RESULTS OBTAINED WITH TW1 TW1: [Cl-]=132.8 ppm T. Bellezze, G. Roventi, A. Quaranta and R. Fratesi, Materials and Corrosion 2008, 59 (9), 727-731

17. INNOVATIVE SURFACE PROTECTION SYSTEMS

18. cathodic reaction: O2 +2 H2O + 4e-  4OH- water media O2 Zn++ Zn ++ zinc OH- OH- steel e- e- e- e- anodic reaction: Zn Zn++ + 2e- SURFACE PROTECTION SYSTEMS: ZINC COATINGS ON STEEL car reinforcing bars pylon • The zinc coating offers: • barrier effect • sealing effect • cathodic protection • recyclability • lower costs with respect to other coating solutions

19. 10 m  (100% Zn)  (94% Zn; 6% Fe) 100 m  (90% Zn; 10% Fe)  (75% Zn; 15% Fe) DIFFERENT METHODS TO OBTAIN ZINC COATINGS ON STEEL electrochemical deposition hot-dip galvanizing

20. self-healing effect local damage ZINC CONVERSION LAYER STEEL FURTHER PROTECTION OF ELECTRODEPOSITED ZINC: ZINC COATING PASSIVATION “chromating” CONVERSION LAYER Use of Cr VI containing baths: Cr2O72- + 14 H+ + 6e- → 2Cr3+ + 7 H2O 2H+ + 2e-→ H2 Zn → Zn2+ ZINC STEEL

21. 1 μm Cr VI CONVERSION LAYER (CHROMATING) Cr VI= • Directive EU End of Life Vehicles 2000/53/EC: • Annex II: Cr VI maximum 2 g per vehicle from 1 July 2003 • Amendment Annex II 2002/525/EC : 0 g from 1 July 2007 for corrosion preventive coatings

22. POSSIBLE ALTERNATIVES TO THE USE OF Cr VI • Other oxidant agents similar to chromates: molybdates, vanadates and permanganetes; • Ce III and Ce IV salts; • Cr III (content of Cr VI reduced more than 100 times) with and without sealants based on Si and some organic compounds (directed to improve the barrier effect); furthermore, after drying, Cr III + sealant conversion coating has the possibility of self-healing effect (migration of silicates present in the sealant); • Organic compounds producing metal-organic films (ex. Si compounds); • … • Use of Cr VI-free conversion layer on zinc alloys (Zn-Ni, Zn-Fe,…) • … • New strategy: nanocontainers for corrosion inhibitors, released “on demand”; • …

23. NANOCONTAINERS FOR CORROSION INHIBITORS M. G. S. Ferreira et. al., Chem. Mater. 2007, 19, 402-411

24. 5 μm 2 μm OUR WORK ON THE ALTERNATIVES TO THE USE OF Cr VI Cr III conversion layer Cr III + sealant conversion layer • Investigations performed using the following techniques: • Electrochemical Impedance Spectroscopy (EIS) in NaCl 5% • Anodic polarization in NaCl 5% • Salt fog spray exposure (ASTM B 117) • Results: the Cr III + sealant conversion layer showed a corrosion resistance comparable with Cr VI conversion layer T. Bellezze, G. Roventi, R. Fratesi , Surface and Coatings Technology 155 (2002) 221–230

25. ALTERNATIVES TO CHROMIUM PLATING • decorative chromium plating • hard chromium plating The Cr electrodeposition is performed by Cr VI containing baths Recently, in our research group, an attempt to substitute the chromium coating with a composite zinc coating containing nanoparticles (60 nm) of SiC was done. This coating is particularly indicated in those applications where high hardness is not necessary. microhardness pulsed current EDX map of SiC (about 2%) distribution on zinc coating

26. MONITORING METHODS USING SENSORS AND NEW APPROCHES IN CORROSION STUDIES

27. MONITORING REINFORCING CORROSION IN CONCRETE WITH THE RISK OF CARBONATION H2O CO2 concrete CO2 steel bar pH decreases core sampling

28. MONITORING THE CARBONATION DEPTH MultiProbe A MultiProbe B Ti ref. CO2 CO2 Inside carbonation chamber the cast

29. MONITORING THE CARBONATION DEPTH WITH MULTIPROBE B

30. MONITORING THE CARBONATION DEPTH multiprobes response vs colourimetric test

31. POSSIBILITY OF MONITORING OTHER CORROSION PARAMETERS • Chlorides penetration depth • Humidity of concrete matrix (as a function of depth) • Corrosion potential • Corrosion rate • Aggressiveness of the concrete matrix • etc. “MULTIPROBES BOX”

32. CONCLUSIONS • Corrosion phenomena have many social, economic and health implications on human life. • For new technological challenges, a cultural training on materials and their degradation is fundamental, both in industrial R&D and in the university research centres. • Efforts on the monitoring strategies and on the development of new devices and/or new sensors should become a standard practice. • At the same time, corrosion experts have concluded that a net of 20 to 25% of that annual cost can be saved by applying currently available corrosion control technologies. (WCO, 2009)