1. 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 UNIVERSITÀ POLITECNICA DELLE MARCHE Dipartimento di Scienze e Ingegneria della Materia, dellAmbiente ed Urbanistica Facoltà di Ingegneria, ANCONA (ITALY)

2. 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) THE CORROSION PHENOMENON

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

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

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

6. Corrosion has a huge economic and environmental impact on virtually all facets of the worlds infrastructure, from highways, bridges, and buildings to oil and gas, chemical processing, and water and wastewater systems. World Corrosion Organization (2009) THE CORROSION IMPACT ON ECONOMY ANNUAL COST OF CORROSION WORLDWIDE IS ESTIMATED $US 2.2 TRILLION US estimated costs of corrosion (nace.org) InfrastructureB$22.6 UtilitiesB$47.9 TransportationB$29.7 Production & ManufacturingB$17.6 GovernmentB$20.1 TOTALB$137.9

7. Fe(OH) 2 Fe ++ OH - O2O2 O2O2 e - Fe Fe ++ + 2e - anodic reaction cathodic reaction O 2 + 2H 2 O + 4e - 4OH - steel water media 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. INTERNAL SURFACE PASSIVATION OF THE WATER TANKS HF + HNO 3 solution

13. AISI 304L, AISI 316L e AISI 444 chemical composition Pitting Resistance Equivalent PRE = % Cr + 3.3 x %Mo AISI 304L 18.9 AISI 316L24.5 AISI 44424.6 Increasing localized corrosion resistance

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

15. SURFACE ASPECT OF STAINLESS STEEL AFTER PASSIVATION AISI 304LAISI 316LAISI 444 Surface finishing F4 HF 3% HNO 3 13%, r.t., 45 Surface finishing F8 F4 + HNO 3 30%, r.t., 30

16. Perfect passivity region Imperfect passivity region TW1: [Cl - ]=132.8 ppm EXPERIMENTAL RESULTS OBTAINED WITH TW1 F1 F4 HF+HNO 3 F8 HF+HNO 3 HNO 3 T. Bellezze, G. Roventi, A. Quaranta and R. Fratesi, Materials and Corrosion 2008, 59 (9), 727-731

17. INNOVATIVE SURFACE PROTECTION SYSTEMS

18. SURFACE PROTECTION SYSTEMS: ZINC COATINGS ON STEEL cathodic reaction: O 2 +2 H 2 O + 4e - 4OH - e - Zn ++ OH - O2O2 anodic reaction: Zn Zn ++ + 2e- Zn ++ e - steel water media zinc The zinc coating offers: -barrier effect -sealing effect -cathodic protection -recyclability -lower costs with respect to other coating solutions car pylon reinforcing bars

19. DIFFERENT METHODS TO OBTAIN ZINC COATINGS ON STEEL electrochemical depositionhot-dip galvanizing (94% Zn; 6% Fe) (94% Zn; 6% Fe) (100% Zn) (100% Zn) (90% Zn; 10% Fe) (90% Zn; 10% Fe) (75% Zn; 15% Fe) (75% Zn; 15% Fe) 100 m 10 m

20. FURTHER PROTECTION OF ELECTRODEPOSITED ZINC: ZINC COATING PASSIVATION ZINC STEEL CONVERSION LAYER Use of Cr VI containing baths: Cr 2 O 7 2- + 14 H + + 6e - 2Cr 3+ + 7 H 2 O 2H + + 2e - H 2 Zn Zn 2+ STEEL ZINC CONVERSION LAYER local damage self-healing effect chromating

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. 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; … POSSIBLE ALTERNATIVES TO THE USE OF Cr VI

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

24. 2 μm 5 μm OUR WORK ON THE ALTERNATIVES TO THE USE OF Cr VI Cr III conversion layerCr 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 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. pulsed current microhardness EDX map of SiC (about 2%) distribution on zinc coating decorative chromium plating hard chromium plating

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

27. MONITORING REINFORCING CORROSION IN CONCRETE WITH THE RISK OF CARBONATION CO 2 concrete steel bar CO 2 H2OH2O core sampling pH decreases

28. MultiProbe A MultiProbe B CO 2 the cast Inside carbonation chamber MONITORING THE CARBONATION DEPTH Ti ref.

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)