The present thesis work is part of the European research project call: “Environmentally acceptable Pretreatment System for Painting Multi Metals”, with the acronym name of “ENABLE” and type of funding scheme: FP7-SME-2010-1. In which Politecnico di Milano is taking part in alliance with Swerea IVF AB and Volvo Personvagnar Surface Treatment Center. From a production development point of view there is a need for accelerated corrosion methods in order to obtain fast results of the performance of new concepts in pre treatment or paint development. Ideally, accelerated corrosion tests would provide data that could be correlated to actual in-service performance. However, by the very nature of accelerated corrosion tests, these procedures can rarely (if ever) be used to confidently predict service life. In general, actual corrosive environments are more complex and less carefully controlled than accelerated laboratory tests. Therefore, at best, the latter can be used to measure the relative field performance in terms of a particular corrosion mechanism/mode, what during the period of research of this thesis were asses by different tests of the Electrochemical kind, that include Potentiodynamic, Cyclic Voltammetry, Galvanostatic pulse and Electrochemical Impedance Spectroscopy tests. Therefore the problem that the project addresses is to replace the “standard” pre-treatment process for out-door use, zinc phosphating with a new process, since the knowledge concerning the corrosion performance of paint system in CRS (Cold rolled steel) and HDG (Hot deep galvanized steel) based on new pretreatments such as TecTalis and Oxsilan is limited. There is however, a great need for further testing in order to establish an accelerated corrosion test that is known to correlate with field testing for the new pre treatment systems. The corrosion protection properties and correlation to process conditions have to be understood in order to be able to improve the corrosion inhibition properties.
Il presente lavoro di tesi si colloca all’interno di un progetto di ricerca europeo denominato: “Environmentally acceptable Pretreatment System for Painting Multi Metals, con l’acronimo di “ENABLE”. Oltre al Dipartimento di Chimica del Politecnico di Milano, gli altri partner di questo progetto sono Swerea IVF e Volvo Personvagnar Surface Treatment Center. Dal punto di vista dello sviluppo della produzione, esiste la necessità di mettere a punto metodi di corrosione accelerati per ottenere risultati in tempi rapidi circa il comportamento di nuove tecniche di pretrattamento pre verniciatura nel settore automotive. Idealmente infatti i test di corrosione accelerata restituiscono dei risultati che possono essere correlati al comportamento dei componenti trattati in condizioni di reale utilizzo. Tuttavia, per la natura stessa dei test di corrosione accelerata, questo tipo di procedura può essere di rado utilizzata per predire in maniera certa il comportamento in esercizio. In generale infatti gli ambienti atmosferici sono molto più complessi e meno controllati rispetto alle condizioni utilizzate in laboratorio. Di conseguenza, il metodo dei test accelerati può essere utilizzato per conoscere in prima istanza il meccanismo di corrosione. A questo scopo durante il periodo di ricerca di questo lavoro di tesi sono stati svolti diversi tipi di test elettrochimici che includono prove potenziodinamiche, voltammetrie cicliche, impulso galvanostatico ed impedenza. Lo scopo che l’intero progetto di ricerca si pone è quello di sostituire il processo di pretrattamento standard per usi esterni, fosfatazione allo zinco, con nuovi processi quali TecTalis e Oxsilan. L’analisi viene svolta utilizzando due differenti substrati di acciaio, CRS (Cold Rolled Steel) e HDG (Hot Dipped Galvanized Steel), sui quali dopo aver applicato i diversi tipi di coating è stata stesa una vernice. Tuttavia sarà necessario continuare con altre prove con lo scopo di stabilire una modalità di test di corrosione accelerata in grado di descrivere i prossimi risultati del comportamento di esercizio dei nuovi sistemi di pretrattamento.
Electrochemical assessment of innovative pretreatments for automotive painting on HDG and CRS
BRIOSCHI, RENATO;GUTIÉRREZ ZALDÍVAR, RENATA ALIDA
2010/2011
Abstract
The present thesis work is part of the European research project call: “Environmentally acceptable Pretreatment System for Painting Multi Metals”, with the acronym name of “ENABLE” and type of funding scheme: FP7-SME-2010-1. In which Politecnico di Milano is taking part in alliance with Swerea IVF AB and Volvo Personvagnar Surface Treatment Center. From a production development point of view there is a need for accelerated corrosion methods in order to obtain fast results of the performance of new concepts in pre treatment or paint development. Ideally, accelerated corrosion tests would provide data that could be correlated to actual in-service performance. However, by the very nature of accelerated corrosion tests, these procedures can rarely (if ever) be used to confidently predict service life. In general, actual corrosive environments are more complex and less carefully controlled than accelerated laboratory tests. Therefore, at best, the latter can be used to measure the relative field performance in terms of a particular corrosion mechanism/mode, what during the period of research of this thesis were asses by different tests of the Electrochemical kind, that include Potentiodynamic, Cyclic Voltammetry, Galvanostatic pulse and Electrochemical Impedance Spectroscopy tests. Therefore the problem that the project addresses is to replace the “standard” pre-treatment process for out-door use, zinc phosphating with a new process, since the knowledge concerning the corrosion performance of paint system in CRS (Cold rolled steel) and HDG (Hot deep galvanized steel) based on new pretreatments such as TecTalis and Oxsilan is limited. There is however, a great need for further testing in order to establish an accelerated corrosion test that is known to correlate with field testing for the new pre treatment systems. The corrosion protection properties and correlation to process conditions have to be understood in order to be able to improve the corrosion inhibition properties.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/21132