Determination of coating performance with impedance measurements

Mechanical Maritime and Materials Engineerin

SPR voor uniform gekleurde lagen

Er zijn verschiUende manleren om oppervlakken te bewerken zoals anodiseren, poedercoaten, lakken, verzinken, galvaniseren, spulten en moffelen, en emailleren. Materials Innovation Institute (M21) heeft in het kader van het innovatieprogramma High Tech Materials aangetoond dat het mogelijk is om Lagen met uniforme held ere kleuren te creeren door toepassing van geLokaliseerde Surface Plasmon Resonance (SPR) in de aangebrachte laag. SPR is een techniek waarbij kleine veranderingen in de brekingsindex boven een oppervlak worden gemeten

SPR voor uniform gekleurde lagen

Er zijn verschiUende manleren om oppervlakken te bewerken zoals anodiseren, poedercoaten, lakken, verzinken, galvaniseren, spulten en moffelen, en emailleren. Materials Innovation Institute (M21) heeft in het kader van het innovatieprogramma High Tech Materials aangetoond dat het mogelijk is om Lagen met uniforme held ere kleuren te creeren door toepassing van geLokaliseerde Surface Plasmon Resonance (SPR) in de aangebrachte laag. SPR is een techniek waarbij kleine veranderingen in de brekingsindex boven een oppervlak worden gemeten

Application of impedance spectroscopy during the lifetime of organic coatings

In this paper the use of Electrochemical Impedance Spectroscopy is evaluated for three situations during the lifetime of organic barrier coating. These situations are: • Defect free coatings • Delaminated, but intact coatings • Coatings with defects combined with cathodic delamination It is shown that in the first case EIS is reduced to a dielectric study of the coating polymer. This study gives information on the technical lifetime of an intact coating. In the second case only a qualitative indication of the onset of delamination can be obtained. In the last case contributions of the pore and the corrosion product within the pore are measured. It is not possible to measure a delaminated area

The use of electrochemical measurement techniques towards quality control and optimisation of corrosion properties of thermal spray coatings

Metal spray coatings are ever more recognised as a possible superior means of corrosion protection in many environments. Extended service life combined with little or no maintenance provides interesting opportunities for both environmentalists and corrosion engineers. Although many successful applications of corrosion protection using thermal spray coatings have been reported, both in atmosphere as in immersion service, new applications remain limited. The complexity of the coating buildup and the number of parameters that may greatly affect the resulting corrosion protection continues to confuse possible users. An important instrument to support the selection of thermal spray coatings is the development and implementation of a reliable quality control procedure. Particularly, concerning the corrosion protection behaviour, the use of both traditional and modem electrochemical tools can provide important information in this respect. Moreover, the mechanistic information resulting from electrochemical tests can not only be used for quality testing purposes but may also be used to optimise the application parameters of the thermal spray coating to achieve the best possible corrosion protection in a specific environment. This paper describes the use of various electrochemical measurement methods to determine the electrochemical characteristics of stainless steel AISI 316, aluminium and Monel 400 thermal spray coatings in aqueous environments. An evaluation will be made of the applicability of the technique and the interpretation of the obtained results towards thermal spray application parameters

Quantification of coating aging using impedance measurements

This chapter shows the application results of a novel approach to quantify the ageing of organic coatings using impedance measurements. The ageing quantification is based on the typical impedance behaviour of barrier coatings in immersion. This immersion behaviour is used to determine the limiting case for the interpretation of results on coatings exposed to artificial and outdoor weathering

Dielectric properties reflecting coating performance

The use of Electrochemical Impedance Spectroscopy (EIS) in coatings research is widespread. The information obtained by this technique is often limited, which is the result of too high expectations and inadequate analysis and interpretation. Analysis of the dielectric properties of organic coatings using a Constant Phase Element (CPE) in the equivalent circuit reveals detailed information on coating properties as curing stage, water uptake and electrolyte sensitivity, swelling and onset of delamination, but also on the weathering of the coating. The determination of weathering using EIS is developed further and a quantitative parameter the Weathering Index W is introduced. Examples of results on coatings exposed to several types of accelerated weathering are given