Conversion coating distribution on rough substrates analyzed by combining surface analytical techniques

Detection and quantification of defect evolution at buried metal-oxide-polymer interface on rough substrate by local electrochemical impedance mapping

“…The take-off angle of the analyzed Auger electrons was below 30° from the primary electron beam, which minimized the shadowing effect. As in [44], the results demonstrated homogeneous erosion inside GD OES craters and shadowing effects existed in the craters formed by ToF SIMS sputtering. The latter can lead to the "effective" area which is smaller than targeted zone in case of the defects produced by ToF SIMS.…”

“…The sputtering parameters were chosen in a way that for both types of generated craters the conversion layer was thinned but still present all over the crater area and was not chemically modified. The procedure is described in detail in [44].…”

“…The sputtering time necessary to reach the interface, ts, was thus detected for each batch and the craters were generated using the sputtering time of 0.8´ts. It was assumed that 80 % of the initial thickness is eroded in such a procedure (see [44] for details).…”

“…The homogeneity of the oxide thickness distribution in the sputtered craters was in detail characterized using the methodology described in [44]. The thickness variation between different locations on the same sample was not more than 30 %.…”

“…The main objective of the present work is to propose a methodology for such an evaluation for electrodeposited Zn-alloy substrate with a Cr(III) conversion coating and an epoxy polymer paint. The proposed approach is based on the interplay of the concepts developed in our previous works, namely: 1) a quantitative description of the deadhesion (delamination) advancement from a defect in the polymer coating at metal-polymer interface using LEIM [36] 2) an application of a model epoxy -based coating which allows LEIM measurements underneath without a preliminary defect formation and helps to mimic the behavior of buried interface and distinguish conversion coating with and without defects [41] 3) a methodology able to produce a controlled local nanometer thinning of conversion coating without affecting the roughness of the substrate [44].…”