Novel insight to aluminum compounds in the outermost layers of hot dip galvanized steel and how they affect the reactivity of the zinc surface

Saarimaa, Ville; Markkula, Antti; Juhanoja, Jyrki; Skrifvars, Bengt-Johan

doi:10.1016/j.surfcoat.2015.11.014

Cited by 13 publications

(16 citation statements)

References 30 publications

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“…The aluminum depth profile obtained by GD-OES for each time and for a solvent cleaned sample is represented in Figure 4. As shown in Figure 4, for the solvent cleaned sample, an aluminum enrichment of the first nm (~100 nm) is present and agrees with the literature [1][2][3][4][5][6][7][8][9]. After alkaline cleaning, the content of aluminum dropped, and the bulk value was reached after 300 nm.…”

Section: Study Of the Impact Of The Time Of Alkaline Cleaningsupporting

confidence: 89%

“…Due to a small addition of aluminum (0.1-0.3 wt%) in the galvanizing bath, to its limited solubility in zinc matrix, and to its affinity to oxygen, the surface of hot-dip galvanized steel (HDG) is enriched in aluminum. An atomic concentration ratio of Al to Zn of about 1-3:1 for the uppermost 30 Å was observed by Feliu et al [1] on HDG and Galfan (Zn-5Al) surfaces and the presence of a thin film of aluminum oxide at the extreme surface is now well accepted and documented [1][2][3][4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 78%

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Multiscale and Multi-Technical Approach to Characterize the Hot-Dip Galvanized Steel Surface and Its Consequence(s) on Paint Adhesion and Tendency to Blistering

Pélissier

Thierry

2021

Coatings

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It is well known that the surface state (cleanliness, composition) of galvanized steel prior to the application of an organic coating is an important parameter. The surface state will affect the adhesion properties of the complete system and therefore will also impact its corrosion resistance and its tendency to blistering. Before the application of a pretreatment layer, galvanized steel strips are normally alkaline cleaned. This step is known to remove the native oxide film formed on hot dip galvanized steel after processing and appears as one of the most important steps to study the impact of the surface properties on the performance of painted systems. This study focused on making use of the cleaning step to input a variability on the surface composition (mainly surface concentration of aluminum) and evaluate its consequence(s) on the performance of a complete paint system. The results showed that, a variability in terms of surface aluminum concentration could be achieved by the cleaning step and that signs of performance improvement in terms of adhesion and tendency to blistering were spotted with a low content of aluminum at the surface.

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Section: Study Of the Impact Of The Time Of Alkaline Cleaningsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 78%

Multiscale and Multi-Technical Approach to Characterize the Hot-Dip Galvanized Steel Surface and Its Consequence(s) on Paint Adhesion and Tendency to Blistering

Pélissier

Thierry

2021

Coatings

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“…On the surface of non-etched HDG surface, over 30% of the atoms detected in the outermost few nanometers were aluminum. The rest was mostly oxygen with small contributions from zinc and carbon [20]. The surface aluminum concentration decreased when the sample was treated in an alkaline solution.…”

Section: Alkaline Cleaningmentioning

confidence: 99%

Effect of Hot Dip Galvanized Steel Surface Chemistry and Morphology on Titanium Hexafluoride Pretreatment

Saarimaa¹,

Markkula²,

Arstila³

et al. 2017

AMPC

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Titanium hexafluoride pretreatments are known to improve paint adhesion and function as a barrier between the coating and the hot dip galvanized (HDG) steel surface. Interactions at the zinc/pretreatment interface are of utmost importance for the formation of pretreatment layers and the corrosion resistance of color coated hot dip galvanized steels. Removal rate of inert aluminum oxide from HDG steel samples by chemical dissolution was studied. XPS measurements showed that the surface Al 2 O 3 layer thickness decreased rapidly already at mild alkaline cleaning, while complete removal of Al required severe etching. Low reactivity of an Al 2 O 3 -rich surface was confirmed by impaired formation of a titanium hexafluoride pretreatment layer. Grain boundaries and deformation twinnings were shown to be of importance for the reactivity of the HDG surface and for the precipitation of the pretreatment chemical. Helium ion microscopy images and electron probe microanalysis (EPMA) of a pretreated sample showed accumulation of the pretreatment chemical at the grain boundaries. Al removal rate was fast at the deformation twinnings at the grain plateaus. Slow Al removal was observed at dendritic valleys and grain boundaries. The results increase understanding of the reactivity of hot dip galvanized steel surface.

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“…The surface of the steel wire was galvanized. The zinc coating is prone to oxidation reactions when it is exposed to air 26 , 27 . Therefore, the outermost layer of the steel wire rope is ZnO.…”

Section: Resultsmentioning

confidence: 99%

Application of a water jet for cleaning grease and improving the surface adhesion properties of galvanized steel wire ropes

Miao

Zhang²,

et al. 2022

Sci Rep

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Traditional cleaning processes may be banned in the near future because of the hazards they pose to the environment. In this study, a water jet was used to clean grease residues from steel wires for the first time. The EDS and SEM results of the steel wire rope surfaces and supplementary water jet impact experiments on galvanized steel plates revealed that when the pressure was lower than 50 MPa and the traverse speed was higher than 600 mm/min, the water jet caused minimal damage to the coating. When the pressure was 5 MPa, the cleaning ratio was between 45 and 60%, and the level of cleaning increased with increasing pressure. Two proposed concepts of exposure ratio and nonexposed area were applied to quantitatively analyze the theoretical upper and lower limits for grease that could be cleaned from two typical structures. The results showed that the lower and upper cleaning limits for structure 7 × 3 were 38.1% and 83.3%, while the lower and upper limits for structure 1 × 3 + 5 × 7 were 35.5% and 59.2%, respectively. This result explains why the grease content of structure 7 × 3 was lower than that of structure 1 × 3 + 5 × 7 after cleaning. In addition, the adhesion test results showed that adhesion to the two kinds of steel wire ropes after cleaning was increased by 126% and 145.71%, respectively, which means that additional processes for improving adhesion could be omitted after using a water jet for cleaning. This is an advantage that traditional cleaning processes do not offer.

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Novel insight to aluminum compounds in the outermost layers of hot dip galvanized steel and how they affect the reactivity of the zinc surface

Cited by 13 publications

References 30 publications

Multiscale and Multi-Technical Approach to Characterize the Hot-Dip Galvanized Steel Surface and Its Consequence(s) on Paint Adhesion and Tendency to Blistering

Multiscale and Multi-Technical Approach to Characterize the Hot-Dip Galvanized Steel Surface and Its Consequence(s) on Paint Adhesion and Tendency to Blistering

Effect of Hot Dip Galvanized Steel Surface Chemistry and Morphology on Titanium Hexafluoride Pretreatment

Application of a water jet for cleaning grease and improving the surface adhesion properties of galvanized steel wire ropes

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