Convenient extraction method for quantification of thin zinc patina layers

Abstract

Synthetic zinc patina was grown on galvanized steel sheets in supercritical carbon dioxide atmosphere. Different patina compounds were dissolved and quantified using a stepwise immersion and dissolution procedure. The distinct patina components, namely anhydrous zinc carbonate (a dense layer adjacent to metallic zinc) and zinc hydroxy carbonate (nanowires on the surface), were dissolved in glycine solutions, followed by quantification of Zn 2+ in the solutes by X-ray fluorescence. The zinc hydroxy carbonate nanowires were readily glycine soluble, and the anhydrous zinc carbonate showed scarce glycine solubility, which enabled their selective quantification. The amount of the remaining (anhydrous) zinc carbonate after glycine extraction was determined from the glycine-soluble zinc oxide after calcination (heat treatment for 10 minutes at 350°C). The results were verified by scanning electron microscopy imaging and Fourier transform infrared spectroscopy measurements.

Simulated rain exposures can mimic long‐term metal runoff at atmospheric conditions—A case study on naturally and prepatinated zinc sheet

“…According to the literature, the P.Patina (P.Patina‐1 and P.Patina‐2) consist of an inner layer of ZnCO 3 and ZnO, with nanowires of zinc hydroxy carbonate (Zn x (CO 3 ) y (OH) z ) in a flower‐like appearance on P.Patina‐2. [ 21 ] This was confirmed by XRD identifying both ZnO (JCPDS: 36‐1451) and ZnCO 3 (JCPDS: 8‐449) as crystalline corrosion products on both unexposed and laboratory‐exposed P.Patina‐1 surfaces whereas P.Patina‐2, in addition, displayed the main diffraction peak(s) of Zn 5 (CO 3 ) 2 (OH) 6 (JCPDS: 19‐1458) for all samples, Figure 5. FTIR indicated the presence of both ZnCO 3 and Zn 5 (CO 3 ) 2 (OH) 6 , possibly in different proportions and degrees of crystallinity, to be the major components of the patina, in particular on all surfaces as exemplified in Figure 5 (XRD) and Figure 6 (FTIR).…”

Tailoring of Versatile Surface Morphologies on Hot Dip Galvanized Steel in Wet CO2: Aspects on Formation, Barrier Properties, and Utilization as a Substrate for Coatings

“…7 Furthermore, the zinc carbonation products can be converted to zinc oxide by thermal treatment, which opens a wide range of future applications for materials produced via scCO 2 synthesis. 9,10 The reactions of different metals and minerals in wet scCO 2 are not yet thoroughly understood, but tentative reaction sequences can be constructed with the available studies. First, although CO 2 is a corrosive gas, synthesis of Zn nanostructures is very limited in dry scCO 2 .…”

“…Wet supercritical carbon dioxide (scCO 2 ) treatment has been proposed as a medium for zinc carbonate (or oxide) nanowire synthesis. , CO 2 is abundantly available and cost efficient, and the synthesis can be carried out in a single process step . Furthermore, the zinc carbonation products can be converted to zinc oxide by thermal treatment, which opens a wide range of future applications for materials produced via scCO 2 synthesis. , …”

Synthesis of ZnO nanowires with supercritical carbon dioxide and post heat treatment

“…Moreover, we presented that the process could be enhanced by the addition of a catalyst to increase the surface coverage of the nanowires on zinc. We also proposed that this method could be used as a pretreatment for galvanized surfaces to promote adhesion before coating [19,20].…”