Examination by ESCA of the Constitution and Effects on Lacquer Adhesion of Passivation Films on Tinplate

Servais, J. P.; Lempereur, J.; Renard, Lucien; Leroy, Vincent

doi:10.1179/000705979798275717

Cited by 9 publications

(2 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(17,18). Modification of the hopeite structure is reflected in an increased resistance to alkalinity and a higher dehydration temperature (19). Both of these properties contribute to improved corrosion and adhesion properties of painted steel (qv), zinc, and zinc alloy surfaces (see Zinc and zinc alloys).…”

Section: The Zinc Phosphating Processmentioning

confidence: 99%

Metal Surface Conversion Treatments

Petschel

Hart

2000

Kirk-Othmer Encyclopedia of Chemical Technology

View full text Add to dashboard Cite

Reactive metal surfaces can be chemically treated and covered with inert, amorphous, or crystalline coatings which grow on the base metal. Phosphates represent the most important area of the conversion coatings. These coatings (qv) are applied as preparation for painting, temporary corrosion protection, lubricant carrier in cold forming, friction improver for stamping and drawing, and as insulation on electrical steels (1-3) (see also Metallic coatings; Metal treatments).Phosphating processes began with the work of Thomas Watts Coslett. The original patent covered the use of phosphoric acid to which iron filings had been added (4). It took from 2 to 2.5 hours exposure in boiling solution to form a coating on iron and steel articles. Early improvements consisted of controlling the quantity of free phosphoric acid, thus inhibiting attack on the metal, and of accelerating the reaction by using an electric current. Concentrates from which phosphate baths could be prepared by dilution were in use by 1909. The use of zinc in the phosphate bath was patented in 1909 and the use of manganese in 1911 (5). The use of manganese dihydrogen phosphate gave rise to the process which became known as Parkerizing. Reduction in processing time from one hour to 10 minutes came through the addition of copper to the bath. This was the basis for the Bonderizing process. Addition of an oxidizing agent such as nitrate increased the reaction rate by preventing the adsorption of hydrogen on the metal surface. Paint-base phosphate coatings could be applied in two to five minutes. In 1934, this time constraint was shortened even further when phosphate solutions were sprayed onto the metal surface. Processing times as short as 60 seconds became possible.A crucial development for zinc phosphate coatings came in 1943 when it was found that more uniform and finer crystals would develop if the surface was first treated with a titanium-containing solution of disodium phosphate (6). This method of crystal modification is a prime reason for the excellent paint (qv) adhesion seen on painted metal articles.Modern phosphating practice involves the treatment of reactive metals with acidic phosphate-containing solutions. This produces a coating which consists mainly of phosphate compounds. Chemically, phosphating processes can be separated into two types. In processes of the first type, the metal ions of the phosphate layer derive almost totally from the substrate. These layers, known as noncoating or iron phosphates, are based on sodium and ammonium dihydrogen phosphate. Processes of the second type, on the other hand, provide metal ions for coating either partially or totally in the phosphate bath. These are the zinc phosphate processes which may contain zinc alone or modifying ions such as nickel, manganese, calcium, as well as several others.

show abstract

Section: The Zinc Phosphating Processmentioning

confidence: 99%

Metal Surface Conversion Treatments

Petschel

Hart

2000

Kirk-Othmer Encyclopedia of Chemical Technology

View full text Add to dashboard Cite

show abstract

“…Although this equation provided a reasonable fit, given the sample variation and measurement technology of the time, it ignores the role of the Sn and SnOx and other surface species on adhesive failure. Other literature has identified two adhesion failure mechanisms in the lacquer/tinplate system: failure induced by contamination between tinplate passivation and lacquer and detachment of the tin oxide film.…”

Section: Introductionmentioning

confidence: 99%

Identifying interlayer surface adhesion failure mechanisms in tinplate packaging steels

et al. 2019

View full text Add to dashboard Cite

Tinplate surface morphology and chemistry is adjusted during the manufacturing process in order to meet the demands of its subsequent product use, the commonest being visual appearance and food packaging stability. A comprehensive experimental study on an industrial tinning line varied the surface roughness and the tin coating weight with the characterization through X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), white light interferometer (WLI), optical imaging, and lacquer adhesion measurement. Increasing tin weight lowers the adhesion through the production of a thicker disorganized tin oxide layer which has a greater tendency to fracture under shearing forces. There is no evidence that the substrate roughness improves the adhesion of the lacquer. Analysis of the failure location identifies fracture in the tin oxide layer below the passivation layer. The findings have impacts on the next generation of passivation materials for tinplate as it has been clearly demonstrated that growth in tin oxide thickness, particularly when unstructured, has a detrimental impact on lacquer adhesion.

show abstract