Hydrothermal Corrosion of Double Layer Glass/Ceramic Coatings Obtained from Preceramic Polymers

Abstract

Polysilazane-based double layer composite coatings consisting of a polymer-derived ceramic (PDC) bond-coat and a PDC top-coat that contains ceramic passive and glass fillers were developed. To investigate the environmental protection ability of the prepared coatings, quasi-dynamic corrosion tests under hydrothermal conditions were conducted at 200 °C for 48–192 h. The tested PDC coatings exhibited significant mass loss of up to 2.25 mg/cm2 after 192 h of corrosion tests, which was attributed to the leaching of elements from the PDC coatings to the corrosion medium. Analysis of corrosion solutions by inductively coupled plasma optical emission spectrometry (ICP-OES) confirmed the presence of Ba, Al, Si, Y, Zr, and Cr, the main component of the steel substrate, in the corrosion medium. Scanning electron microscopy (SEM) of the corroded surfaces revealed randomly distributed globular crystallites approximately 3.5 µm in diameter. Energy-dispersive X-ray spectroscopy (EDXS) of the precipitates showed the presence of Ba, Al, Si, and O. The predominant phases detected after corrosion tests by X-ray powder diffraction analysis (XRD) were monoclinic and cubic ZrO2, originating from the used passive fillers. In addition, the crystalline phase of BaAl2Si2O8 was also identified, which is in accordance with the results of EDXS analysis of the precipitates formed on the coating surface.

Special Issue: “Surface Engineering and Coating Technologies for Corrosion and Tribocorrosion Resistance”

“…These types of PDC glass/ceramic coatings are suitable for the protection of stainless steel from oxidation at temperatures up to 950 • C [4]. The research presented in this work [3] is comprehensive, involving: quasi-dynamic corrosion tests under hydrothermal conditions at 200 • C, for 48-192 h; mass loss/gain measurements; the analysis of corrosion solutions using inductively coupled plasma-optical emission spectrometry; Raman spectroscopy; scanning electron microscopic examination; and EDXS and XRD analysis. The presented research provides an insight into the degradation mechanisms of coatings during various stages of the hydrothermal process.…”

“…The electrochemical response of different elements and phases will affect the corrosion properties of composite coatings. In the work reported in [3], the authors investigated the hydrothermal corrosion behaviour of double-layer glass/ceramic composite coatings with passive fillers. The coatings were produced via the polymer-derived ceramic (PDC) synthesis route.…”

Cold-Sprayed Composite Metal-Fluoropolymer Coatings for Alloy Protection against Corrosion and Wear

“…However, the most rational, effective, and inexpensive method of protection is the application of coatings [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. It is possible to use a paintwork material [13,19,30] (including those with additives of nanoparticles [25,[31][32][33][34][35][36][37][38] and inhibitors [13,14,20,[39][40][41][42][43][44][45][46][47]) and zinc coating to protect the material against its intensive destruction [48].…”

Surface Engineering & Coating Technologies for Corrosion and Tribocorrosion Resistance

“…The electrochemical responses of different elements and phases will affect the corrosion properties of composite coatings. In the work reported in [ 5 ], Parchovianská et al investigated the hydrothermal corrosion behavior of double-layer glass/ceramic composite coatings with passive fillers. The coatings were produced using the polymer-derived ceramic (PDC) synthesis route, and this type of PDC-produced glass/ceramic coatings are suitable for the protection of stainless steel from oxidation at temperatures up to 950 °C [ 6 ].…”