Corrosion-Resistant Zeolite Silicalite-1 Coatings Synthesized by Seeded Growth

Abstract

It has been proved that zeolite MFI coatings synthesized by in situ hydrothermal synthesis is corrosion-resistant. Pure silica zeolite MFI (silicalite-1) coatings on aluminum alloy 1060 plates seeded by brush-coating a seed paste and leveling the seed layer with fingers have been synthesized by the seeded growth method in this study. The seed paste is composed of seeds, silica sol, and water. The effects of the seed/sol ratio and the seed crystal size on the properties of silicalite-1 coatings are investigated in detail. The corrosion protection performance of the silicalite-1 coatings on aluminum alloy plates is determined by a direct current polarization technique. The silicalite-1 coatings (∼3 μm thick) obtained by the seeded growth method at 150 °C for 3 h are found to be highly b-oriented and corrosion-resistant in severely corrosive acidic aqueous solution (0.5 M H2SO4) and sodium chloride aqueous solution (0.5 M) exposed to air at room temperature. The optimum seed/sol ratio and the seed crystal size in the seed paste are 6.0 and 500 nm, respectively.

Uniform hierarchical MFI nanosheets prepared via anisotropic etching for solution-based sub–100-nm-thick oriented MFI layer fabrication

“…The first step involves facile preparation of MFI NSs. Parent MFI crystals, which were synthesized by a simple hydrothermal method (26), exhibited uniform coffin-shaped morphology (0.9 m × 0.45 m × 1.2 m; Fig. 2A).…”

A Brief Overview on the Anticorrosion Performances of Sol-Gel Zeolite Coatings

“…Although some troubles related to costs and technological scale-up issues have limited the development of this technology. Furthermore-notwithstanding the in-situ crystallization (e.g., by hydrothermal process) leading to well-adherent pure zeolite layers-low density, porous, or cracked coatings are often obtained during the synthesis process caused by a random and not-easily-controllable nucleation of zeolite crystals on the support [56,57].…”

Fabrication of b‐Oriented MFI Zeolite Films under Neutral Conditions without the Use of Hydrogen Fluoride

“…The localized weak alkaline environment created by the dissolved Na 2 Os pecies from the substrate is identified as the key factor for the depolymerization of fumed silica and subsequently the in-plane growth of zeolite seed layers.C ontinuous b-oriented MFI films can also be synthesized on other substrates in the presence of ag lass plate or at race amount of NaOH, which making our neutral synthesis route promising for the direct synthesis of MFI zeolite films and membranes on various substrates.MFI zeolite films and membranes have found many applications in the field of separation, [1][2][3][4][5][6][7][8] catalysis, [9,10] sensors, [11,12] and corrosion protection. [13,14] One particularly interestingb ut challenging issue is the fabrication of dominantly b-oriented pure silica MFI zeolite films.In2001, Wang et al for the first time reported that the delicate manipulation of the composition of the synthesis solution produced continuous b-oriented MFI thin films by in situ crystallization. [15] Thef ilm was then successfully used as al ow-k intermetallic dielectric.…”