Reference: WO 2013/190587
Inventors: Mariarosa Raimondo, Federica Bezzi, Magda Blosi, Claudio Mingazzini
Applicants: Consiglio Nazionale delle Ricerche (50%); Agenzia Nazionale per le Nuove Tecnologie, l’Energia e lo Sviluppo Economico Sostenibile ENEA (50%)
Filing date: 21/06/2013
Contact: Mariarosa Raimondo
A method for the treatment of metal surfaces to impart repellence towards water (hydrophobicity) and low-surface tension liquids (oleophobicity). The method comprises in succession:
- A step of deposition of a coating of metal oxide, in which on a metal surface metallica a sol is deposited made from a colloidal suspension in water of one or more metal alkoxides M(OR)n in presence of an acid catalyst, in which: M is comprised in the group consisting of Al, Ti, Si, Y, Zn, Zr; R is a linear or branched aliphatic chain C1-C4;
- A step of consolidation, wherein the coating is subjected to a temperature between 150°C and 900°C;
- A step of functionalization, in which the coating is treated with boiling water and/or steam for the realization of hydroxyl groups;
- A second step of consolidation, wherein the coating is subjected to a temperature between 150°C and 900°C, and;
- A step of fluorination, wherein the coating is treated with a fluorinated compound.
Claims
- Method for the treatment of metal surfaces for bestowing thereon a high hydrophobicity and oleophobicity, both static and dynamic, characterized in that it comprises in succession:
◦ a step of depositing a coating of metal oxide, wherein on a metal surface a sol is deposited made from a colloidal suspension in water of one or more metal alkoxides M(OR)n in the presence of an acid catalyst, in which:
▪ M is comprised in the group consisting of Al, Ti, Si, Y, Zn, Zr;
▪ R is a linear or branched aliphatic chain C1-C4 ;
and in which the transition of sol to gel is promoted by evaporation of said water from said coating;
◦ a step of consolidation, in which said coating is subjected to a temperature between 150°C and 400°C;
◦ a step of functionalization, in which said coating is treated with boiling water and/or steam for the realization of the hydroxyl groups and to modulate the surface roughness on the nanometric scale;
◦ a second step of consolidation, in which said coating is subjected to a temperature between 150°C and 400°C, and
◦ a step of superficial chemical activation, wherein said coating is treated with an alkylsilane compound. - Method for the treatment of metal surfaces according to claim 1, characterised in that in said deposition step, M is Al.
- Method for the treatment of metal surfaces according to claim 1 or 2, characterised in that in said step of functionalization, said coating is treated with boiling water and/or steam fora time of at least 30 min.
- Method for the treatment of metal surfaces according to any of the preceding claims, characterised in that in said step of superficial chemical activation said alkylsilane compound is fluorinated.
- Method for the treatment of metal surfaces according to any of the preceding claims, characterised in that it comprises a third step of consolidation, in which after being treated with an alkylsilane compound, said coating is subjected to a temperature between 50°C and 300°C.
- Method for the treatment of metal surfaces according to any of the preceding claims, characterised in that the deposition step provides that said sol is deposited by means of dip coating or spray coating or spin coating.
- Method for the treatment of metal surfaces according to any of the preceding claims, characterised in that said coating has a thickness between 50 and 500nm.
- Method for the treatment of metal surfaces according to any of the preceding claims, characterised in that in said step of superficial chemical activation said coating is treated with a fluorinated compound by means of dip coating or spray coating or spin-coating.
- Method for the treatment of metal surfaces according to claim 8, characterised In that said fluorinated compound is a fluorine alkyl silane.
- Metallic element having a surface coating made by the method according to any of the preceding claims.
