Anodic phosphonic/phosphinic acid duplex coating on valve metal surface

A method of producing a functionalized layer and a non-porous barrier-type oxide layer on an aluminum substrate, the barrier-type layer between the substrate and the functionalized layer, the method comprising the steps of:

• (a) providing an aluminum substrate as an anode in an anodizing electrolyte comprised of a monomeric phosphorus-containing acid selected from phosphinic and phosphonic acids;
• and
• (b) anodizing said substrate under conditions to form a non-porous barrier aluminum oxide layer on said aluminum substrate and a functionalized layer on a surface of said barrier layer;
• (c) producing the oxide layer at less than 25 .ANG./V and at a weight gain of less than 0.9 mg/coulomb, the functionalized layer protecting said oxide layer against chemical attack by said electrolyte during anodizing.

A method of producing a functionalized layer and a non-porous barrier-type oxide layer on an aluminum sheet stock fabricated from an Aluminum Association alloy selected from 82, AA5042, AA5082 and AA5352, the barrier layer between the substrate and the functionalized layer, the method comprising the steps of:

• (a) providing an aluminum substrate as an anode in an anodizing electrolyte comprised of a water containing solution having a monomeric phosphorus-containing acid selected from phosphinic and phosphonic acids;
• (b) anodizing said substrate under conditions to form a non-porous barrier aluminum oxide layer having a density of 2.8 to 3.2 gms/cc and having a thickness of 100 to 5000 .ANG. on said aluminum substrate and a functionalized layer on a surface of said barrier layer, the functionalized layer having a thickness of less than 200 .ANG., the oxide and functionalized layer having a phosphorus to aluminum ratio of 0.001 to 0.5;
• and
• (c) producing the oxide layer at less than 25 .ANG./V and at a weight gain of less than 0.9 mg/coulomb, the functionalized layer protecting said oxide layer against chemical attack by said electrolyte during anodizing.

A method of producing a duplex layered material comprised of a functionalized layer supported on an aluminum member by an oxide layer on the aluminum member, the functionalized layer maintained at a controlled thickness while the oxide layer is permitted to grow, the method comprising the steps of:

• (a) providing said aluminum member in an aqueous anodizing electrolyte containing a monomeric phosphorus containing acid selected from phosphinic and phosphonic acid and combinations thereof;
• (b) anodizing said member under conditions to form a non-porous aluminum oxide layer on said member and a functionalized layer on said oxide layer, the oxide layer growing in thickness during said anodizing and said functionalized layer remaining relatively constant in thickness during said anodizing;
• and
• (c) producing the oxide layer at less than 25 .ANG./V and a weight gain of less than 0.9 mg/coulomb, the functionalized layer protecting said oxide layer against attack by said electrolyte during anodizing.

A method of producing a duplex layered material comprised of a functionalized layer supported on an aluminum member by an oxide layer on the aluminum member, the functionalized layer remaining at a relatively constant thickness while the oxide layer is permitted to grow, the method comprising the steps of:

• (a) providing said aluminum member in an aqueous solution containing a monomeric phosphorus containing acid selected from phosphinic and phosphonic acid and combinations thereof;
• (b) applying a functionalized layer comprised of the reaction product of said phosphinic and phosphonic acid;
• (c) anodizing said member in said solution under conditions to form a non-porous aluminum oxide layer on said member and a functionalized layer on said oxide layer, the oxide layer growing in thickness during said anodizing and said functionalized layer remaining relatively constant in thickness during said anodizing;
• (d) producing the oxide layer at less than 25 .ANG./V and a weight gain of less than 0.9 mg/coulomb, the functionalized layer protecting said oxide layer against attack by said electrolyte during anodizing.

A method of producing a duplex layered material comprised of a functionalized layer supported on an aluminum member by an oxide layer on the aluminum flat rolled stock comprised of an Aluminum Association alloy selected from AA1000, AA3000 and AA5000 alloys, the functionalized layer remaining at a relatively constant thickness while the oxide layer is permitted to grow, the method comprising the steps of:

• (a) providing said aluminum member in a solution containing an aqueous monomeric phosphorus containing acid selected from phosphinic and phosphonic acid and combinations thereof;
• (b) applying a functionalized layer comprised of the reaction product of said phosphinic and phosphonic acid, the functionalized layer having a thickness less than 200 .ANG.;
• (c) anodizing said member in said solution under conditions to form a non-porous aluminum oxide layer on said member underneath said functionalized layer, the oxide layer growing in thickness during said anodizing and said functionalized layer remaining relatively constant in thickness during said anodizing, the oxide layer having a density in the range of 2.8 to 3.2 gms/cc and a thickness in the range of 100 to 5000 .ANG., the duplex layer having a phosphorus to aluminum ratio of 0.001 to 0.5;
• and
• (d) producing the oxide layer at less than 25 .ANG./V and a weight gain of less than 0.9 mg/coulomb, the functionalized layer protecting said oxide layer against attack by said electrolyte during anodizing.

A method of producing a polymer coated aluminum substrate by providing a functionalized layer and non-porous barrier oxide layer on an aluminum substrate, the barrier layer intermediate the substrate and the functionalized layer, the method comprising the steps of:

• (a) providing an aluminum substrate as an anode in an anodizing electrolyte comprised of a water containing solution having a monomeric phosphorus-containing acid selected from phosphinic and phosphonic acids;
• (b) anodizing said substrate under conditions to form a non-porous barrier aluminum oxide layer on said aluminum substrate and a functionalized layer on a surface of said barrier layer;
• (c) producing the oxide layer at less then 25 .ANG./V and a weight gain of less than 0.9 mg/coulomb, the functionalized layer protecting said oxide layer against chemical attack by said electrolyte during anodizing;
• and
• (d) bonding a polymer coat to said functionalized layer to provide a polymer coated aluminum substrate.

A method of producing a polymer coated aluminum substrate by providing a functionalized layer and a non-porous barrier oxide layer on an aluminum flat rolled product fabricated from an Aluminum Association alloy selected from AA1000, AA3000 and AA5000 alloys, the barrier layer intermediate the substrate and the functionalized layer, the method comprising the steps of:

• (a) providing an aluminum substrate as an anode in an anodizing electrolyte comprised of a water containing solution having a monomeric phosphorus-containing acid selected from phosphinic and phosphonic acids;
• (b) anodizing said substrate under conditions to form a non-porous barrier aluminum oxide layer on said aluminum substrate and a functionalized layer on a surface of said barrier layer, the oxide layer having a density of 2.8 to 3.2 gms/cc and having a thickness in the range of 100 to 5000 .ANG., the functionalized layer having a thickness of less than 200 .ANG., both layers having a phosphorus to aluminum ratio in the range of 0.001 to 0.5;
• (c) producing the oxide layer at 12 to 16 .ANG./V and a weight gain in the range of 0.03 to 0.2 mg/coulomb, the functionalized layer protecting said oxide layer against chemical attack by said electrolyte during anodizing;
• and
• (d) bonding a polymer coat to said functionalized layer to provide a polymer coated aluminum substrate.