A composite can include a substrate and a conversion coating overlying the substrate and comprising at least one of a zirconium oxide, a hafnium oxide, or a combination thereof. The conversion coating can be formed from a zirconia or hafnia-based complex obtained by reacting at least one of a zirconium ion source, a hafnium ion source, or a combination thereof, with a chelating compound in a reaction and another chelating compound in another reaction.

A composite can include a substrate and a conversion coating overlying the substrate and comprising at least one of a zirconium oxide, a hafnium oxide, or a combination thereof. The conversion coating can be formed from a zirconia or hafnia-based complex obtained by reacting at least one of a zirconium ion source, a hafnium ion source, or a combination thereof, with a chelating compound in a reaction and another chelating compound in another reaction.

A method of applying a trivalent chromium or chromium-free conversion coating to a metallic substrate including mixing a dye compound that interacts with electromagnetic radiation outside the human visual spectrum but not electromagnetic radiation that is within the human visual spectrum to produce an observable emission into the trivalent chromium or chromium-free conversion coating mixture to allow for inspection of the coating after applied with a correlating electromagnetic radiation source.

A problem to be solved by the present invention is to provide a method for forming a multilayer coating film, the method being capable of achieving excellent finished appearance and excellent corrosion resistance without affecting electrodeposition coatability even when a part or all of the water-washing step is omitted after chemical conversion treatment, and to provide a coated article. The invention provides a method for forming a multilayer coating film, comprising forming a chemical conversion coating film and an electrodeposition coating film on a metal substrate by Step 1 of immersing a metal substrate in a chemical conversion treatment solution to form a chemical conversion coating film, and Step 2 of omitting a part or all of the water-washing step, and performing electrodeposition coating on the metal substrate using a cationic electrodeposition coating composition to form an electrodeposition coating film, wherein when the electrodeposition coating is performed in Step 2, the solution adhered to and/or deposited on the metal substrate has an electrical conductivity of less than 10,000 S/cm.

A problem to be solved by the present invention is to provide a method for forming a multilayer coating film, the method being capable of achieving excellent finished appearance and excellent corrosion resistance without affecting electrodeposition coatability even when a part or all of the water-washing step is omitted after chemical conversion treatment, and to provide a coated article. The invention provides a method for forming a multilayer coating film, comprising forming a chemical conversion coating film and an electrodeposition coating film on a metal substrate by Step 1 of immersing a metal substrate in a chemical conversion treatment solution to form a chemical conversion coating film, and Step 2 of omitting a part or all of the water-washing step, and performing electrodeposition coating on the metal substrate using a cationic electrodeposition coating composition to form an electrodeposition coating film, wherein when the electrodeposition coating is performed in Step 2, the solution adhered to and/or deposited on the metal substrate has an electrical conductivity of less than 10,000 S/cm.

An aqueous acidic composition for treating metal surfaces, the composition including the following components: a) at least one water soluble or water dispersable anionic polyelectrolyte; b) at least one organofunctional silane including one or more reactive functional groups selected from the group including amino, mercapto, methacryloxy, epoxy and vinyl; c) at least one water dispersible solid wax wherein the weight ratio between components a:b is in the range of 1:2-4:1, based on dry matter; the weight ratio between components (a+b):c is in the range of 1:3-3:1, based on dry matter, and wherein components a and b may be presentat least partiallyas their graft reaction product. Another aspect is a treating method using this composition and use of the thus treated metal surface.

A chromium-free conversion coating is prepared by the addition of inorganic metallic salts and one or more silanes to dispersions of conducting polymers which are then exposed to alloys of aluminum or other metals. Advantageously, the performance of the coating is comparable to that of conventional chromium-based methods for a number of aluminum alloys having particular significance in the manufacture of aircraft.

The corrosion resistance of conversion-coated metal substrate surfaces is further enhanced by treating such surfaces with aqueous mixtures of preformed reaction products obtained by reacting catechol compounds, such as dopamine or a dopamine salt, and functionalized co-reactant compounds, such as a polyethyleneimine.

The corrosion resistance of conversion-coated metal substrate surfaces is further enhanced by treating such surfaces with aqueous mixtures of preformed reaction products obtained by reacting catechol compounds, such as dopamine or a dopamine salt, and functionalized co-reactant compounds, such as a polyethyleneimine.

Embodiments relate to a cerium-containing nano-coating composition, the composition including an amorphous matrix including one or more of cerium oxide, cerium hydroxide, and cerium phosphate; and crystalline regions including one or more of crystalline cerium oxide, crystalline cerium hydroxide, and crystalline cerium phosphate. The diameter of each crystalline region is less than about 50 nanometers.