A method of forming a protective coating. The method includes providing a substrate including at least one chemical element and a surface; forming a basecoat composition including an aluminium phase including aluminium;

applying the basecoat composition on the surface of the substrate to form a basecoat layer; heating the basecoat layer to a first temperature for a predetermined period of time; applying a glow discharge plasma on the basecoat layer; and heating the basecoat layer to a second temperature greater than the first temperature, in order to activate an exothermic reaction between at least the aluminium phase of the basecoat layer and the at least one chemical element of the substrate, wherein the exothermic reaction forms the protective coating on the surface of the substrate.

In a process for coating a surface of a substrate with a metal layer zinc is used as a coating agent. Zinc metal and said substrate are brought together at an elevated temperature in a liquid diffusion medium to allow a diffusion of zinc through said diffusion medium to said surface of said substrate. Said diffusion medium comprises a molten salt liquid, particularly molten salt bath, of at least one salt that is maintained at a bath temperature of between 200° C. and 800° C. Said substrate and zinc as a coating agent are heat treated in said bath to promote said diffusion of zinc to said surface of said substrate.

In a process for coating a surface of a substrate with a metal layer zinc is used as a coating agent. Zinc metal and said substrate are brought together at an elevated temperature in a liquid diffusion medium to allow a diffusion of zinc through said diffusion medium to said surface of said substrate. Said diffusion medium comprises a molten salt liquid, particularly molten salt bath, of at least one salt that is maintained at a bath temperature of between 200° C. and 800° C. Said substrate and zinc as a coating agent are heat treated in said bath to promote said diffusion of zinc to said surface of said substrate.

A method of coating a component including aluminizing an array of internal passageways within the component; and chromizing a portion of the array of internal passageways within the component. A component, including an airfoil having an array of aluminized internal passageways, the array of aluminized internal passageways chromized up to a demarcation.

A method of coating a component including aluminizing an array of internal passageways within the component; and chromizing a portion of the array of internal passageways within the component. A component, including an airfoil having an array of aluminized internal passageways, the array of aluminized internal passageways chromized up to a demarcation.

A method of coating a component including aluminizing an array of internal passageways within the component; and chromizing a portion of the array of internal passageways within the component. A component, including an airfoil having an array of aluminized internal passageways, the array of aluminized internal passageways chromized up to a demarcation.

A method of coating a component including aluminizing an array of internal passageways within the component; and chromizing a portion of the array of internal passageways within the component. A component, including an airfoil having an array of aluminized internal passageways, the array of aluminized internal passageways chromized up to a demarcation.

A process of converting an outer layer of an object made of a refractory metal, such as titanium, into a carbide of the refractory metal. A molten metal, such as molten lithium, is placed adjacent the outer surface of the object. The lithium does not react with the titanium, nor is it soluble within the titanium to any significant extent at the temperatures involved. The molten lithium contains elemental carbon, that is, free carbon atoms. At high temperature, the carbon diffuses into the titanium, and reacts with titanium atoms to form titanium carbide in an outer layer. Significantly, no other atoms are present, such as hydrogen or oxygen, which can cause problems, because they are blocked by the molten lithium.

A process of converting an outer layer of an object made of a refractory metal, such as titanium, into a carbide of the refractory metal. A molten metal, such as molten lithium, is placed adjacent the outer surface of the object. The lithium does not react with the titanium, nor is it soluble within the titanium to any significant extent at the temperatures involved. The molten lithium contains elemental carbon, that is, free carbon atoms. At high temperature, the carbon diffuses into the titanium, and reacts with titanium atoms to form titanium carbide in an outer layer. Significantly, no other atoms are present, such as hydrogen or oxygen, which can cause problems, because they are blocked by the molten lithium.

A method of applying a protective coating to an article comprises the steps of a) depositing aluminum in a surface region of an article, and b) depositing chromium is the surface region of the article subsequent to step a), whereby at least a portion of the chromium replaces at least a portion of the aluminum. Another method and an article are also disclosed.