Coating, coating system, and coating method

An anti-fouling green slurry coating, comprising:

• a galvanic protective chrome phosphate binder;
• between about 0.25% and about 35% by volume powder mixture, the powder mixture being mixed with the binder and comprising filler particles having a size in the range from nanosize to six microns with an aspect ratio of from 1:1 to 3:1, the filler particles including:
• up to 100% by weight lubricious particles, the lubricious particles selected from the group consisting of boron nitride (BN), titanium nitride (TiN), titanium oxide (TiO2), zinc (Zn), tin (Sn), oxides of zinc and tin, and combinations thereof;
• and
• a balance hard particles, the hard particles selected from the group consisting of chromium carbide (CrC), tungsten carbide (WC), silicon (Si), aluminum (Al), oxides or nitrides of silicon and aluminum, and combinations thereof;
• and
• an evaporable solvent mixed with the powder mixture and the binder in an amount sufficient that the slurry has a viscosity that resists flow due to gravity while drying, the evaporable solvent and the binder comprising a balance of the anti-fouling green slurry coating.

An anti-fouling coating system for a turbine component, comprising:

• a turbine component;
• a base coating of alumina overlying the turbine component having a first predetermined thickness;
• and
• an anti-fouling top coat further comprising:
• between about 0.25% and about 35% by volume filler particles, the filler particles having a size in the range from nanosize to six microns with an aspect ratio of from 1:1 to 3:1, the filler particles including:
• up to 100% by weight lubricious particles, the lubricious particles selected from the group consisting of boron nitride (BN), titanium nitride (TiN), titanium oxide (TiO2), zinc (Zn), tin (Sn), oxides of zinc and tin, and combinations thereof;
• and
• a balance hard particles, the hard particles selected from the group consisting of chromium carbide (CrC), tungsten carbide (WC), silicon (Si), aluminum (Al), oxides or nitrides of silicon and aluminum, and combinations thereof;
• and
• a chrome phosphate binder matrix comprising a balance of the anti-fouling top coat by volume.

A method of applying an anti-fouling coating system to a turbine component, comprising the steps of:

• providing a turbine component having an operational temperature below about 1582° F.;
• grit blasting a surface of the turbine component to produce a surface finish sufficiently rough to promote mechanical bonding of a coating layer;
• coating the grit blasted surface to a first preselected thickness with a base coat of aluminum particles in a phosphate matrix;
• heat treating the coated turbine component at a first preselected temperature for a first preselected time, curing the base coat to the turbine component;
• applying a slurry of an anti-fouling coating over the base coat to a second preselected thickness, the anti-fouling coating comprising:
• a galvanic protective chrome phosphate binder;
• between about 0.25% and about 35% by volume powder mixture, the powder mixture being mixed with the binder and comprising filler particles having a size in the range from nanosize to six microns with an aspect ratio of from 1:1 to 3:1, the filler particles including:
• up to 100% by weight lubricious particles, the lubricious particles selected from the group consisting of boron nitride (BN), titanium nitride (TiN), titanium oxide (TiO2), zinc (Zn), tin (Sn), oxides of zinc and tin, and combinations thereof;
• and
• a balance hard particles, the hard particles selected from the group consisting of chromium carbide (CrC), tungsten carbide (WC), silicon (Si), aluminum (Al), oxides or nitrides of silicon and aluminum, and combinations thereof;
• and
• an evaporable solvent mixed with the powder mixture and the binder in an amount sufficient that the slurry has a viscosity that resists flow due to gravity while drying, the evaporable solvent and the binder comprising a balance of the anti-fouling green slurry coating;
• drying the slurry;
• heat treating the anti-fouling coating applied over the coated turbine component at a second preselected temperature for a second preselected time, curing the anti-fouling coating to the base coat;
• and
• optionally burnishing the coated turbine component, thereby removing any high regions resulting from coating application.