Gas-turbine blade and method of manufacturing a gas-turbine blade

A method of manufacturing a gas-turbine blade, which comprises the following steps:

• casting a hollow, supporting metal blade body with a blade airfoil having an outer surface and a hollow interior space;
• forming a multiplicity of elevations with top sides on the outer surface of the blade airfoil;
• boring impact cooling bores between the elevations from the outer surface to the hollow interior space;
• applying a coating of a heat-resistant, removable material and thereby, filling intermediate spaces between the elevations and closing the impact cooling bores;
• applying a covering coat adhering to the top sides of the elevations;
• and
• leaching the heat-resistant, removable material from the intermediate spaces between the elevations and the covering coat.

A method of manufacturing a gas-turbine blade, which comprises the following steps:

• casting a hollow, supporting metal blade body with a blade airfoil having an outer surface and a hollow interior space;
• forming a multiplicity of elevations with top sides on the outer surface of the blade airfoil;
• boring impact cooling bores between the elevations from the outer surface to the hollow interior space;
• applying a coating of a ceramic material and thereby filling intermediate spaces between the elevations and closing the impact cooling bores, and drying and sintering the ceramic material;
• applying a covering coat adhering to the top sides of the elevations;
• and
• removing the ceramic material from the intermediate spaces between the elevations and the covering coat.

A method of manufacturing a gas-turbine blade, which comprises the following steps:

• casting a hollow, supporting metal blade body with a blade airfoil having an outer surface and a hollow interior space;
• forming a multiplicity of elevations with top sides on the outer surface of the blade airfoil;
• boring impact cooling bores between the elevations from the outer surface to the hollow interior space;
• applying a coating of a heat-resistant, removable material and thereby filling intermediate spaces between the elevations and closing the impact cooling bores;
• applying a covering coat adhering to the top sides of the elevations;
• removing the heat-resistant, removable material from the intermediate spaces between the elevations and the covering coat;
• and
• subjecting the metal blade body with the covering coat to heat treatment for securely connecting the covering coat to the top sides of the elevations by diffusion.

A gas-turbine blade, comprising:

• a hollow, supporting metal blade body having a blade airfoil with an outer surface having a multiplicity of elevations with top sides formed thereon;
• said blade airfoil having a multiplicity of impact cooling bores formed therein between said elevations;
• and
• a thin covering coat adhering to said top sides of said elevations, said covering coat having a thickness of between 0.1 mm and 0.5 mm, said covering coat having a multiplicity of oblique film-cooling bores formed therein.

A gas-turbine blade, comprising:

• a hollow, supporting metal blade body having a blade airfoil with an outer surface having a multiplicity of peg-shaped elevations with top sides formed thereon;
• said blade airfoil having a multiplicity of impact cooling bores formed therein between said peg-shaped elevations;
• and
• a thin covering coat adhering to said top sides of the elevations, said covering coat having a multiplicity of oblique film-cooling bores formed therein.