Component having a film cooling hole

1. A component having a film cooling hole, comprising:

a component substrate; and

a layer arranged on the substrate where the film cooling hole comprises a diffuser in an outer region and a hot gas flows over the film cooling hole in an overflow direction, the film cooling hole comprising a lower part, and the diffuser adjoins the lower part as part of the film cooling hole and

wherein,

the diffuser is substantially arranged in the layer,

the overall coating thickness is 60% of an overall length of the diffuser as measured along a normal to the outer surface of the layer includes a first length which is completely arranged in an overall coating thickness and a second length which is arranged in the substrate whereby the first length is significantly less than the second length,

the diffuser widens in the plane of the outer surface of the layer in the overflow direction at an angle to the overflow direction transversely to the overflow direction,

wherein the diffuser consists of a continuation of the contour of the lower part and an appendage, and only the appendage of the diffuser widens toward the outer surface so that it is shaped trapezoidally in the outer surface, and

wherein the diffuser has a longitudinal length in the plane of the outer surface in the overflow direction equal to 3 mm,

wherein a greatest transverse length of the diffuser in the plane of the outer surface measured perpendicularly to the overflow direction includes a first size of 2+−0.2 mm for rotor blades and a second size of 4+−0.2 mm for guide vanes,

wherein the widening of diffuser begins on a widening front edge, at the appendage, and widens in the overflow direction, and

wherein the overflow direction makes an acute angle with a lateral delimiting line of the appendage in the plane of the outer surface.

2. The component as claimed in claim 1 , wherein the acute angle is 10°±10°.