STRUCTURAL COMPONENT COATED WITH A HARD MATERIAL AND COMPRISING AN INTERMEDIATE LAYER FOR IMPROVING THE ADHESIVE STRENGTH OF THE COATING

Structural components that are subject to high stresses, especially caused by wear, can be protected by coating them with a hard material. For metal-cutting tools it is for example known that their wear resistance can be improved by coating them with a hard material. Different thermal expansion coefficients of the substrate material and the coating material and different layer materials in a multilayer coating may produce great stresses. The stress increases as the thickness of the coating increases, thereby increasing the danger of the coating chipping off. In order to solve this problem, the invention proposes an intermediate layer (5) to be interposed between at least two layers (4, 9) of the coating (3), said intermediate layer mainly or exclusively consisting of a material component (6, 8) of an element of the fourth to eighth subgroup of the fourth and fifth period of the periodic system. Componentes estructurales que estan sujetos a cargas elevadas, causadas especialmente por desgaste, pueden ser protegidos mediante su revestimiento con un material duro. Para herramientas de arranque de virutas se conoce por ejemplo el sistema de que es posible mejorar su resistencia al desgaste revistiendolos con un material duro. Los coeficientes diferentes de expansion termica del material substrato y del material de revestimiento y el uso de materiales de las capas diferentes en un sistema de revestimiento de capas multiples, pueden generar tensiones elevadas. La tension aumenta a medida a que sea mayor el espesor del revestimiento y asi aumenta el peligro de que se vaya desprendiendo este revestimiento. A fin de resolver este problema, la invencion propone colocar una capa intermedia (5) la cual se intercala entre un minimo de dos capas (4, 9) del revestimiento (3), y esta capa intermedia consta principal o exclusivamente de un componente del material (6, 8) correspondiente a un elemento del cuarto al octavo subgrupo del cuarto y quinto periodo del sistema periodico.