hechtlagen

Hechtlagen, also known as adhesion layers or interlayers in Dutch and German technical literature, are thin films placed between a substrate and a subsequent coating to improve bonding and performance. They are used across coatings, electronics, optics, and surface engineering to ensure reliable adhesion and longevity of the entire coated system.

The primary purpose of a hechtlage is to promote adhesion at interfaces that would otherwise be weak due to chemical, mechanical, or thermal mismatches. They can also act as diffusion barriers to prevent intermixing of substrate and top coating, relieve residual stresses from differences in thermal expansion, and improve corrosion resistance or weatherability. The choice of material and thickness depends on the substrate, the ultimate coating, and the service environment.

Common materials for adhesion layers include metallic interlayers such as titanium, chromium, or nickel; nitrides such as TiN or CrN; oxides like Al2O3 or SiO2; and organic silane-based promoters. These layers can be deposited by physical vapor deposition (PVD), chemical vapor deposition (CVD), electroplating, sputtering, or applied via sol-gel and primer treatments. In electronics and optics, thin adhesion layers are often on the order of a few nanometers to tens of nanometers; in protective or decorative coatings, thicker interlayers may be used.

Applications span metal finishing, corrosion protection, functional coatings in electronics and optics, automotive and aerospace environments, and polymer-to-metal or metal-to-glass bonding. Key considerations include compatibility with both adjoining materials, control of thickness, thermal and chemical stability, and cost.