In the field of vacuum coating technology, thin films can generally be classified into metal coatings and non-metal coatings, depending on the coating material. These two categories differ significantly in deposition mechanisms, film properties, and application areas. Understanding their distinctions helps process engineers select the most suitable materials and parameters for production.
I. Characteristics and Principles of Metal Coatings
Metal coating refers to depositing metallic targets onto substrates through techniques such as thermal evaporation or magnetron sputtering.
Typical Materials: Al, Cu, Ag, Au, Ti, Cr, etc.
Deposition Mechanism: Metal atoms, after being evaporated or sputtered in vacuum, undergo minimal chemical reaction and condense in their intrinsic state onto the substrate.
Key Properties:
High electrical conductivity
Excellent reflectivity, widely used in optical mirrors
Strong adhesion and good ductility
Typical Applications:
Electrode layers in semiconductor devices
Optical reflective coatings
Decorative coatings
II. Characteristics and Principles of Non-metal Coatings
Non-metal coatings mainly include oxides, nitrides, and carbides, usually deposited by reactive sputtering or ion plating.
Typical Materials: SiO₂, TiO₂, Al₂O₃, Si₃N₄, DLC (Diamond-Like Carbon), etc.
Deposition Mechanism: Metallic targets react with process gases (e.g., O₂, N₂, CH₄), forming compound species that deposit onto the substrate.
Key Properties:
High hardness and wear resistance
Excellent optical properties, such as high transparency or anti-reflection performance
Strong electrical insulation
Typical Applications:
Optical coatings (e.g., AR films, filter coatings)
Protective layers (e.g., DLC anti-scratch films)
Dielectric layers in electronic devices
III. Core Differences Between Metal and Non-metal Coatings
Film Properties:
Metal coatings emphasize conductivity and reflectivity, making them ideal for electrical and decorative applications.
Non-metal coatings focus on optical control, insulation, and mechanical durability.
Deposition Processes:
Metal coatings are typically deposited via physical vapor deposition (PVD) with relatively simple processes.
Non-metal coatings require reactive gases, resulting in narrower process windows and stricter parameter control.
Application Fields:
Metal coatings: electronic circuits, reflective mirrors, decorative films.
Non-metal coatings: optical lenses, touch panels, protective layers.
IV. Complementary Roles in Industrial Applications
In practice, metal and non-metal coatings are often combined:
ITO transparent conductive films consist of oxide materials (non-metal properties) while also providing electrical conductivity (metal-like behavior).
In decorative coatings, a metal layer (e.g., Ti or Cr) is often deposited first, followed by a non-metallic layer (e.g., TiN or TiCN), creating composite films that combine decorative appearance with wear resistance.
Metal and non-metal coatings each offer unique advantages in principle and performance. Metal coatings emphasize conductivity and reflectivity, while non-metal coatings excel in optical, insulating, and protective functionalities. In vacuum coating applications, selecting the appropriate film combination according to product requirements is crucial to enhancing both performance and market competitiveness.
—This article was published by vacuum coating equipment manufacturer Zhenhua Vacuum
Post time: Aug-18-2025