physical vapour deposition abbr., PVD otherwise PVD-process (rus. физическое осаждение из газовой фазы otherwise diffusion metallization) — vacuum coating technology (thin films) from the vapour (gas) phase, where the coating is done by direct condensation of the applied material vapour. 

Description

PVD-methods can be executed in two ways: 1) thermal evaporation, and 2) ion-plasma sputtering.

In thermal evaporation, the sputtered material is heated to a sufficiently high temperature, and at such temperatures some atoms or molecules acquire enough energy to break chemical bonds and leave the substance. In this case the liquid evaporates and the solids sublimate.

There exist the following heating processes.

1. Thermal evaporation (resistive heating) (TVD-process). The substance is thermally heated in an ultrahigh vacuum (≤ 1.3 · 10-8 Pa), to the desired temperature of evaporation, with its atoms and molecules fall to the substrate and undergo condensation.

2. Electron-beam evaporation (EBVD-process).

A metal sample that serves as the anode receives the flow of electrons with energies of several keV emitted by the cathode, this leads to the continuous evaporation of atoms.

3. Laser ablation (see pulsed laser deposition, PLD-process).

The target is exposed to a pulsed UV radiation by an excimer or Nd:YAG laser. The radiation intensity is 108-109 W/cm2, the duration is a few nanoseconds, which is sufficient for ablation of materials (metals, metal oxides) at the target hot spot.

4. Electric arc evaporation (arc-PVD-process).

A vacuum arc is initiated between the anode and the cathode and it vaporizes the cathode material. The process takes place in an inert gas environment at low pressures of 0.133-13.3 Pa and the epitaxy temperature lower than the one for thermal evaporation methods.

In ion-plasma sputtering, the target surface is bombarded by atoms, ions or molecules with energy exceeding the binding energy of target atoms. As a rule, noble gas ions are used for bombardment, since they are easy to accelerate to the required energy in the electric field and they are chemically inert.

The vast temperature variability in coated zones makes these methods universal for coating hard-alloy tools. These technologies are also universal as they enable a wide range of monolayer, multilayer and composite coatings based on nitride, carbide, carbonitride compounds of refractory metals Ti, Zr, Hf.

Illustrations



Рис. 1. Вакуумная печь для нанесен

Рис. 1. Вакуумная печь для нанесения нанопокрытий PVD-методом


Source: Балабанов В.И.
Рис. 2. Схема PVD-метода нанесения нанопокрытия:

Рис. 2. Схема PVD-метода нанесения нанопокрытия:

1 – дверь; 2 – обрабатываемая деталь; 3 – металлизатор; 4 – вакуумная камера (печь); 5 – трубопровод к вакуумному насосу; 6 – нагревательный элемент


Source: Балабанов В.И.
Рис. 3. Различные комбинации получаемых покрытий: 
а) слоистое (двухкомпон

Рис. 3. Различные комбинации получаемых покрытий:

а) слоистое (двухкомпонентное) покрытие; б) многослойные (например, металлополимерные) покрытия; в) композиционные покрытия


Source: Балабанов В.И.

Author

  • Saranin Alexander A.

Source

  1. Oura K. et al. Surface Science: An Introduction // Springer, 2010 - 452 pp. Balabanov V.I., Balabanov I.V. Nanotechnology: Truth and Fiction (in Russian). Moscow: Eksmo, 2010. - 384 p.

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