Coating technology

The term PVD (Physical Vapour Deposition) refers to several methods for obtaining coatings by applying various physical phenomena. Their common feature is vacuum - PVD technologies occur at pressures reduced even up to 10^-5 Pa. The use of vacuum is one of the factors determining the high quality of the deposited coatings and their adhesion to the substrates.

Three stages of creating coatings by means of PVD methods should be distinguished: obtaining metal vapour phases, their transport and condensation on the substrates. The first stage is realized most often by evaporation or sputtering metallic electrode (target) - made for example of titanium (Ti). Transportation of the created vapours is performed through vacuum or low pressure gas discharge (plasma). If there are reactive ions in the plasma (e.g. nitrogen (N)), a reaction between them and metal vapour occurs (TiN compound is formed). The condensation and growth of coatings takes place on substrates heated to 200÷500 ˚C.

Why PVD technologies are made in vacuum environment? To eliminate the impurities and minimize the possibility of reactions between residual and industrial gases (e.g. O₂, CO₂ itp.) and metal vapours.

Preparation of tools before the coating process is a process that cannot be omitted. The tool grinding process usually produces irregular cutting edge geometry.