Knowledge

PVD (Physical Vapor Deposition, physical vapor deposition) is a coating technology that deposits films on the substrate surface by converting the material source (target) into gaseous particles (atoms, molecules or ions) through physical methods in a vacuum environment. The core principle is to use vacuum conditions to reduce the scattering of gas molecules on the deposited particles, allowing the particles to move in a straight line to the substrate, thereby achieving controlled film growth.

 

Common process types include:

1. Evaporation coating: The target material is evaporated through resistance heating, electron beam heating, etc., and the gaseous particles condense and deposit on the substrate (such as the preparation of anti-reflection films for optical lenses);

 

2. Sputtering coating: High-energy ions bombard the target surface to cause target atoms to sputter and deposit (such as the preparation of metal electrodes for semiconductor chips by magnetron sputtering);

 

3. Ion plating: The deposited particles are ionized into ions and accelerated by an electric field to bombard the substrate, enhancing the adhesion of the film (such as the preparation of TiAlN wear-resistant coatings for cutting tools by vacuum arc ion plating).

 

The main features of PVD are:

- High film purity, good density, and strong adhesion to the substrate;

- Process parameters (thickness, composition, structure) can be precisely controlled with good repeatability;

- Suitable for a variety of materials (metals, ceramics, semiconductors, polymers, etc.);

- Good environmental performance (no harmful waste liquids, low exhaust gas emissions).

 

Both castings and forgings can undergo PVD (physical vapor deposition) vacuum coating, but the following conditions must be met:

1. Material suitability: The substrate must be a metal (such as steel, aluminum alloy, titanium alloy, etc.) or a ceramic material with certain electrical conductivity and heat resistance (the PVD process temperature is usually 100-500°C, and most metal castings/forgings can withstand it).

 

2. Surface pretreatment: Surface defects such as oxide scale, pores, shrinkage cavities, cracks, and folds must be removed through processes such as grinding, polishing, sandblasting, and acid washing (casting defects are more obvious and require more rigorous treatment), and the surface energy must be increased through ion bombardment and other activation treatments to ensure film adhesion.

 

Note: Castings with high carbon content such as cast iron need to pay special attention to surface defect control to avoid gas release from pores causing film failure; for aluminum alloy castings, the surface oxide film must be removed (such as alkaline washing), and a transition layer (such as nickel) may be required to enhance adhesion if necessary.

 

Vigor team has more than 20 years experience in casting, forging, cold forming processes and the post treatment, as well as a robust surface treatment supply chain. If anything we can help or any parts you want to develop, please contact us at info@castings-forging.om