Special coatings & applications

In dry environments, such as dry gas or vacuum, regular DLC coatings such as Tribobond^™ 41/42/43 exhibit high friction and wear rates. Responding to the need to provide protection in such conditions, Ionbond developed the Tribobond^™ 55 coating, specifically designed to overcome this limitation. This was achieved by modifying the structure and composition of the functional DLC layer.

One of the limitations of physical and plasma-assisted chemical vapor deposition (PVD and PACVD) technologies is their inability to deposit coatings into inner surfaces, like holes and cavities with a high aspect ratio. Chemical vapor deposition (CVD) technology, however, allows coating of inner surfaces of virtually unlimited length and aspect ratio. This is achieved by management of reactive gas flows, a technique mastered by Ionbond engineers on many different products. High-quality coatings such as TiN, TiCN, ZrN or Al₂O₃ can be produced on inner diameters of various geometry, size and length.

Conventional physical and chemical vapor deposition (PVD and CVD) coatings offer only marginal improvements in corrosion resistance. This is primarily due to the coating structure, which allows interaction of the corrosive medium with the substrate through grain boundaries and other defects of the coating.

Ionbond offers a number of possible solutions to improve corrosion performance of sensitive substrates.

Aluminum coatings
Aluminum coatings offer remarkable improvement in corrosion resistance. The coating acts as a sacrificial anode in galvanic corrosion, thus protecting the substrate. Ion vapor deposition (IVD) is a common method of producing such a film. Ionbond engineers have developed an alternative technique to produce Al coatings using cathodic arc or sputtering PVD techniques. The aluminum coatings produced by PVD methods fully meet strict US defense specifications (MIL-SPEC) and offer some performance advantages compared to coatings deposited by other methods.

Silicon oxide PACVD films
Another effective solution for corrosion protection is a PACVD silicon oxide film. These films are ideal for forming a completely sealed surface, effectively preventing the corrosive medium from interacting with the substrate. The SiOx coatings are produced using a pure PACVD process, thus avoiding an undesirable structure of the film. These coatings have demonstrated corrosion-free performance for up to 500 hours of the salt spray test. Unlike aluminum coatings, SiOx films have high hardness, offering some wear protection. They can be produced as a top layer on regular Tribobond^™ films.

The unique nature of diamond-like carbon (DLC) coatings allows engineers to tune their properties to suit a particular application. This is  achieved either by modification of the deposition process  or by doping the DLC film with certain elements. Ionbond engineers have developed customized DLC coatings for a variety of special applications, such as:

• films with a specific resistivity/conductivity range
• films with modified surface energy to achieve better hydrophobic properties
• films for non-conductive substrates, like glass or ceramics
• films suitable for certain plastic substrates

Are you interested in a different application? The Ionbond engineering team is constantly working on expanding the application range of DLC coatings and is always open to discuss custom applications.