Physical Vapor Deposition

Description

At CMC, ceramic coatings are applied using plasma-assisted technology to create nanostructure and nano-layer deposits.

Further improvements to the properties of hard Physical Vapor Deposition (PVD) ceramic coatings are achieved by depositing multilayers and superlattices. These are thin films formed by alternately depositing two different components to form layered structures. Multilayers become superlattices when the distance between the different layers is less than 100Å. Research has shown that multi-layered ceramic coating structures improve: hardness, toughness, wear, corrosion, and oxidation resistance, in comparison to single-layer applications of the same material.

Technology

Nano-Arc technology combines plasma ion-assisted and plasma arc-deposition to create high-energy particles for implantation in a nano-chrystalic and multi-layered form, resulting in high-density functional coatings. PVD coatings are deposited under concurrent ion bombardment. High energy ions allow for the deposition of a dense, hard film by supplying the sputtered neutrals with sufficient energy to find a suitable nucleation site and inducing high compressive stress. PVD coatings with a hardness of 1000 – 4000HV increase the hardness of high-speed steel by up to 500%.

TiN

A general-purpose coating designed for moderate to high abrasion applications.

TiAlN

Universal high-performance coating for cutting, drilling, milling, reaming, and turning. Also suitable for dry machining.

AlTiN

High-performance coating with high aluminum content and very high heat resistance for dry high-speed machining, especially for hard machining.

CrN, CrCN

Unique coating with an optimum release for forming tools, used for molds and dies, machine components, piercing, and punching.

TiCN

A conventional carbon nitride coating for interrupted cutting, milling, tapping, stamping, punching, and forming.

TiAlCN

A special universal coating with high hardness, heat resistance and low friction coefficient. Suitable for several applications such as milling, hobbing, tapping, stamping, and punching.

ZrN

A special coating for aluminum and copper cutting tools for drilling or milling.

Properties

• Performed in a vacuum (10^-2 – 10^-4 Torr)
• Low substrate process temperature 38°C – 425°C (100F – 800F)
• Suitable for a wide range of substrates
• Substrate surface preparation (polishing, de-oxidation, de-grease, US cleaning)
• Line of sight process (inside pipes – possible with specially designed equipment)
• Ion source (high energy) and magnetron (low temperature process)
• Arc evaporator and low energy plasma generator – excellent for functional deposits
• Strong adhesion to the substrate (bend test, cutting tools)
• Average thickness: 2 – 5 µm, or (0.00008” – 0.0002”)
• Maximum thickness 25 µm
• Ideal for close tolerance components (+/- 0.0001” is achievable)
• No post heat-treating is required
• Good for sharp edges – no excessive coating build-up
• Coat mirror finishes with no post-coating polishing
• Mature technology – ready for industrial production

Applications

Cutting Tools, Punching and Forming

The use of PVD coating for metal cutting is one of the biggest advances in recent industry technology. This process is widely used in applications where a particularly sharp and hard cutting edge is required for optimal performance, such as drilling, threading and end-milling.

PVD coatings on cutting tools are an extremely profitable solution to increasing the lifespan and productivity of materials as well as reducing costs. They:

• operate faster, thereby reducing cycle times and increasing production volume;
• are resistant to all forms of wear, including abrasive, crater, built-up edges, and depth-of-cut notching;
• reduce the need for cutting fluids or coolants, thereby reducing total budget production costs by up to 15%. High-speed, dry machining involves extremely high temperatures. PVD coatings such as TiAlN poses incredible thermal stability, hot hardness, and oxidation resistance, and are able to operate dry or with minimal amounts of coolants;
• cut extremely hard materials;
• can be re-sharpened and re-coated; and
• significantly improve the surface quality of the final product.

Mold & Die Casting

PVD and Plasma-Assisted Physical Vapor Deposition (PAPVD) coatings, when used in the plastic tooling industry:

• Extend product lifespan;
• Facilitate easier demolding;
• Reduce residue and polishing requirements;
• Increase fluidity and performance of forming material;
• Lessen wear and abrasion resistance;
• Shorten cycle time;
• Diminish mold adhesion;
• Improve injection pressure, melt flow, and mold filling; and
• Enable dry or lubricant-free operation.

Automotive industry

PVD, PAPVD, and Plasma-Assisted Chemical Vapour Deposition (PACVD) coatings are used for engines, gear drives, and hydraulic components to reduce friction, thereby reducing both wear and energy loss. High friction causes excessive heating, deformation of plastics, abrasive and adhesive wear (galling), and eventually seizing tribological components. To avoid these problems, light alloy parts are coated with a high-performance, low friction coating (see Diamond-Like Carbon or DLC coatings).

Medical Components

In addition to hardness and adhesion, PVD coatings provide a number of benefits to widely used medical devices. The most significant include:

• Improved wear resistance;
• Reduced friction;
• Biocompatibility;
• Decorative colours and greater aesthetic appeal; and
• Chemical barrier against saline solutions and other oxidants.

Titanium nitride (TiN) coating is clinically being used on orthopedic implants for hip, knee, shoulder, and ankle replacements as well as dental implants.

Decorative

PVD coating has the capability to produce a broad spectrum of decorative and aesthetic colour options. Titanium, Chromium, and Zirconium are the most commonly used materials for decorative coatings.