General Observations

The cathodic arc deposition process appears to have strong, features for both reactive and metal film deposition;. These are:

* Highly ionized, high ionization efficency and high energy evaporant.

* Low temperature coating capabi1ities.

* Good adhesion, uniformity and film density.

* High deposition rates.

* Flexible source-to-substrate distance.

Limits that exist in the arc deposition technology:

* Deposition of dielectrics is not yet available.

* Difficulty in deposition of hot pressed or sintered targets.

* Varied results in totally macrofree films.

The application of cathodic arc coatings to tooling has been well established and is being used by tool manufacturers and users. The arc coatings are being used in decorative applications for jewelry and watchbands, and decorative fixtures. The use of arc produced coatings for piece parts in the automobile market, the construction markets, and the aircraft market seem very promising when we consider:

1) Cost of the Component Coatings have increased the life of some components by a factor of two or more times, with a small added cost. A fuel component, made of stainless steel, was tested with and without coating (TiN) to determine the wear. The coated part wore less than 5 millionths of an inch while the stainless part wore 1^0

times improvement. The cost of coating the part was less than 5V. of the cost of the

2) Cost of Present Processes Plating and other coating processes involving chemicals and waste disposal can contribute a large percentage of the cost of a production part. Substitution of chrome plating with cathodic arc deposition has been demonstrated as an economical alternative and it is anticipated that plating costs will continue to escalate rapidly. The availability of platers to provide the chrome

V-ll may also be lower due to requirements for upgrading facilities to meet new pollution standards.

Volume

Parts manufactured in large volumes requiring hard or corrosion protected coatings may now be economically coated with the cathodic arc process. Volume production lends itself to inline vacuum systems which process parts which are palletized and coated on a semi-continuous basis. These systems maintain the coating chamber at process conditions thus minimizing the cycle time for pump down and venting. The flow of parts in the chamber minimizes costs and increases the degree of uniformity from part to part.

A recent study of parts that now require chrome plating concluded that substitution with cathodic arc applied TiN was both design appropriate and economical. TiN, with its higher hardness» good adhesion) and low susceptibility to cracking or spalling improves the part performance. The ability to coat to dimension removes the requirement to machine after coating. The study concluded that the coating system, its cleaning facility, and the operating cost reduced the coating costs 21 to SV/..

The vacuum equipment was required to coat approximately 10 million parts per year. This required a system consisting of a load lock chamber where the parts are loaded into the unit, a dwell/heat sction, a processing/coating area, and exit/cool down chamber. The parts are programmed through the unit to coat the parts with 3Hm of TiN on specific areas only. Horizontal pallets transport the parts through the chamber while top mounted cathodes are positioned to coat the ends and sides of the parts. The overall dimensions of the unit are approximately feet long with a chamber cross section of 3 feet by 3 feet.

Parts that are Difficult to

Maintain

Accessibility to various components and the time required to check and maintain them may justify coating. Hydraulic components in an industrial application experienced a 7-fold life increase through coating. Although the part was not expensive, nor was it manufactured in large volume, it was expensive to run maintenance on the part due to its inaccessible location.

5) Pollution Control Requirements The cathodic arc systems and the normal cleaning line requirements will not create pollution problems. The process utilizes the metal targets and a reactive gas (nitrogen, and oxygen) with no environmental hazards.

Applications for coatings are arising where standards are changing, such as:

* Use of poorer quality fuels (corrosion). Attachment C demonstrates an example of the corrosive protection of TiN coating generated with the cathodic arc.

* Tougher EPA emissions standards. These may result in closer tolerances and higher pressures to achieve improved sealing and reduce oil consumption. Existing coatings and substrate materials may not meet these demands.

* Tougher specifications on equipment to operate in abrasive atmospheres <sand, grit) and corrosive conditions (salt water, chemicals) along with extended maintenance cycles and life expectancy of the equipment. Hard coatings have demonstrated more than a 2-fold life increase on parts operating in an abrasive environment.

Coatings produced with the cathodic arc evaporation method range from metal films to nitrides and oxides. Alloys are also being utilized in this process as researchers develop unique variations for their specific applications. With the high ionization efficiency levels being produced with this technology, it appears that many combinations of materials and different reactive processes can be developed. Success similar to that experienced with the nitrides for hard coatings in the areas of adhesion» continuous films, and stoichiometry should be expected with these other materials.

Schematic of a Cathodic Arc Déposition System

Mechanical Properties of Zrt< end TIN Films Deposited by CAPD

Property zrn tin

Coefficient of friction O.CBO 0.035

ATTACHMENT " C "

Corrosion Protection Test

Material Tested - ^O-c stainless

Solutions tested - Ringers solution

Aqueous 0.5m NaCl yest - Anodic polarization

"One coating (cathodic arc) passivated at all potertialstested and dl®lay^ passivation current densities at least on order of magnitude less thai those of MK stainless steel which pitted,".

Corrosion Behavior of Thin Films Meletis, Carter, Hocftrm

ATTAQWENT " D "

Process

Ion Plating Arc Deposition

Sputtering

Characteristics of TIN Films Deposited by TTiree Techniques

Acteslon (kg)

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