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the first base coating used to reduce wear and galling from reduced friction, increased harness, and increased lubricity of parts: electrolytic chromium plating.

with chromium plating on camshafts and pneumatic tappet rockers in today's formula 1 engines that rev at 19,200 rpm, the cams and rockers would last something like 10 min. max.

PVD = Physical Vapor Deposition Coating

in a vacuum (10-15 bar) chamber the deburred and demagnetized part to be coated (eg. valves or retainers) is heated by an electron beam to 350-450 degrees Celcius and a vapor of either titanium or nickel or steel alloy evaporates (1-4 microns thick) onto the surface of the item. The electron beam's negative charge attracts the vaporized alloy onto the surface of the part.

Titanium nitride is most common PVD hard coating to prevent galling in lightly loaded parts. It has a lower friction coefficient and higher hardness than chromium.

For highly loaded parts 2 separate layers of coatings is needed one with titanium nitride and the other containing an aluminum & vanadium alloy. This extra hard layer resists abrasions and sliding wear (eg. clutch disc).

PVD + CVD (chemical vapor deposition) Coating


This combines the charging of the part with electrons (from a beam) with a chemical reaction to induce the deposition of the coating material.

Another name for this process is Plasma Assisted Chemical Vapor Deposition (PACVD). A plasma layer is created when they combine an electron beam with a chemical reaction on the surface.

This is the newest process you see in coating technology these days and it's only seen at the level of formula 1. PACVD coating process is used to create something called a DIAMoND LIKE COATING (DLC) (i.e. as hard as a diamond) made of carbon and hydrogen in diamond lattice structure or a carbon graphite structure. These are about 3-5 microns thick. These are what the F1 teams are using on their cams and rockers that rev to 19,200 rpm.

How is this related to us?

When you decide to shop for valvesprings, cams, retainers, spring seats, valves and rockers and you are looking for extra longterm protection, PVD coating your valvetrain components is a consideration. It may help you valvetrain last longer (increased hardness, less wear, and galling) and run cooler with less friction (increased lubricity to allow the oil to cling to it better).

We should try to identify companies who can coat these parts at a competitive price.
 

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Great info, MD.
Are the Swain coatings similar or do you know any tech on their applications and effectiveness?
Thanks.
 

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That seems intresting, but do you have an idea as to how much PVD costs as compared to cryofreezing something? Supposedly cryogenicly freezing the same components, they have been shown to last longer and wear less. And it's pretty cheap too.
 
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