Diamond Like Carbon

[Big Tea]

Anyone with an interest in this may like this
and the follow on next Wednesday.

He has a slight speech impediment, but CC is available if you have trouble.

It is mostly glossing through and twice as long as it needs to be but prob still worth the 20 min

[TimW]

It's been very common on f1 cam shafts as well.
The nicest thing about it is that it's harder than most low friction coatings, even Ti nitride. The hardness of the coating only gets you so far, the rest of the system has to be well engineered too.

Do these coatings change the material hardness significantly? I would have thought the hardness would be more a function of the base material since the nano coatings are so thin.

Depends on the scale (scale as in size) you are measuring on. Micro scale hardness will increase dramatically (e.g. scratch resistance), but large scale hardness would hardly be affected (so same as base material hardness,
hammer would leave same size dent).

I guess exactly as you thought it would be.

[Andres125sx]

Anyone with an interest in this may like this

Indeed, very good video explaining everything, from composition to current problems and aplications

[Cold Fussion]

It's been very common on f1 cam shafts as well.
The nicest thing about it is that it's harder than most low friction coatings, even Ti nitride. The hardness of the coating only gets you so far, the rest of the system has to be well engineered too.

Do these coatings change the material hardness significantly? I would have thought the hardness would be more a function of the base material since the nano coatings are so thin.

Depends on the scale (scale as in size) you are measuring on. Micro scale hardness will increase dramatically (e.g. scratch resistance), but large scale hardness would hardly be affected (so same as base material hardness,
hammer would leave same size dent).

I guess exactly as you thought it would be.

That makes sense, thanks.

[strad]

Wear factor is what I would be concerned with and the slipperiness . The mentioned Teflon impregnated pistons were like wet ice on wet ice.

[humble sabot]

Do these coatings change the material hardness significantly? I would have thought the hardness would be more a function of the base material since the nano coatings are so thin.

Surface hardness,specifically.
On high wear, but low load cases, like a cylinder wall, using a hard coating on relatively soft aluminium pistons or bores is fine, but when you have strong eccentric moments, like a camshaft or a crankshaft, the base material has to have a higher base surface hardness to support the surface treatment. If not it'll simply flake off, or be pushed into the surface.