Wear surfaces / Surface Hardness?
Wear surfaces / Surface Hardness?
(OP)
I have a question regarding surface hardness. I have a rotary actuator that pushes a flat plate against a stop. During the pushing a small amount of sliding takes place, due to the design. I am seeing wear after about 100k cycles. I currently have both pieces as hard coat anodize on aluminum. So they are both the same hardness. What materials or platings would provide a longer life without visable wear?
In general is it better to have one material harder than the other? by how much?
Thanks,
Bill
In general is it better to have one material harder than the other? by how much?
Thanks,
Bill





RE: Wear surfaces / Surface Hardness?
RE: Wear surfaces / Surface Hardness?
Alum. against alum. is usually especially bad-I think the hard anod. is saving you.
Kenvlach can provide good info on electroless Ni coating-dunno how it works w/ alum, but he will.
RE: Wear surfaces / Surface Hardness?
http://www.microplasmic.com
http://www.keronite.com
You also may want to consider Diamond-Like Coatings. One DLC supplier I can recommend is Diamonex. You can find more information at:
http://www.diamonex.com
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Wear surfaces / Surface Hardness?
Thanks,
Bill
RE: Wear surfaces / Surface Hardness?
In any case, you'd need to test it well first.
RE: Wear surfaces / Surface Hardness?
lubricant? If you cannot use conventional lubricants, then I have 2 alternatives:
One approach would be to have the hard anodize (unsealed) impregnated/coated with a PTFE-containing dryfilm lubricant.
There are 3 grades, from simple dip + air dry to a baked on coating with phenolic (or other thermosetting resin) binder.
See MIL-A-63576A, which can be downloaded from the DoD's ASSIST site:
http://assist2.daps.dla.mil/eAccess/index.cfm?ident_number=31464
Another approach would be electroless nickel containing co-deposited PTFE particles:
"Composite Coatings: These types of coatings are specifically designed to enhance or improve the wear resistance properties for numerous applications. Co-deposits are chosen for frictional wear conditions and also heavy load wear conditions. Depending upon the type of co-deposit, composite coatings offer a wide variety of options for meeting specific demands.
Niklad Nilon: A unique Teflon dispersion blend that provides a 18 to 26 % v/v nickel Teflon co-deposit. The system produces the highest Teflon co-deposit, which is favored for frictional, low load wear environments.
Elnic 121 TF: A Teflon dispersion blend that provides a 10 to 20 % v/v nickel Teflon co-deposit. The advantage of lower Teflon co-deposits is the excellent coating performance under frictional wear and heavier loads. This condition is more representative in most applications today.
Niklad Dispersant: Utilized to enhance the co-deposition of diamonds, boron nitride, silicon carbide or other similar particles into an electroless nickel phosphorus deposit matrix."
The above info is from MacDermid;
http://www.macindustrialproducts.com/enproducts.html
other EN suppliers like Atotech have similar products.
RE: Wear surfaces / Surface Hardness?
If this is not a problem, then you're free to try different combinations with consideration for wear-resistance, lubricity, and anti-galling (hard/soft combinations are often used precisely to avoid galling because the materials will be dissimilar).
RE: Wear surfaces / Surface Hardness?
With hard particles present, the use of one soft surface allows the particles to imbed easily, and they don't usually score the harder surface-eg, journal bearings.
RE: Wear surfaces / Surface Hardness?
Thanks,
Bill
RE: Wear surfaces / Surface Hardness?
More information regarding MoSTâ„¢ and carbon based coatings is available from http://www.teercoatings.co.uk
PVD theory is available from
http://www.pvd-coatings.co.uk
RE: Wear surfaces / Surface Hardness?
RE: Wear surfaces / Surface Hardness?
RE: Wear surfaces / Surface Hardness?
Thanks all for the input. I'm going with A anodized Hardcoat Rc65 on one surface and a Polyond ( Teflon impregnated Nickel) Rc55/60 on the other. I'll post the results when I know.
Thanks Again
Bill