Problem solved CM1 Plasma coating for MAN
11-17-2015, 04:55 AM,
CM1 Plasma coating for MAN
Dear Experts,

I met problem for CM1 Plasma coating for MAN specification, MAN require no crack in coating and bond area of Cr3C2-NiCr blend with Mo coating for piston ring when load 5,10,20 kg testing, even adjusted spray parameters many times, but crack happen in bond area and coating, anyone has related experience to share will be great appreciate.

11-17-2015, 08:58 AM,
RE: CM1 Plasma coating for MAN
Hi plzc126330,

It is difficult to find a reason without images (cross sections). But something can be understood:

1) 5, 10 and 20 kg after MAN specification (Brinell test of interfaces) mean very different loads. 5 kg need really all layers without cracks endure, 10 kg is a limit, the "bad" and "good" layers separating. 20 kg survive only the best layers without cracks.

2) When vertical cracks produced in the layer after the test, it suggests to high tensile stresses in the layer.

3) If the layer still exhibits no cracks after the test, but detached from the substrate, the adhesion is too low.

Give some more info and pictures, then we can talk about causes and necessary measures.


11-17-2015, 12:28 PM,
RE: CM1 Plasma coating for MAN
Hi plzc126330,

I agree with Vadim that you need to provide some more information. Otherwise it will be impossible to give an advice which makes any sense at all!

1. Please share some metallographic and some other pictures of the cracks.
2. What process are you using (plasma, hvof)?
3. Which plasma gun and gasses?
4. Which HVOF gun and which fuel/gasses?
5. What is the grain size of the powders used?
6. What is the blend ratio and how do you mix it?

If you provide this data we can give a better advise on how to solve it.


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