the reason that cause the tearing ?
05-21-2013, 03:46 AM,
#1
the reason that cause the tearing ?
Hi all,
My MET result is not good when I spray METCO 81VF-NS ,is that tearing ? It JUST happened on both ends of the whole Field of View (FOV).
can anybody tell me the reason that happened ?
cutting ? temperature is not uniform when cooling or spraying or pre-heating ?



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05-21-2013, 12:16 PM,
#2
RE: the reason that cause the tearing ?
Hello!
The quality of coating look really horrible. Was it HVOF sprayed (as i would assume), but in that case it indicates high porosity?
It is hard to say from that image, but the bonding in coating looks pretty weak. Are those oxides on the border between coating and substrate?
This also does not look as a typical cracking, again more like bonding/oxidation problems.





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05-21-2013, 02:53 PM,
#3
RE: the reason that cause the tearing ?
I have different view of this coating. It looks like the lab preparation is bad, cutting sometimes make the coating crack and the picture looks like they over polish the coating. Please make sure the lab cut start from coating to substrate, using different mounting material and reduce the heat up rate will help.
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05-21-2013, 04:40 PM,
#4
RE: the reason that cause the tearing ?
(05-21-2013, 02:53 PM)derek Wrote: I have different view of this coating. It looks like the lab preparation is bad, cutting sometimes make the coating crack and the picture looks like they over polish the coating. Please make sure the lab cut start from coating to substrate, using different mounting material and reduce the heat up rate will help.

I do agree that the preparation of this coating is bad. Not a question. And it is over grounded and polished. This can explain the porosity and in most cases cracking, but not the bonding defects...
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