porosity problem
12-19-2011, 04:36 AM,
#1
porosity problem
hi all
we are using 9mb gun we are trying to coat pac127(72F NS) we are getting the porosity around 26% we are yousing the recommended parameter by powder alloy corporation and the metco parameters also but we are not getting the dense coating.
please any body give me the solution we have coated the almost 8samples for metalography almost all the samples are appearing the same porosity.
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12-23-2011, 04:58 AM,
#2
RE: porosity problem
with the starting paramaters for 72f you should be around 10% max. People can get it down to less then 2%. You must not be following your paramaters or the equipment needs to be calibarated.
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12-23-2011, 02:24 PM,
#3
RE: porosity problem
Hi srihan_1

Sign0016 to the Surface Engineering Forum.

Agree with kschewe's comments, though you could be having problems with your metallography giving false results due to grinding/polishing artifacts (pull-outs).
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12-23-2011, 05:32 PM,
#4
RE: porosity problem
I went through this same problem last month. The polish technique has a big influance on this issue. What spray parameters are you using?
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09-12-2013, 02:40 AM,
#5
RE: porosity problem
What's the distance that you are using? I've had that problem before, and reducing the distance is one of the way that seems to work for me.
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09-17-2013, 01:09 PM,
#6
RE: porosity problem
(12-23-2011, 05:32 PM)Chico Wrote: I went through this same problem last month. The polish technique has a big influance on this issue. What spray parameters are you using?

I agree with Chico, polishing is a huge problem with this material as it is prone to "pulling out". Are you vacuum impregnating the sample or hot mounting?
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09-30-2013, 08:12 PM,
#7
RE: porosity problem
(09-17-2013, 01:09 PM)ServiceTech Wrote:
(12-23-2011, 05:32 PM)Chico Wrote: I went through this same problem last month. The polish technique has a big influance on this issue. What spray parameters are you using?

I agree with Chico, polishing is a huge problem with this material as it is prone to "pulling out". Are you vacuum impregnating the sample or hot mounting?

The coating should be easy to spray but polishing it a little different from the usual polishes. The lab has to have had some experience with this coating and has to know two things. It does not like grit paper sizes finer than 600 and it requires a long polish time (15 min)
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