High porosity in WcCoCr

[demionkrishan]

Team,
PFA image , I have no clue, why too high. Usually i used to get below 1%
Of porosity. Can you guys? Support me to rectify this issue as possible.
Regards
Krishz

[velocity]

Team,
PFA image , I have no clue, why too high. Usually i used to get below 1%
Of porosity. Can you guys? Support me to rectify this issue as possible.
Regards
Krishz

First check blasting media. If its clean check air. If its dry, your compressor drier works fine so it means your spraying air is also dry so check surface porosity. Some materials sucks dirt or lubricant, especially cast alloys. Clean with flame. If its not enough, 1 layer arc spray buffer would be better.
Furnace powder and be sure it is dry too. Maybe it has humid.
I hope you can figure it out without trying all

[demionkrishan]

Thanks, Velocity. I have failed thrice. used JP8000, 5220 TAFA HVOF with the below parameters. oxygen - 2000 fuel 6 spray rate - 76g/min 4" barrel spray distance - 14"
combustion pressure -105-108 carrier-23
Powder - WOKA-3652 (86104)

Sample looks fine after pre grounded,
Bond strength - 13500 psi
Hardness 63HRC
Corrosion test - pass
dry rubber test - pass
Surface finish 0.05- 0.09
Thickness- =8-10 mils
porosity - 1.6 % -3 % (not with in p limit)
please find the attached images


Still, I couldn't able to solve the porosity issue, if someone able to guide will be most helpful.

[demionkrishan]

PFA image

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2nd test PFA

[loriolo]

Hi Krishz
I see, you have some problem in the interface too and, maybe there is some dirties inside the spray cabin with too much turbulences, or if you get better result before this test, the only think could be changed is powder quality, try with other powder supplier, time ago I had a lot of problem with 105 NS powder and it was enough to change the supplier.