Erosion Test of an Abradable Coating |
02-10-2014, 10:25 AM
Post: #1
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Erosion Test of an Abradable Coating
Dear All,
We are spraying 60:40 Ni/Graphite over Metco 450NS via flame spraying. Top coat thickness is within .060-.070". As you know this powder combination is an abradable coating and there is an erosion test reqirement which I should verify and we couldn’t have managed so far. My question is about this requirement. The erosion rate requirement is in terms of sec/mil (max 9 sec/mil) but, I am a little bit over that requirement (11 sec/mil). I suppose I can lower this value by decreasing hardness (Hardness checks 70 HR15Y). Is this correct? *Erosion rate: time to deplete a specific amount of grit media/depth of erosion Technical Info: We’re using a 6P-II gun with a 6PT-II-1 extension module and spraying at an angle of 80 degrees. System consists of oxygen, acetylene and Argon as carrier gas. I can not change pressure values due to possible risk of alterations at other coatings. Flow values are as follows (nlpm): -Oxygen: 14 -Acetlyene: 14 -Argon: 3.5 Spray rate: 55 gr/sec Would you please advice if I should increase the spray rate or change the flow values? Or any other ideas? Thank you very much. | |||
02-10-2014, 02:50 PM
Post: #2
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RE: Erosion Test of an Abradable Coating
Hi baaddin
![]() Change oxygen and fuel gas flows equally. Decreasing flow will make coating softer. Keep all other parameters constant. A HR15Y hardness of around 50 should give you the desired result. Regards Gordon www.gordonengland.co.uk www.surfaceengineer.co.uk Photography Obsession | |||
02-10-2014, 08:50 PM
Post: #3
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RE: Erosion Test of an Abradable Coating
Look for what I call spider webbing between the nickel in the microstructure. It is a good indication of your temperature and it greatly affects the erosivity. No spider webbing and you get a low erosivity value high spider webbing you get a high value. Drop the temperature until less spider webbing is present and then chech the erosivity value.
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02-11-2014, 07:32 AM
Post: #4
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RE: Erosion Test of an Abradable Coating
Thank you all for the recommendations. I'm going to start the trials today and will share the results.
Regards, | |||
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