abradable coating failure
08-24-2015, 01:46 PM, (This post was last modified: 08-24-2015, 02:01 PM by stvon.)
#1
abradable coating failure
Dear all

I encounter a abradable coating failure(some top coating peeled off ) but didn't know why, please see attachment. Can you guys tell me what's the reason and what should I do to prevent it happen again.

   
Reply
08-25-2015, 09:17 AM,
#2
RE: abradable coating failure
(08-24-2015, 01:46 PM)stvon Wrote: Dear all

I encounter a abradable coating failure(some top coating peeled off ) but didn't know why, please see attachment. Can you guys tell me what's the reason and what should I do to prevent it happen again.

Hello,
Could you please confirm what bond and top coat you applied?
What is the base material and dimensions coated?
Thanks
Cheers
Reply
08-26-2015, 10:27 AM,
#3
RE: abradable coating failure
(08-25-2015, 09:17 AM)Laurent Wrote:
(08-24-2015, 01:46 PM)stvon Wrote: Dear all

I encounter a abradable coating failure(some top coating peeled off ) but didn't know why, please see attachment. Can you guys tell me what's the reason and what should I do to prevent it happen again.

Hello,
Could you please confirm what bond and top coat you applied?
What is the base material and dimensions coated?
Thanks
Cheers
Bond coating is Metco 450NS, top coating is Nickel Chromium Aluminum Nickel Graphite, and base material is similar to Incoloy 907 of a compressor case.
Reply
08-28-2015, 07:52 AM,
#4
RE: abradable coating failure
(08-26-2015, 10:27 AM)stvon Wrote:
(08-25-2015, 09:17 AM)Laurent Wrote:
(08-24-2015, 01:46 PM)stvon Wrote: Dear all

I encounter a abradable coating failure(some top coating peeled off ) but didn't know why, please see attachment. Can you guys tell me what's the reason and what should I do to prevent it happen again.

Hello,
Could you please confirm what bond and top coat you applied?
What is the base material and dimensions coated?
Thanks
Cheers
Bond coating is Metco 450NS, top coating is Nickel Chromium Aluminum Nickel Graphite, and base material is similar to Incoloy 907 of a compressor case.

Hi Stvon,
Bond coat should be ok whether base material has been properly prepared (degreasing, sand blasting).
There are two major causes we analyzed recently to address similar peeling off of top coat (320NS or 601NS) on shroud case and air inlet housing.
#1
We modified grit mesh from 50-60 down to 20-30, not below as sand blast becomes shot peening.
#2
Operator didn't take enough care of surface preparation prior to sand blasting. There were residuals of FPI revelator onto base material surface (using black light).
We introduced a cleaning op just before masking and sand blasting.

Both mods lead to a much better peeling test.

Note: base metals are aluminium and inco.

Hope it helps
cheers
Reply
10-19-2015, 04:52 PM, (This post was last modified: 10-19-2015, 04:56 PM by Johnny_Blaze.)
#5
RE: abradable coating failure
(08-24-2015, 01:46 PM)stvon Wrote: Dear all

I encounter a abradable coating failure(some top coating peeled off ) but didn't know why, please see attachment. Can you guys tell me what's the reason and what should I do to prevent it happen again.

Hi stvon,
I'm not sure if you found a solution yet?

It would be good to know which hardware and parameters were used, hardness of the coating prior to putting the component into service, and, duration in service before failure.

John.


(08-28-2015, 07:52 AM)Laurent Wrote:
(08-26-2015, 10:27 AM)stvon Wrote:
(08-25-2015, 09:17 AM)Laurent Wrote:
(08-24-2015, 01:46 PM)stvon Wrote: Dear all

I encounter a abradable coating failure(some top coating peeled off ) but didn't know why, please see attachment. Can you guys tell me what's the reason and what should I do to prevent it happen again.

Hello,
Could you please confirm what bond and top coat you applied?
What is the base material and dimensions coated?
Thanks
Cheers
Bond coating is Metco 450NS, top coating is Nickel Chromium Aluminum Nickel Graphite, and base material is similar to Incoloy 907 of a compressor case.

Hi Stvon,
Bond coat should be ok whether base material has been properly prepared (degreasing, sand blasting).
There are two major causes we analyzed recently to address similar peeling off of top coat (320NS or 601NS) on shroud case and air inlet housing.
#1
We modified grit mesh from 50-60 down to 20-30, not below as sand blast becomes shot peening.
#2
Operator didn't take enough care of surface preparation prior to sand blasting. There were residuals of FPI revelator onto base material surface (using black light).
We introduced a cleaning op just before masking and sand blasting.

Both mods lead to a much better peeling test.

Note: base metals are aluminium and inco.

Hope it helps
cheers


Greetings Laurent,
Can you give more feedback on some of the failures and causes of failures you have experienced with 320NS and 601NS?

Cheers,
John
Reply
10-20-2015, 02:29 PM,
#6
RE: abradable coating failure
(10-19-2015, 04:52 PM)Johnny_Blaze Wrote:
(08-24-2015, 01:46 PM)stvon Wrote: Dear all

I encounter a abradable coating failure(some top coating peeled off ) but didn't know why, please see attachment. Can you guys tell me what's the reason and what should I do to prevent it happen again.

Hi stvon,
I'm not sure if you found a solution yet?

It would be good to know which hardware and parameters were used, hardness of the coating prior to putting the component into service, and, duration in service before failure.

John.


(08-28-2015, 07:52 AM)Laurent Wrote:
(08-26-2015, 10:27 AM)stvon Wrote:
(08-25-2015, 09:17 AM)Laurent Wrote:
(08-24-2015, 01:46 PM)stvon Wrote: Dear all

I encounter a abradable coating failure(some top coating peeled off ) but didn't know why, please see attachment. Can you guys tell me what's the reason and what should I do to prevent it happen again.

Hello,
Could you please confirm what bond and top coat you applied?
What is the base material and dimensions coated?
Thanks
Cheers
Bond coating is Metco 450NS, top coating is Nickel Chromium Aluminum Nickel Graphite, and base material is similar to Incoloy 907 of a compressor case.

Hi Stvon,
Bond coat should be ok whether base material has been properly prepared (degreasing, sand blasting).
There are two major causes we analyzed recently to address similar peeling off of top coat (320NS or 601NS) on shroud case and air inlet housing.
#1
We modified grit mesh from 50-60 down to 20-30, not below as sand blast becomes shot peening.
#2
Operator didn't take enough care of surface preparation prior to sand blasting. There were residuals of FPI revelator onto base material surface (using black light).
We introduced a cleaning op just before masking and sand blasting.

Both mods lead to a much better peeling test.

Note: base metals are aluminium and inco.

Hope it helps
cheers


Greetings Laurent,
Can you give more feedback on some of the failures and causes of failures you have experienced with 320NS and 601NS?

Cheers,
John

Hi John,
Major failure was top coat that peeled off ( same as Stvon picture)
450NS bond was ok, but top coat only peeled off.
Thanks
Reply
10-21-2015, 11:10 PM,
#7
RE: abradable coating failure
(10-20-2015, 02:29 PM)Laurent Wrote:
(10-19-2015, 04:52 PM)Johnny_Blaze Wrote:
(08-24-2015, 01:46 PM)stvon Wrote: Dear all

I encounter a abradable coating failure(some top coating peeled off ) but didn't know why, please see attachment. Can you guys tell me what's the reason and what should I do to prevent it happen again.

Hi stvon,
I'm not sure if you found a solution yet?

It would be good to know which hardware and parameters were used, hardness of the coating prior to putting the component into service, and, duration in service before failure.

John.


(08-28-2015, 07:52 AM)Laurent Wrote:
(08-26-2015, 10:27 AM)stvon Wrote:
(08-25-2015, 09:17 AM)Laurent Wrote: Hello,
Could you please confirm what bond and top coat you applied?
What is the base material and dimensions coated?
Thanks
Cheers
Bond coating is Metco 450NS, top coating is Nickel Chromium Aluminum Nickel Graphite, and base material is similar to Incoloy 907 of a compressor case.

Hi Stvon,
Bond coat should be ok whether base material has been properly prepared (degreasing, sand blasting).
There are two major causes we analyzed recently to address similar peeling off of top coat (320NS or 601NS) on shroud case and air inlet housing.
#1
We modified grit mesh from 50-60 down to 20-30, not below as sand blast becomes shot peening.
#2
Operator didn't take enough care of surface preparation prior to sand blasting. There were residuals of FPI revelator onto base material surface (using black light).
We introduced a cleaning op just before masking and sand blasting.

Both mods lead to a much better peeling test.

Note: base metals are aluminium and inco.

Hope it helps
cheers


Greetings Laurent,
Can you give more feedback on some of the failures and causes of failures you have experienced with 320NS and 601NS?

Cheers,
John

Hi John,
Major failure was top coat that peeled off ( same as Stvon picture)
450NS bond was ok, but top coat only peeled off.
Thanks


Thanks for the response Laurent,
Do you happen to know what the hardness value was, if your problem was more specifically related to M320NS?

John
Reply
10-23-2015, 01:02 PM,
#8
RE: abradable coating failure
(10-21-2015, 11:10 PM)Johnny_Blaze Wrote:
(10-20-2015, 02:29 PM)Laurent Wrote:
(10-19-2015, 04:52 PM)Johnny_Blaze Wrote:
(08-24-2015, 01:46 PM)stvon Wrote: Dear all

I encounter a abradable coating failure(some top coating peeled off ) but didn't know why, please see attachment. Can you guys tell me what's the reason and what should I do to prevent it happen again.

Hi stvon,
I'm not sure if you found a solution yet?

It would be good to know which hardware and parameters were used, hardness of the coating prior to putting the component into service, and, duration in service before failure.

John.


(08-28-2015, 07:52 AM)Laurent Wrote:
(08-26-2015, 10:27 AM)stvon Wrote: Bond coating is Metco 450NS, top coating is Nickel Chromium Aluminum Nickel Graphite, and base material is similar to Incoloy 907 of a compressor case.

Hi Stvon,
Bond coat should be ok whether base material has been properly prepared (degreasing, sand blasting).
There are two major causes we analyzed recently to address similar peeling off of top coat (320NS or 601NS) on shroud case and air inlet housing.
#1
We modified grit mesh from 50-60 down to 20-30, not below as sand blast becomes shot peening.
#2
Operator didn't take enough care of surface preparation prior to sand blasting. There were residuals of FPI revelator onto base material surface (using black light).
We introduced a cleaning op just before masking and sand blasting.

Both mods lead to a much better peeling test.

Note: base metals are aluminium and inco.

Hope it helps
cheers


Greetings Laurent,
Can you give more feedback on some of the failures and causes of failures you have experienced with 320NS and 601NS?

Cheers,
John

Hi John,
Major failure was top coat that peeled off ( same as Stvon picture)
450NS bond was ok, but top coat only peeled off.
Thanks


Thanks for the response Laurent,
Do you happen to know what the hardness value was, if your problem was more specifically related to M320NS?

John

Hi John,
Hardness was of : HR 15Y 55 to 70
we were at an average of 65.72, so within tolérances
Cheers
Thanks
Laurent
Reply
11-08-2015, 03:52 AM,
#9
RE: abradable coating failure
(10-23-2015, 01:02 PM)Laurent Wrote: Hi John,
Major failure was top coat that peeled off ( same as Stvon picture)
450NS bond was ok, but top coat only peeled off.
Thanks

Quote:Thanks for the response Laurent,
Do you happen to know what the hardness value was, if your problem was more specifically related to M320NS?

John

Quote:Hi John,
Hardness was of : HR 15Y 55 to 70
we were at an average of 65.72, so within tolérances
Cheers
Thanks
Laurent

M320NS is not one of the better choices, but clearly Stvon's picture clearly defines problems with spraying technique and post-spraying operations that compromised the integrity of the coating...what other post plasma spray operations are taking place before placing the component(s) back into service?

Regards,
John

Reply
11-11-2015, 05:21 PM,
#10
RE: abradable coating failure
(11-08-2015, 03:52 AM)Johnny_Blaze Wrote:
(10-23-2015, 01:02 PM)Laurent Wrote: Hi John,
Major failure was top coat that peeled off ( same as Stvon picture)
450NS bond was ok, but top coat only peeled off.
Thanks

Quote:Thanks for the response Laurent,
Do you happen to know what the hardness value was, if your problem was more specifically related to M320NS?

John

Quote:Hi John,
Hardness was of : HR 15Y 55 to 70
we were at an average of 65.72, so within tolérances
Cheers
Thanks
Laurent

M320NS is not one of the better choices, but clearly Stvon's picture clearly defines problems with spraying technique and post-spraying operations that compromised the integrity of the coating...what other post plasma spray operations are taking place before placing the component(s) back into service?

Regards,
John

HI,

Quick question...what temperature are you holding the part to while spraying? Abradables like to stay relatively hot between cycles. If you are cooling too much between cycles you could get layering, thus possibly causing separation between the layers of coating. Are you spraying one part at a time or several parts in a fixture? I've found that the best temperature to maintain is around 200 - 225 deg. F. I use a traverse rate of 4 mm/sec with both 314ns (6P combustion gun) and 320ns (3mb spray gun) powders, which I have found to be the best traverse to help maintain part temp and get an even distribution of coating onto an I.D. face. Also, low table rpms help to maintain part temp. Somewhere around 100 rpms seems to work well.

Mike
Reply
11-16-2015, 09:16 PM,
#11
RE: abradable coating failure
Quote:HI,

Quick question...what temperature are you holding the part to while spraying? Abradables like to stay relatively hot between cycles. If you are cooling too much between cycles you could get layering, thus possibly causing separation between the layers of coating. Are you spraying one part at a time or several parts in a fixture? I've found that the best temperature to maintain is around 200 - 225 deg. F. I use a traverse rate of 4 mm/sec with both 314ns (6P combustion gun) and 320ns (3mb spray gun) powders, which I have found to be the best traverse to help maintain part temp and get an even distribution of coating onto an I.D. face. Also, low table rpms help to maintain part temp. Somewhere around 100 rpms seems to work well.

Mike

It is important to note that your traverse and surface speed values only apply to your part. Different diameters could change these numbers considerably. Metco has specs, in some cases, that define the typical traverse rate per revolution, such as 0.125"-0.250", which can then be calculated based on the surface speed of the part (diameter and RPM calculation)
Part diameter (inches): X
Part circumference (ft): (X*3.1415927)/12
Surface speed (ft per min): Y (such as 100-300SFPM)
RPM: Y/part circumference
Traverse/Increment per Rev: Z" (in inches)

Travers speed:
TS (in/min): Z*RPM
TS (mm/sec): Z*RPM*0.42333
Reply
11-17-2015, 12:33 PM,
#12
RE: abradable coating failure
I think this is sprayed by hand right?

Most likely the following occurred:

1. thickness per pass too high, move faster turn faster!
2. powder flow not stable (pulsing) which causes large amounts of particles to get not enough heat and semi-molten. (inject less material, higher carrier gas, adjust powder feeder itself)
3. not enough cooling air to blow dust away and cool part down. (ad air jets)

good luck,
Joris
Reply




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