I have a stage 1 bucket with a PtAl bond coat on the aerofoil.
We applied a EB-PVD Thermal barrier coat to the aerofoil which spalled. The shank and root of the bucket did not have any PtAl or PVD which we wanted, although there was a green colour to the uncoated regions.
We stripped the PVD using KOH strip, washed the bucket until the solution was at a neutral PH.
A blast was performed.
A heat tint was perfromed at 700 degrees
The aerfoil was gold - as expected
The root and shank of the bucket was also gold- this should have been blue due to the presence of no coating.
My question is : could the KOH strip be the reason for the gold appearance?
Or is the green discolouration from the PVD a more possible reason.
i would apprecitate any help!
We applied a EB-PVD Thermal barrier coat to the aerofoil which spalled. The shank and root of the bucket did not have any PtAl or PVD which we wanted, although there was a green colour to the uncoated regions.
We stripped the PVD using KOH strip, washed the bucket until the solution was at a neutral PH.
A blast was performed.
A heat tint was perfromed at 700 degrees
The aerfoil was gold - as expected
The root and shank of the bucket was also gold- this should have been blue due to the presence of no coating.
My question is : could the KOH strip be the reason for the gold appearance?
Or is the green discolouration from the PVD a more possible reason.
i would apprecitate any help!
