Color of YSZ coating
06-12-2015, 11:01 AM,
#1
Color of YSZ coating
Dear forum members,
Recently I have carried out YSZ (PAC2008P) deposition with SG100 gun and to my surprise the color of the coating was complete grey and looking like NiCrAlY. Gun parameters are 800 A, Ar-45 LPM, H2-0.5 LPM, 30 KW, spray distance 70-80 mm. Literature study revealed the discoloration is due to colour centers in YSZ and ageing at 600 in normal air would solve the issue. I did the same and found the coating transformed from grey to cream yellow. XRD before and after showed same phase (tetragonal cubic ZrO2). Next day the same YSZ deposition without secondary H2 appeared white. Can anybody explain what parameters cud cause this? what shd be the color after plasma spray of YSZ? What are the deleterious effects of grey/white/cream yellow?

Regards
Vetri
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06-12-2015, 07:29 PM,
#2
RE: Color of YSZ coating
Hi Vetri
Color white from light cream color could be ok, the best coating without any oxidation will be quite white, this for the color, but the important thing is that all the technological test are inside the specification (metallographic and laboratory test) about grey color could be too much oxidation, maybe for the quality of H2 gas, or by air inside the gas net line for little pores on the welded tubes, or purity of the gas, I’ve never seen a gray color, maybe there is too much oxides, about gun SG100, I said in the past that this gun works well with only Ar, Ar/he, but do not perform well with Ar/H2
Best regards
Luigi
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06-14-2015, 08:37 PM,
#3
RE: Color of YSZ coating
(06-12-2015, 07:29 PM)loriolo Wrote: Hi Vetri
Color white from light cream color could be ok, the best coating without any oxidation will be quite white, this for the color, but the important thing is that all the technological test are inside the specification (metallographic and laboratory test) about grey color could be too much oxidation, maybe for the quality of H2 gas, or by air inside the gas net line for little pores on the welded tubes, or purity of the gas, I’ve never seen a gray color, maybe there is too much oxides, about gun SG100, I said in the past that this gun works well with only Ar, Ar/he, but do not perform well with Ar/H2

Hi Vetri,

The gray color is obtained when the substrate temperature is <170 - 200ºC.
When the substrate temperature is higher than the color becomes white.

Ion
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