How to polish Zr2O3 coating to Ra3.2

[stvon]

Dear everyone
Does anybody know what's the procedure to make APS Zr2O3 coating with roughness of Ra3.2 um ? And how to protect cooling hole of parts during spraying?

[loriolo]

Hi Stvon
The roughness you ask for is not so smooth, you ask for a coating with roughness of Ra 3.2 µm, so it'is enough to use a diamond grinding wheel Grit Size C150 / 6,6 ct/mm3 , and in order to protect the cooling holes of parts during spraying, you can use a graphite (or sometime Cu) pin wedge with the appropriate dimensions.

Formulas for determining minimum stock removal required on diameter to achieve desired surface finish are as follow:

Surface Finish in Micrometers-(µm) Ra
(Existing Finish - Desired Finish) /100 = Required Stock Removal

Example:
Existing Finish = 5.25 µm; Desiderated Finish = 3.25 µm

(5.25 – 3.25) /100 =0.02 mm