Hi Justin
Quote:Excuse me.
I'm not sure that I understand what you mentioned.
Do you mean that grinding/polishing may result in the appearance of the bigger voids?
Sorry, what I'm trying to say, is that preparation for metallography can cause pull-outs, which can make porosity look worse than it actually is. On the other hand smearing can have the opposite effect. So make sure you are confident in your metallographic results before making parameter changes.
Quote:Is it useless to decrease the bigger voids by adjusting the thermal spray parameters?
No, I think most coatings could be improved through good coating development work. It just takes time and effort which can be costly. It is difficult to judge the quality of your coating without first hand knowledge and experience with your specific powder and process, but if this is the worst case, I don't think it is too bad.