Hi Gordon and everyone,

Today, two of my colleagues consider that different configurations (different nozzles and powder feed port etc.) for the same spray gun can be adopted to spray the same coating. For example, both of 732 and 733 nozzles of 9MB spray gun can be used to spray the Polyester-AlSi abradable coating very well if the spray parameters have been optimized for this or other coatings.

I wonder if their views as stated above is right. I have believed that 733 nozzle is the best, well 732 nozzle is not suitable to spray the Polyester-AlSi coating.

Hi Fhyuan

To some extent this is true, but you need to be careful in what you consider "the same coating" to be. An example would be a fine chromium oxide powder that we use to spray, with a choice of two parameter sets. One using a wide bore 732 nozzle, the other a 733 narrow bore. Two very good coatings, but the "733" produced very slightly denser and harder coatings, but the "732" provided 45% deposit efficiency as apposed to 20% of the "733".

Not tried this with Polyester-AlSi though, I would have concerns about producing the same % coating phase mix and hardness.Tricky balance in getting the right conditions for both polyester and AlSi alloy right, all to easy to burn polyester in lower velocity plasma.

hello all
if there are different nozzles,there are different size of powder,may be it s the raison
but i don t know