I have experience in replacing high temperature metal nozzles with plastic materials. They offer superior wear to say stainless, but the temperaure limitations are around
500 degrees F. I would suggest a bearing grade of Ryton, PEEK or Polyimide all have
tensile's of 15,000 to 35,000 psi.

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Good Luck

You didn't indicate what your operating temperature is.  If it is below 1000 F, have you considered a carbidic grey iron?  Chromium alloyed gray iron can develop considerable carbide content (10-25%) which has excellent wear resistance.   CWC produces a material they call proferal or super proferal that is used for engine camshafts. I would think such a material would provide substantial improvement over 310 stainless.

The better materials for nozzles at high temp. and abrasion are made with silicium carbide, silicium nitride or mix of the two.Ask to makers of ceramic kilns.