time and temperature adequate to assure u201c burn off u201d of any of the cutting lubricants used in the machining process typically 2 hrs 700 u00b0 f but is lubricant dependent the key is getting the erosion resistant coating 24 to bond to the frcmc structure 14 if the surface of the frcmc structure 14 is not properly prepared the erosion resistant coating 24 can simply flake off and provide no long term protection in the preferred approach depicted in fig5 the surface of the frcmc structure 14 is lightly grit blasted to form small divots 26 within the ceramic matrix of the frcmc structure 14 it is also believed that the light grit blasting exposes hairs or whiskers on the exposed fiber of the generic fiber system which the erosion resistant coating 24 can grip and adhere thereto typical grit blasting that has proved successful is 100 grit 20 psi according to a second possible approach the surface of the frcmc structure 14 can be provided with a series of thin shallow regularly spaced grooves 28 similar to fine u201c threads u201d of a nut or bolt as depicted in fig6 which the erosion resistant coating 24 can mechanical lock into essentially the surface is scored to provide a roughened surface instead of a smooth surface the depth width and spacing of the grooves 28 is not critical and can be determined for each part or component without undue experimentation in general the grooves 28 should be closely spaced so as to minimize any large smooth areas of the surface where there is a potential for the erosion resistant coating 24 to lose its adhesion and flake off thus over grooving would be preferable to under grooving.