Response frequency spectrum analysis for impact behavior assessment of surface materials

We report a method for surface status assessment, which is based on spectrum analysis of impact response frequency. Impact behavior of 2Cr13 (AISI-420) stainless steel bulk material, plasma-sprayed Cr2O3 ceramic coating and flame-sprayed NiCrBSi alloy coatings were investigated. By using a specifically designed impact tester and its attached measuring system, time domain signals and frequency signals in the course of impact were recorded and analyzed. Both single impact mode with different energies and repetitive impact mode were applied. Surface morphologies after impact were observed. The results showed a significant interrelationship between the impact effect and the characteristics of the response frequency spectrum. Changes occurring in the material surface during impact were represented by the modification of response frequency spectrum. Discussions were made from energy point of view. We defined “attribute energy” in the form of frequency character to indicate surface status.