Experiment on ablation characteristic of EPDM insulator under particles erosion condition

Ablation experiments of particle erosion for EPDM basic formulation, overload resistance formulation, no SiO₂ formulation and no fiber formulation were performed on ground simulation test motor with high overload. Based on the results of ablation rate and surface characteristic of carburization layer, the formation mechanism of compact structure in carburization layer with both basic formulation and overload resistance formulation was studied. Ablation modes for variety formulation materials were analyzed as well. The results show that: the ablation ratios of different formulation at the same particles impacting conditions rank as follows: overload resistance formulation < basic formulation < no SiO₂ formulation < no fiber formulation. It also shows that there are huge discrepancies in the surface and fracture surface profiles of insulation layer, erosion modes and destroy mechanisms of different formulations. Compact and loose structures were formed in carburization layer of both basic formulation and overload resistance formulation during erosion process. While no SiO₂ formulation and no fiber formulation materials are destroyed mainly by graininess and sheet shape remove. Finally it shows that the erosion resistance of ablatives is improved by the compact structures on the surface, which are close related to the content of the fiber, SiO₂ and the erosion environment.