Materials characterization on efforts for ablative materials

Experimental efforts to develop a new procedure to measure char depth in carbon phenolic nozzle material are described. Using a Shor Type D Durometer, hardness profiles were mapped across post fired sample blocks and specimens from a fired rocket nozzle. Linear regression was used to estimate the char depth. Results are compared to those obtained from computed tomography in a comparative experiment. There was no significant difference in the depth estimates obtained by the two methods.