Composite Insulators For 3000 Degree Celsius Environments

AN IMPORTANT COMPONENT OF ARCJET THRUSTERS IS THE INSULATOR HOLDING THE CATHODE BASE AND SEPARATING THE ELECTRODES. THE CURRENT BASELINE MATERIAL IS BORON NITRIDE (BN), WHICH IS WELL KNOWN FOR ITS HIGH ELECTRICAL RESISTIVITY AND HIGH THERMAL CONDUCTIVITY. HOWEVER, AT ARCJET OPERATING TEMPERATURE, BN HAS A DRAMATIC INCREASE IN ELECTRICAL CONDUCTIVITY AND A DECREASE IN THERMAL CONDUCTIVITY. ADDITIONALLY, THE VAPOR PRESSURE OF BN BECOMES APPRECIABLE ABOVE 2000 DEGREE C. A NEW COMPOSITE INSULATING MATERIAL WILL BE INVESTIGATED IN THE PROPOSED PROGRAM. THIS MATERIAL WILL HAVE A TAILORABLE THERMAL CONDUCTIVITY, LOW VAPOR PRESSURE AND HIGH ELECTRICAL RESISTIVITY WITH AN OPERATING RANGE UP TO 3100 DEGREE C.