Abstract: A testing apparatus is described that enables both single and double-ended tubular members to be tested under pressure and at elevated temperatures. For double-ended tubular members, the apparatus comprises first and second pressure seals at either end of the tubular member under test, both seals including annular compliant members that bear upon the internal surface of the tubular member. A heater is positioned within the tubular member and one of the pressure seals has an orifice through which the heater is connected to a power source. Pressurization occurs through an orifice in the other pressure seal and cooling apparatus surrounds the first and second ends of the tubular member to cool the pressure seals, thereby enabling the annular compliant members to retain their compliancy when the tubular member is heated to test temperature. For single-ended tubular members, a single pressure seal is used having pathways for both electrical and pressurization connections to the interior of the tubular member.

Abstract: A tough, ablative-resistant, dielectric ceramic material is constructed using powder metallurgy techniques. The composite comprises a boron nitride particulate phase immersed in an Al.sub.2 O.sub.3 matrix. The boron nitride particles are preferably 3-5 microns in size, and create the capability of sustaining thermal strains without generating the thermal stresses that lead to material failure. The composite displays superior mechanical strength characteristics.