Brief Report on Technical Development Abroad: Astroceram, a Refractory Binder

摘要

A high grade refractory binder called 'Astroceram' was recently developed abroad. The working temperature of this binder is 2450 to 2900C. The binder has an excellent thermoshock property, an expansion coefficient of approximately 4.1 x 16 to the minus 6th power, an effective neutron capture cross section of 20 to 30 bars, a thermal conductivity of about 0.5 kcal/m.hr.deg., a Mohs hardness of 8 to 9, a tensile strength of 700 to 1050 kg/sq cm, a compressive strength up to 5600-10,500 kg/sq cm, a bending strength of 1600 kg/sq cm, a porosity not exceeding 0.2%, a dielectric constant of 9 and 7 to 9 at 60 and 1,000,000 cycles per second, respectively, and a volume resistivity of 10 to the 13th to the 15th power ohm/cm. The binder does not dissolve in hydrochloric, nitric and phosphoric acids. Nor does it dissolve in sulfuric acid at room temperature. The binder is suitable for use in the high-temperature reaction piles, rocketry and other special applications. It can also be used in the construction of electric or other high-temperature furances. 'Astroceram' binder may be divided into two types, A and B. Type A dries in air hardens without sintering and can be used at temperatures below 2450C; type B requires sintering and can be used at temperatures below 2900C. (Report quoted in its entirety.)