This paper aims at contribution to the selection of a suitable material for rocket nozzle throat by means of evaluation of the thermal shock resistance and the thermal shock fracture toughness of several varieties of graphite. The thermal shocks are given by an arc discharge heating at the central area of disk specimen simulating the thermal stress conditions of rocket nozzle throat. In these tests, determining the critical threshold values of electric power to initiate and/or propagate cracks in the disks, the thermal shock resistance Δ(=σ
tk/E
α, σ
t, tensile strength; k, thermal conductivity; E, Young's modulus; α, thermal expansivity) and the thermal shock fracture toughness ∇(=K
ICk/Eα, KIC, fracture toughness of mode I) are evaluated en bloc quantitatively. The Δ's and ∇'s of carbon fiber chips reinforced graphites and two-and threedimensional carbon fiber reinforced carbon composites are also determined and discussed concerning the suitability for rocket nozzle materials.
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