Abstract:
PROBLEM TO BE SOLVED: To provide a small, lightweight, easily-handleable, and high- performance fiber fracture detection type stress measurement sensor. SOLUTION: When continuous fibers of silicon carbide based fiber are subjected to oxidation treatment in the air, an oxide coating is formed on the surface. Heat difference treatment or chemical treatment is applied for regulating the strength distribution of a single filament. A continuous fiber bundle 2 obtained in this way is arranged in one direction, and the continuous fiber bundle is integrated/combined to be molded with a base material such as a fiber reinforcing composite material serving as an insulating material, resin, metal or ceramic. When electrodes are attached to the obtained one directional composite member, a stress measurement sensor 1 is formed. In the silicon carbide based fiber, electric resistance is increased even before its fracture according to an increase in the stress, and in a low stress area, a gentle increase of the electric resistance fluctuation ratio is observed. However, the electric resistance fluctuation ratio is increased greatly once the fracture is started in the fiber.
Abstract:
PROBLEM TO BE SOLVED: To provide a method of producing a ceramic-based composite material, by which the ceramic-based composite material having a smooth surface can be obtained and the high temperature strength, the heat resistance and the hermetic property of the ceramic-based composite material can be improved. SOLUTION: A precursor solution for a matrix is effectively impregnated into each fiber 3x, 3y, 3z constituting a fiber reinforced body M1 by impregnating the solution into the fiber reinforced body M1 under a reduced pressure or a high pressure so as to reduce the amount of a residual gas in the fibers when the precursor solution for the matrix is impregnated into the fiber reinforced body M1. The fiber reinforced body impregnated with the precursor solution is dried while preventing the leakage of the precursor solution from the matrix, caused by the evolution of the gas. Thereby, the surface is made smooth, the gas in the precursor solution for the matrix is removed and the survival of air bubbles at the time of sintering is inhibited. Thus, the formation of pores in the matrix caused by the presence of the air bubbles at the time of sintering can be suppressed, and the highly hermetic ceramic composite material can be obtained in a high yield.