Abstract: Disclosed are water soluble core wherein a particulate refractory material is combined with a binding agent comprising Na.sub.2 CO.sub.3, Na.sub.2 O . NSiO.sub.2 where n is 0.5 to 4, and SiO.sub.2 as ingredients and a process for producing the water soluble core. The process comprises mixing the particulate refractory material with a water glass, casting the mixture of the particulate refractory material and the water glass, hardening the casting by CO.sub.2 gas, and calcining the casting at between 100.degree. C. and a temperature less than that of an endothermic peak of the water glass in differential thermal analysis. Also, a process for die casting a metal is disclosed using the water soluble core which process comprises pre-heating the water soluble core from a temperature of 300.degree. C. below a melting point of the metal to a temperature of the endothermic peak.

Abstract: A fiber-reinforced metal composite (aluminum-matrix composite) consisting essentially of reinforcing fibers and an aluminum alloy containing 6 to 11 wt. % of nickel of a metal matrix.

Abstract: A fiber-reinforced metal composite consisting essentially of continuous reinforcing fibers disposed in an aluminum alloy matrix containing about 0.005 wt % of cobalt.

Abstract: A hybrid fiber-reinforced plastic composite material comprising a matrix of a plastic and hybrid fibers consisting of inorganic fibers and at least one kind of fibers selected from the group consisting of carbon fibers, glass fibers, boron fibers, aramide fibers and silicon carbide fibers having a carbon core, wherein(a) the inorganic fibers are inorganic fibers containing silicon, either titanium or zirconium, carbon and oxygen and being composed of(i) an amorphous material consisting substantially of Si, M, C and O where M represents Ti or Zr, or(ii) an aggregate consisting substantially of ultrafine crystalline particles with a particle diameter of not more than 500 .ANG. of .beta.-SiC, MC, a solid solution of .beta.-SiC and MC and MC.sub.1-x, and amorphous SiO.sub.2 and MO.sub.2, where M is as defined and x is a number represented by 0<x<1, or(iii) a mixture of the amorphous material (i) and the aggregate (ii),(b) the composite material has an interlayer shear strength of at least about 9 kg/mm.sup.

Abstract: An inorganic fiber-reinforced metallic composite material comprising a matrix of a metal or its alloy and inorganic fibers as a reinforcing material, characterized in that(a) the inorganic fibers are inorganic fibers containing silicon, either titanium or zirconium, nitrogen and oxygen and being composed of(i) an amorphous material consisting substantially of Si, M, N and O, or(ii) an aggregate consisting substantially of ultrafine crystalline particles with a particle diameter of not more than 500 .ANG. of Si.sub.2 N.sub.2 O, MN, Si.sub.3 N.sub.4 and/or MN.sub.1-x, and amorphous SiO.sub.2 and MO.sub.2, provided that in the above formulae, M represents titanium or zirconium, and x is a number represented by 0<x<1, or(iii) a mixture of the amorphous material (i) and the aggregate (ii), and(b) said metal is selected from the group consisting of aluminum, magnesium, and titanium, or(c) said alloy is selected from the group consisting of aluminum alloys, magnesium alloys and titanium alloys.

Abstract: An inorganic fiber-reinforced ceramic composite material comprising a matrix of a ceramic and inorganic fibers as a reinforcing material, characterized in that(a) the inorganic fibers are specified inorganic fibers containing silicon, either titanium or zirconium, carbon and oxygen,(b) the ceramic is at least one material selected from the group consisting of carbides, nitrides, oxides, glass ceramics, graphite and specified inorganic materials containing silicon, either titanium or zirconium, carbon and oxygen,(c) the inorganic fibers have an initial reaction degradation speed of not more than 0.35 kg/mm.sup.2.sec.sup.

Abstract: An inorganic fiber-reinforced metallic composite material comprising a matrix of a metal or its alloy and inorganic fibers as a reinforcing material, characterized in that(a) the inorganic fibers are inorganic fibers containing silicon, either titanium or zirconium, carbon and oxygen and being composed of(i) an amorphous material consisting substantially of Si, M, C and O, or(ii) an aggregate consisting substantially of ultrafine crystalline particles with a particle diameter of not more than 500 .ANG. of .beta.-SiC, MC, a solid solution of .beta.-SiC and MC and MC.sub.1-x, and amorphous SiO.sub.2 and MO.sub.2, provided that in the above formulae, M represents titanium or zirconium, and x is a number represented by 0<x<1, or(iii) a mixture of the amorphous material (i) and the aggregate (ii),(b) the inorganic fibers have an initial degradation speed of not more than about 0.3 kg/mm.sup.2.sec.sup.

Abstract: An inorganic fiber-reinforced ceramic composite material comprising a matrix of a ceramic and inorganic fibers as a reinforcing material, characterized in that(a) the inorganic fibers are specified inorganic fibers containing silicon, either titanium or zirconium, nitrogen and oxygen, and(b) the ceramic is at least one material selected from the group consisting of carbides, nitrides, oxides, glass ceramics, graphite and specified inorganic materials containing silicon, either titanium or zirconium, nitrogen and oxygen.

Abstract: A method of preparing polycarbosilanes having high molecular weight and also having the major structural unit of silicon-carbon linkage. The method comprises heating a polysilane at 50.degree.-600.degree. C. in atmosphere of an inert gas and distilling out a low molecular weight polycarbosilane fraction having the number mean molecular weight of 300-600, followed by polymerizing the fraction by heating it at 250.degree.-500.degree. C. in atmosphere of an inert gas. The polycarbosilane obtained by the method of the present invention is useful for the precursor of preparing silicon carbide fibres and shaped articles.

Abstract: The carbonitrides of metals of Groups IV, V and VI of the Periodic Table are prepared by calcining a precursor obtained by (i) reacting the reaction product of ammonia and the halide of a metal selected from the group consisting of Groups IV, V and VI of the Periodic Table of Elements with polyphenol, or (ii) reacting the reaction product of polyphenol and the halide of a metal selected from the group consisting of Groups IV, V and VI of the Periodic Table of Elements with ammonia, the amount of the polyphenol being within the range defined by the following relationship: ##EQU1## wherein a is the number of hydroxyl groups contained in one molecule of the polyphenol, b is the number of moles of the polyphenol and c is the number of moles of the metallic halide. The desired metallic carbonitride in the form of finely divided powder having a uniform size and excellent sintering properties can be obtained at low energy consumption.

Abstract: The carbonitrides of metals such as those of Groups IV, V and VI of the Periodic Table are prepared by calcining a precursor obtained by (i) reacting the reaction product of ammonia and the halide of a metal with carbohydrate and/or polyvinyl alcohol, or (ii) reacting the reaction product of carbohydrate and/or polyvinyl alcohol and the halide of a metal with ammonia. The desired metallic carbonitride in the form of finely divided powder having a uniform size and excellent sintering properties can be obtained at low energy consumption.