Abstract: The carbon fiber precursor fiber bundle of the present invention is an acrylonitrile-based fiber bundle wherein the ratio of the length and width of the fiber cross section of a monofilament (length/width) is 1.05 to 1.6, and the amount of Si measured by ICP (Inductively Coupled Plasma) atomic emission spectrometry is in the range of 500 to 4,000 ppm. This type of carbon fiber precursor fiber bundle has a high compactness, and the carbonizing processing ability is good. Furthermore, for the carbon fiber bundle which is to obtained hereafter, the resin impregnating ability and tow spreading ability are good, the strength increases, and it has bulkiness. Furthermore, the carbon fiber precursor fiber bundle of the present invention is an acrylonitrile-based fiber bundle wherein the liquid content ratio HW is 40 wt. % or more and less than 60 wt. %.

Abstract: The carbon fiber precursor fiber bundle of the present invention is an acrylonitrile-based fiber bundle wherein the ratio of the length and width of the fiber cross section of a monofilament (length/width) is 1.05 to 1.6, and the amount of Si measured by ICP (Inductively Coupled Plasma) atomic emission spectrometry is in the range of 500 to 4,000 ppm. This type of carbon fiber precursor fiber bundle has a high compactness, and the carbonizing processing ability is good. Furthermore, for the carbon fiber bundle which is to obtained hereafter, the resin impregnating ability and tow spreading ability are good, the strength increases, and it has bulkiness. Furthermore, the carbon fiber precursor fiber bundle of the present invention is an acrylonitrile-based fiber bundle wherein the liquid content ratio HW is 40 wt. % or more and less than 60 wt. %.

Abstract: The carbon fiber precursor fiber bundle of the present invention is an acrylonitrile-based fiber bundle wherein the ratio of the length and width of the fiber cross section of a monofilament (length/width) is 1.05 to 1.6, and the amount of Si measured by ICP (Inductively Coupled Plasma) atomic emission spectrometry is in the range of 500 to 4,000 ppm. This type of carbon fiber precursor fiber bundle has a high compactness, and the carbonizing processing ability is good. Furthermore, for the carbon fiber bundle which is to obtained hereafter, the resin impregnating ability and tow spreading ability are good, the strength increases, and it has bulkiness. Furthermore, the carbon fiber precursor fiber bundle of the present invention is an acrylonitrile-based fiber bundle wherein the liquid content ratio HW is 40 wt. % or more and less than 60 wt. %.

Abstract: The carbon fiber precursor fiber bundle of the present invention is an acrylonitrile-based fiber bundle wherein the ratio of the length and width of the fiber cross section of a monofilament (length/width) is 1.05 to 1.6, and the amount of Si measured by ICP (Inductively Coupled Plasma) atomic emission spectrometry is in the range of 500 to 4,000 ppm. This type of carbon fiber precursor fiber bundle has a high compactness, and the carbonizing processing ability is good. Furthermore, for the carbon fiber bundle which is to obtained hereafter, the resin impregnating ability and tow spreading ability are good, the strength increases, and it has bulkiness. Furthermore, the carbon fiber precursor fiber bundle of the present invention is an acrylonitrile-based fiber bundle wherein the liquid content ratio HW is 40 wt. % or more and less than 60 wt. %.

Abstract: The carbonaceous body of the invention is prepared by shaping and sintering uniform powdery mixture composed of a powder of a low-temperature coke, a powder of boron carbide and a powder of silicon carbide in such a proportion that the weight proportion of the boron carbide and the silicon carbide is in the range from 2:98 to 80:20 and the volume proportion of the coke powder and the combination of the boron carbide and silicon carbide is in the range from 50:50 to 95:5. The carbonaceous body thus obtained is highly resistant against air oxidation even at a temperature of 1400.degree. C. in addition to the outstandingly high mechanical strengths in comparison with conventional carbonaceous shaped materials such as artificial graphite.