Abstract: A complex-shaped bonded body of silicon nitride having a high bonding strength of more than 30 kg/mm.sup.2 as flexural strength and continuously homogenous microstructure through the bonded portion can be obtained by the method comprising the following five steps:(a) molding a body from a mixture of silicon powder having a diameter of less than 44 .mu.m and non-oxide ceramics powder having a diameter of less than 44 .mu.m,(b) heating a molded body obtained by step (a) at a temperature of 600 to 1500.degree. C. in a non-oxide atmosphere such as nitrogen or argon gas to sinter said silicon powder and partially convert to silicon nitride retaining 60 to 100 wt. % unreacted silicon powder therein,(c) grinding a surface to be bonded together with other bodies of said presintered body obtained by step (b) to dispose of unreacted silicon thereon,(d) placing a bonding agent containing silicon powder having a diameter of less than 44 .mu.

Abstract: A shaped body of silicon nitride enjoying high density, ample shrinkage, and outstanding mechanical strength is produced in a desired pattern by a method of preparing a shaped body comprising Si particles and a compound capable of remaining as SiC or C in the form of film on the surface of the Si particles in a non-oxidative atmosphere at a temperature in the range of 900.degree. to 1,400.degree. C., subjecting the shaped body to sintering and shrinkage of not less than 1% in an atmosphere of inert gas at a temperature exceeding 900.degree. C., and not exceeding the softening point of Si, and subsequently subjecting the resultant sintered shaped body to nitriding in a nitriding atmosphere at a pressure exceeding atmospheric pressure and at a temperature in the range of 1,200.degree. to 1,500.degree. C.

Abstract: Flaky .beta.-SiC mainly composed of .beta.-SiC which is obtained from an organic silicon polymer containing the carbon and silicon atoms as the major skeletal component and the method for producing such flaky .beta.-SiC are disclosed. Such .beta.-SiC is especially utilized as the starting material for ceramics having a laminar structure as well as for the refractories. The ceramics and refractories provided with such .beta.-SiC have excellent resistance to thermal shock, to thermal fatigue as well as to oxidation.

Abstract: Flaky .beta.-SiC mainly composed of .beta.-SiC which is obtained from an organic silicon polymer containing the carbon and silicon atoms as the major skeletal component and the method for producing such flaky .beta.-SiC are disclosed. Such .beta.-SiC is especially utilized as the starting material for ceramics having a laminar structure as well as for the refractories. The ceramics and refractories provided with such .beta.-SiC have excellent resistance to thermal shock, to thermal fatigue as well as to oxidation.

Abstract: Flaky .beta.-SiC mainly composed of .beta.-SiC which is obtained from an organic silicon polymer containing the carbon and silicon atoms as the major skeletal component and the method for producing such flaky .beta.-SiC are disclosed. Such .beta.-SiC is especially utilized as the starting material for ceramics having a laminar structure as well as for the refractories. The ceramics and refractories provided with such .beta.-SiC have excellent resistance to thermal shock, to thermal fatigue as well as to oxidation.