Yoshinori Hattori

Cyclic Fatigue behavior of Ceramics

In recent years, ceramics have been investigated because of their application as structual components at high temperature. A great deal of this research has dealt with various mechanical properties. Although, considerable effort has been made in the study of fracture strength and creep properties, comparatively a little is known about the fatigue behavior under cyclic stress. Fatigue studies of alumina are reported by S. Pearson(1), F. Guiu (2), etc., and silicon nitride by R. Kossowsky(3), T.M. Yonushonis and K.E. Fofer(4), and life prediction of ceramics under cyclic heat stress is reported by N. Kamiya and O. Kamigaito(5).

Development of Gas Pressure Sintered Silicon Nitride and Its Automotive and industrial Application

The gas pressure sintering (GPS) process of silicon nitride is capable of producing sintered material of better quality than that obtained with the conventional normal sintering methods, and can be performed in a procedure simpler than the HIP method. These features of the GPS process have made it a promising manufacturing process for high quality silicon nitride ceramics. However, because sintering is performed in a high pressure atmosphere in this process, a 2-step sintering method had to be developed. This method and its development, are described in this paper.