Machinability of High-Strength Porous Silicon Nitride Ceramics

Orthopedic applications of silicon nitride ceramics.

Silicon nitride (Si(3)N(4)) is a ceramic material developed for industrial applications that demand high strength and fracture resistance under extreme operating conditions. Recently, Si(3)N(4) has been used as an orthopedic biomaterial, to promote bone fusion in spinal surgery and to develop bearings that can improve the wear and longevity of prosthetic hip and knee joints. Si(3)N(4) has been ...

Synthesis, Microstructure and Properties of High-Strength Porous Ceramics

Microstructure of Spark Plasma-Sintered Silicon Nitride Ceramics

The microstructure and phase composition of the high-content Al2O3-Y2O3-doped spark plasma-sintered silicon nitride were investigated. Fully dense silicon nitride ceramics with a typical α-Si3N4 equiaxed structure with average grain size from 200 to 530 nm, high elastic modulus of 288 GPa, and high hardness of 2038 HV were spark plasma sintered (SPSed) at 1550 °C. Silicon nitride with elongated...

Interface structure and atomic bonding characteristics in silicon nitride ceramics.

Direct atomic resolution images have been obtained that illustrate how a range of rare-earth atoms bond to the interface between the intergranular phase and the matrix grains in an advanced silicon nitride ceramic. It has been found that each rare-earth atom bonds to the interface at a different location, depending on atom size, electronic configuration, and the presence of oxygen at the interf...

Microstructure evolution accompanying high temperature; uniaxial tensile creep of self-reinforced silicon nitride ceramics

Extensive transmission electron microscopy (TEM) has been performed to study the microstructure evolution of a self-reinforced silicon nitride associated with high temperature creep. A large population of strain whorls is observed in samples crept at relatively high temperatures and the strain whorls are not necessarily asymmetrical with respect to the grain boundary normal. Large angle converg...