Tailoring of Mechanical Properties of Si3N4 Ceramics

Significant progress has been made in recent years in developing silicon nitride ceramics. The advances that have been achieved are mainly based on an increasing understanding of processing and microstructure-properties relationships. New analytical methods and high resolution transmission electron microscopy (HRTEM) coupled with extensive phase equilibria studies have provided new insights into the grain boundary region and offer the possibility to tailor the microstructure for specific applications. Because of the anticipated break-through in industrial applications there are still considerablt; research activities at industrial laboratories as well as other research centres. This volume presents the contributions to the international workshop "Tailoring ofHigh Temperature Properties of Si3N4-Ceramics" with 60 participants from 12 countries held on 6th - 9th October 1993 at SchloB Ringberg in Germany, the conference site of the Max Planck-Society. Additionally, it contains all invited papers of the International Conference "Silicon Nitride 93" held before the workshop on 4th - 6th October 1993 in Stuttgart/Germany. The book covers all recent research activities on silicon nitride ceramics and gives an overview with respect to recent developments.

Inhalt
I. Processing and Densification.- Colloidal Processing of Structurally Reliable Si3N4.- Silicon Nitride Materials for Engine Applications.- High Temperature Resistant Silicon-Nitride Ceramics by Optimized Two-Step Gas Pressure Sintering.- II. Microstructure Development, Characterization and Influence on Mechanical Properties.- Analysis of Microstructural Development and Mechanical Properties of Si3N4 Ceramics.- 3D Characterization of Sintered Microstructures with Prismatic Grains A Precondition for Microstructural Modelling of Si3N4 Ceramics.- Microstructural Contributions to the Fracture Resistance of Silicon Nitride Ceramics.- Improvement of Strength and Toughness of Silicon Nitride Ceramics.- III. Phase Diagrams and SiAlON Composites.- Calculation of Phase Diagrams of Multicomponent Systems.- ??? SiAlON Transformation.- High Performance Silicon Nitride Composite Ceramics Through Grain Boundary and Microstructural Tailoring.- SiAlON Composite Ceramics.- IV. Grain Boundary Phases: IV. 1. Properties of Oynitride Glasses.- Structure, Formation, and Stability of Oxynitride Glasses.- Rheological Behavior of YSiAlON Glasses Its Incidence on the High-Temperature Deformation of Si3N4 Ceramics Sintered with Al2O3 and Y2O3 Additives.- Devitrification Behavior of Oxynitride Glasses.- IV. Grain Boundary Phases: IV.2. Devitrification in Silicon Nitride Ceramics.- Crystallization of the Nanophase in Silicon Nitrides.- Crystallization of Grain Boundary Phases in Silicon Nitride and SiAlON Ceramics.- High Temperature Properties of Yb Containing Si3N4.- Processing, Phase Formation and Creep Behavior of Si3N4 with Y2O3 and Al2O3.- IV. Grain Boundary Phases: IV.3. Analysis and Characterization of Intergranular Grain Boundary Films.- High Resolution ElectronMicroscopy Studies on Silicon Nitride Ceramics.- Compositions and Thicknesses of Grain Boundary Films in Ca-Doped Silicon Nitride Ceramics.- The Intergranular Film in Silicon Nitride Ceramics: A Diffuse Interface Approach.- V. High Temperature Properties.- Creep Damage Mechanisms in Si3N4.- Creep Mechanisms in Silicon Nitride Ceramics.- Tensile Creep Rupture and Subcritical Crack Growth of Silicon Nitride.- Internal Stresses in Silicon Nitride and Their Influence on Mechanical Behavior.- Cyclic Fatigue Crack Growth in Si3N4-Ceramics.- Subcritical Crack Growth of Si3N4 under Thermal Loading by Light Irradiation.- Subcritical Crack Growth Resistance in Silicon Nitride Ceramics.- VI. Mechanical Performance and Applications.- Fracture Behavior of Silicon Nitride at Elevated Temperatures.- Mechanical Performance of a Commercial Silicon Nitride Pre-Exposed to a Sulphidizing Atmosphere at High Temperature.- Ceramics for Engines.- Fabrication and High Temperature Properties of Silicon Nitride Ceramics with Transition Metal Suicides Dispersion.- Author Index.