| Popis: |
Silicon nitride-based monolithic and composite ceramics have been developed extensively since the 1980s, due to their inherent beneficial properties and behaviors, including good toughness, strength (to elevated temperatures), oxidation- and creep resistance, low thermal expansion coefficient, and others. Processing of these materials is always a challenge, if one is to retain the best of the properties and behaviors in actual useful components. Many processes have been utilized, including the typical slip casting and dry- or isopressing followed by sintering. Other forming processes such as gel casting, freeze casting, and injection molding have been developed and are described herein. Other densification processes are also described, including hot pressing and hot isostatic pressing. The effect of processing on the mechanical reliability of the resulting ceramic component is stressed, illustrated with examples of the many types of failure-inducing flaws. |
