Microstructure and Creep Behavior of Silicon Nitride and SiAlONs

Abstract

Microstructural evolution of silicon nitride (Si3N4) and SiAlON materials and its influence on creep resistance is reviewed. Grain size, grain morphology, and the ratio of α‐ to β‐phase grains play a part in resistance to creep. The glassy, intergranular phase typically has the strongest influence on creep. Creep data are usually obtained using uniaxial tensile or compressive tests, where creep in tension is controlled by cavitation and grain boundary sliding controls creep in compression. The impression creep methodology is also reviewed. An additional creep mechanism, dilation of the SiAlON grain structure, was found to be active in impression creep.

Incorporation of the transition metals (Cr and Fe) into β-SiAlON crystal structure

“…SiAlON ceramics have recently attracted increasing interest as promising engineering materials thanks to their outstanding mechanical properties, superior thermal stability, high creep resistance and good oxidation/corrosion performance [1,2]. It is well known that all these desired properties of SiAlONs are tailored by manipulating the microstructure, basically consisting of two distinct polymorphs (a-SiAlON and b-SiAlON) and secondary phases [1,2].…”

“…It is well known that all these desired properties of SiAlONs are tailored by manipulating the microstructure, basically consisting of two distinct polymorphs (a-SiAlON and b-SiAlON) and secondary phases [1,2]. Despite the fact that many of the alkali, alkaline earth and rare earth elements are commonly found to be incorporated into the a-SiAlON [3,4], none of these elements exist in b-SiAlON [1,5]. On the contrary, this view has been changing with recent studies revealing that some of the rare earth elements such as Eu 2+ and Ce 3+ can be accommodated into the b-SiAlON [6][7][8].…”

SiAlON Ceramics for the High Temperature Applications: High Temperature Creep Behavior

“…Meanwhile, the combination of SiAlON phases has a great influence on mechanical properties of SiAlON ceramics. Due to the different microstructure and composition, α and β-SiAlON have distinct contribution to creep resistance [10], [18].…”

“…The family of Si 3 N 4 solid solutions containing Al 2 O 3 along with other metal oxides is termed SiAlONs [10]. In this study creep behavior and high temperature mechanical properties of SiAlON ceramics were investigated at temperatures from 1100 ˚C to 1400 ˚C under stresses from 50 to 150 MPa in air by laboratory creep tests.…”

Solvent Based Slurry Functional Graded Thermal Barrier Coating for Application in Automotive Turbocharger Turbine Volute Casing

“…Advanced ceramics are the most thoroughly characterized materials and have become prime candidates for engineers and designers in a variety of wide range of applications which include heat exchangers, gas turbines, automotive engine components such as valves and tappets for cam followers, non-resonance knock sensors, spark plugs, turbocharger turbine rotors and housings as well as other wear resistance components subjected to elevated temperature conditions [9][10][11][12][13]. Their incorporation by Daimler-Benz as engine valves of some diesel engines and as high temperature components made by AlliedSignal for supplementary power unit of turbo engines and several turbine engine components [14] as well as the Rolls Royce Allison and Solar turbine programmes for the production of gas turbine components made from ceramics [15] are indications which demonstrated their practical capability, durability and reliability.…”