Sialon applications

Yu, Z.B. and Thompson, D.P., (1998), Preparation of carbon fibre reinforced Li-alpha-sialon composites , in Gibson, G., Consolidating New Applications, Seventh International Conference on Fibre Reinforced Composite, Cambridge, UK, Woodhead, 264-270. 

The practical utilization of silicon carbide and silicon nitride ceramics or of SiAlON in the above-mentioned application sectors has steadily increased in recent years. Ca. 400 t/a of SN-powder is currently consumed in the manufacture of SN-components. The main applications are for cutting tools, roller bearings, dosing and deliver pipes for aluminum processing, as well as a multiplicity of other components which enjoy the advantages of SN-ceramics. 

M. Mimoto, Y. Tajima, Sintering Properties and Applications of SiliconNnitride and SiAlON Ceramics, J. Ceram. Soc. Jap., 99, 1014-1025(1991). 

Silicon nitride exhibits high strength at elevated temperatures and excellent thermal shock, creep, and oxidation resistance in hostile environments, which makes it ideal for gas turbine and diesel engine applications. The SiAlONs are variations on this theme. For example, SiAlON is being combined with boron nitride (BN) to produce a composite material that is reported to have incomparable thermal shock resistance. 

Better understanding of the microstructural formation of the oc -SiAlON materials in the future will be necessary for the improvement of the mechanical properties, especially fracture toughness and strength, and the wider application of this group of materials, having higher hardnesses than the P-Si3N4 and P-SiAlON materials (see Fig. 16). 

Silicon nitride has two major polymorphs a and P for engineering application, in addition to the amorphous and the cubic polymorph first reported in 1999. Both silicon nitride (Si3N4) and its form in solid solution (SiAlON) have been reviewed in detail " ". 

In this chapter, pure and dense P-Sig Al20jN8 2S (z= 1-3) were synthesized by CS followed by SPS without any sintering additives. The Vickers hardness, thermal conductivity, and the corrosion resistance in different atmospheres were investigated for the application as high-temperature engineering materials. In summary, this study introduced an effective method to synthesize pure and dense P-SiAlON materials and showed many valuable property data, which could provide significant references for the application in fields as engineering materials. The content of this chapter is based on the author s doctoral thesis [28]. 

Sialons are nitride-oxide hybrid ceramics based on the system Si-Al-O-N. or- and 5-sialons, especially, are used for metal-cutting and engineering applications [1]. They can be formally... 

The mechanical properties of SLAION ceramics can be tailored for specific applications by changing the starting composition this will result in a different ratio of the a- and P-SiAlONs [96, 97]. Hardness will be increased markedly with an increasing a-SiAlON content, and the presence of an elongated P-SiAlON will result in a higher fracture toughness of the final composite. 

Sialons constitute an important family of materials with unique structural features and various crystal chemistries. Because of their excellent mechanical properties and high temperature stability, sialon ceramics have been developed for structural engineering applications. Since the pioneering work of Krevel et al. [18] and Xie et al. [19], the rare earth-doped sialon phosphors have received increasing attention. In particular, Ca-a-sialon Eu [50] and P-SiAlON [21] phosphors have been proved to be good downconversion phosphors for white LED combined with a blue InGaN LED chip. 

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