Silicon Nitride-Based Materials

Recently, extensive studies of oxynitride glasses were conducted by various groups [56-67], the aim being to achieve a better understanding of the composite behavior of liquid-phase sintered Si3N4. 

7 LU2O3-4I.2 MgO-36.6 Si02-8.4Si3N4 glass with 24equiv% N. 

Interestingly, the Lu203-Mg0-Si02-N2 glass with 24equiv% N had the highest 

The rare earth-doped oxynitride glasses demonstrated higher densities and thermal expansion coefficients, but a substantially lower hardness, compared to the a- and P-Si3N4 single crystals. 

---

Thompson, D.P. (1989), Preparation and Properties of Silicon Nitride Based Materials, ed. D.A. Bonnell and T.Y. Tien, Materials Science Forum, Vol. 47, Trans Tech Publications, Aedermannsdorf, Switzerland. 

Since their mechanical properties are maintained at high temperatures (up to 1700 K), silicon nitride-based materials are attractive for use in high-temperature structural applications in chemically aggressive environments. For example, several properties of a Si3N4-based ceramic (Si3N4-l-SiC+TiN), suitable for ceramic engines, are shown in Table Vm. 

Li, Y.Q. (2005) Structural and Imninescence properties of novel rare-earth doped silicon nitride based materials. Ph.D. Thesis, Technical University of Eindhoven. 

Preparation and Properties of Silicon Nitride Based Materials Bonnell,... 

Fig. 12. (a) A cross section of multiple coatings of TiN on TiC on a silicon nitride-based tool material (b) multicoatings on a SiAlON-based tool material. 

Herrmann M, Klemm H, Schubert C (2000) Silicon Nitride Based Hard Materials. In Riedel R (ed) Handbook of Ceramic Hard Materials. Wiley-VCH, Weinheim, p 747... 

Klemm H, Herrmann M, Schubert C (1998) High Temperature Oxidation of Silicon Nitride Based Ceramics Materials. In Niihara K, Hirano S, Kanzaki S, Komeya K, Morinaga K (eds) 6th Int Symp Ceramic Materials and Components for Engines. Jap Fine Ceramic Ass, Tokyo, p 576... 

Final Report 2004, EC/BBW Contract No. ICA-CT-2000-10020, FP5 INCO-Copemicus project LAMINATES (Silicon Nitride Based Laminar and Functionally Graded Ceramic Composites for Engineering Applications), project partners University of Warwick (UK), FCT Technologie (Germany), Institute for Problems of Materials Science (Ukraine), Materials Research Center Ltd (Ukraine), Institute for Problems of Strength (Ukraine), Institute of Chemical Physics (Armenia), Drexel University (USA), EMPA (Switzerland). 

In the following chapter fundamentals of the high-temperature behaviour of silicon nitrides and silicon nitride-based composites will be presented. Depending on the sintering additive used, silicon nitride materials with different high-temperature properties can be obtained. Some typical materials are chosen from the broad variety of Si3N4 ceramics that exist and summarized in Table 4. 

Silicon nitride-based ceramics are promising engineering materials for application under corrosive and wear conditions [135-142]. However, the use of silicon nitride materials in hot acids under hydrothermal conditions and in bases is often limited by degradation of the materials. This is the impetus for current efforts for better understanding of the influence of the microstructure on the corrosion behaviour of silicon nitride materials and to improve the materials behaviour on its basis. Up to now, only a small amount of data about the mechanisms of corrosion and pitting formation exists. 

---