Modulus SiAlONs

With increasing zvalue the density of P-SiAlON decreases linearly, similarly lowering Young s modulus, strength, thermal conductivity, hardness and fracture toughness.30 On the other hand, for low zvalues (z< 1) the hardness and fracture toughness increase and when z > 1 they decrease. It has been also depicted that glass-free microstructures could be obtained in P-SiAlON polycrystals with substitutional level z> 2.31... 

As with other ceramic composites, the combination of a- and/or P-sialon with reinforcement agents results in sialon composites. This simple and obvious statement encompasses many factors which must be taken into account for successfully fabricating composites with a designed microstructure and improved properties (Prewo, 1989). For sialon matrix composites, the most important factors are physical compatibility including Young s modulus, elastic strain (Kerans and Parthasarathy, 1991) and thermal expansion coefficient (Sambell etal., 1972a, b), and chemical compatibility between sialon matrix... 

Figure 6. Modulus and microhardness of Sialon or oxynitride fibers versus nitrogen content. Redrawn from J. Kobayashi, M. Oota, K. Kada and H. Minakuchi, Oxynitride Glass and the Fiber Thereof, US Patent 4,957,883, September 18,1990.

Yield and absolute hardness, 72 Y-sialon glass density, 229 Knoop hardness, 229 Modulus, 229 Young s modulus of AljOj, 241, 259-261 anisotropy in /3-AI2O3, 281 of B4C, 228, 241 and bond type, 172 and crack depth, 155 and cracking, 147 of CrjCj, 302 of germanium, 252 of glass, 238 and hardness, 72 hardness ratio, 179 from Knoop indents, 180 mismatch stress, 273 of MgO, 241, 269 and penetration depth, 47, 240 and plasticity parameter, 241 and residual impression parameter, 240... 

---