Young's modulus of silicon nitride hot pressed with ceria additions

Abstract

Possible relationships between Young's modulus at room temperature of (1–20) wt% CeO₂-fluxed HPSN and some microstructural features such as amount of the intergranular phase, porosity, α/β ratio and crystallographic β texture have been investigated. The dependence of Young's modulus on amount of integranular phase expressed in terms of the Cohen-Ishai model resulted in the relation: $\text{E}\text{= 98.0 [1 +}\text{V}{}_{\mathrm{N}}\text{(1.45 −}\text{V}{}_{\mathrm{N}}{}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}\text{)]}\text{GN/m}{}^2$. A quadratic relationship, E = 290.0 (1 — AP + BP²), proved the most adequate to account for the effect of porosity on Young's modulus over the 0–36% porosity range. $\text{α}\text{β}$ ratio and β texture did not seem to have an appreciable effect.