Thermal Conductivity Design and Evaluation of Zirconium Phosphate Bonded Silicon Nitride Porous Ceramics

Abstract

In this Paper, Five Fundamental Effective Thermal Conductivity Structural Models (Series, Parallel, Two Forms of Maxwell-Eucken and Effective Medium Theory) Were Used to Analyze and Design Silicon Nitride Porous Ceramics. Then α-Si 3 N 4 Matrix Porous Ceramics Were Prepared with ZrP 2 O 7 as a Binder and Thermal Conductivity of ZrP 2 O 7 Bonded Si 3 N 4 Porous Ceramic Was Evaluated. ZrP 2 O 7 Bonded Si 3 N 4 Porous Ceramic Had Open and Interconnected Pore Structure which is either in EMT or in Maxwell-Euken 2. The Thermal Conductivity of ZrP 2 O 7 Bonded Si 3 N 4 Porous Ceramics Changes from 2.0 to 0.5 W/m•K with Increasing the Porosity from 20% to 51%. The Obtained Results Showed that the External Porosity Material with Maxwell-Euken 2 Structure Had the Lowest Thermal Conductivity in All Porous Materials. The Open and Interconnected Pore Structure of ZrP 2 O 7 Bonded Si 3 N 4 Porous Ceramics Provided much Lower Thermal Conductivity.