Thermo-Mechanical Analysis of Si3N4-Based Seal Coatings on Si3N4 Substrate

Shan Liu; Fei Chen; Ying Yang; Qiang Shen; Kai Peng Zhang

doi:10.4028/www.scientific.net/KEM.508.42

Paper Titles

Thermal Conductivity Design and Evaluation of Zirconium Phosphate Bonded Silicon Nitride Porous Ceramics
p.21

Preparation of Nano-Sized ZrO₂ Powders by Polyvinyl Alcohol-Gel Method
p.27

Effect of Heating Rate on the Synthesis and Sintering of Ternary Carbide Zr₂Al₃C₄ through Spark Plasma Sintering
p.32

Densification and Microstructure of Monolithic TiN and TiB₂ Fabricated by Spark Plasma Sintering
p.38

Thermo-Mechanical Analysis of Si₃N₄-Based Seal Coatings on Si₃N₄ Substrate
p.42

Interface Reaction Behavior between Mn and SiO₂ Formed by RF Sputter Deposition
p.48

Phase Transformation and Densification of hBN-TiN Composites Fabrication by Spark Plasma Sintering
p.52

Formation of Mo₂S₃ Layers on the Surface of Graphitic Platelets
p.56

Foaming of CNTs/PMMA Nanocomposite with Supercritical Carbon Dioxide
p.61

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Thermo-Mechanical Analysis of Si₃N₄-Based Seal Coatings on Si₃N₄ Substrate

Abstract:

In this Study, a Good Combination between Si₃N₄-Based Seal Coatings and Porous Si₃N₄ Substrate Was Achieved by Room Temperature Spraying and Pressureless Sintering. To Evaluate the Joint Quality, Residual Stress due to Thermal Expansion Mismatch between the Coatings and Porous Layers Were Characterized by Computational Studies Using the Finite Element ANSYS Code. It Was Found that Si₃N₄-Based Seal Coating Allows a Gradual Change in Thermal Expansion Mismatch, Minimizing the Thermal Stresses Arising from Cooling or Heating. Further Theoretical Analysis Indicates that the Thermal Expansion Mismatch between the Two Layers Produced a Large Strengthening Effect for the Fraction of the Porosity below a Critical Level and that Substrates with the High Fraction of Porosity Showed Complete Cracking, as the Cracks Initiating in Adjacent Coatings. And the Volume Fraction of Pores Required to Cause Crack Deflection, in the Porous Layer, Was Predicted. The Effects of Layer Thickness and Porosity Fraction on Residual Stress Were Studied, which Are Used as Predictions towards Better Design of Composite Materials.