Si3N4 ceramics formed by HIP using different oxide additions — relation between microstructure and properties

摘要: Si3N4-based ceramic materials formed by glass encapsulation and hot isostatic pressing (HIP) using different additions of Al2O3, Y2O3 ZrO2 have been characterized analytical electron microscopy X-ray diffractometry. The microstructures related to formation process room temperature hardness fracture toughness the ceramics. A high volume fraction retained α-Si3N4 after processing at 1550 °C gave Si3N4 ceramics hardness. equi-axed grain morphology matrices in these materials, which contained only small amounts residual glass, resulted comparatively low values. Processing 1750 reduced amount substantially. When was added, microstructure a large present mainly as aspect ratio β-Si3N4 grains. This type an material with combined lower Additions and/or Al2O3 also extremely major part These exhibited medium values, however, larger appeared slightly increase toughness.