Correlation of Intergranular Amorphous Structures on Multi-levelled Phase Relationship in Sialon Ceramics: Retrospect and Prospect

doi:10.15541/jim20170452

Abstract

Abstract:

Phase diagram in Sialon ceramics and intergranular amorphous films in Si₃N₄ ceramics, are two successful aspects for fundamental studies in ceramic as an independent discipline. Although differing only in secondary compositions, the small gap in stoichiometry between the two systems divides structure, scale and scope in ceramic research. Started from this century, a series of analytical TEM methodology to probe into local composition within individual grains and even inside grain-boundaries have been developed. This provides the possibility to unify the phase diagram and intergranular structure in Sialon ceramics, especially for them to connect and correlate into a multi-levelled structure framework, which can develop not only an alternative approach to study phase transformation, but also a hierarchical structure-property relationship that serves the full-life circle of ceramic materials.

Key words: Sialon ceramics, phase diagram, intergranular structures, analytical TEM, phase transformation, review

CLC Number:

TQ174

GU Hui. Correlation of Intergranular Amorphous Structures on Multi-levelled Phase Relationship in Sialon Ceramics: Retrospect and Prospect[J]. Journal of Inorganic Materials, 2018, 33(2): 147-152.

Figures/Tables 10

Fig. 1 Early study of RE solid-solution in α-Sialon[23]

Fig. 2 Comparison of solid-solution in different grains from 3 Nd-α-Sialon samples[21]

Fig. 3 Intergranular amorphous pockets in Nd-α-Sialon(TP~ 10 nm, QP~100 nm)[21]

Fig. 4 Compositions measured from amorphous QP regions in Nd-α-Sialon[21]

Fig. 5 Sialon-section in Ca-Al-Si-O-N phase prism[27]

Fig. 6 Solid-solutions measured from Ca-α-Sialon grains[22]

Table 1 Nominal (x) and measured values by EPMA and AEM in Ca-α-Sialon ceramics[22]

	x	EPMA	AEM	Extra phase
CA03	0.3	-	0.25 (6)	β
CA06	0.6	0.4	0.36 (6)	-
CA10	1.0	0.7	0.64 (7)	21R
CA14	1.4	0.9	0.48 (5)	21R

Fig. 7 Segregation detection at GB in Ca-α-Sialon[22]

Fig. 8 Solid-solutions measured from individual grains (solid lines) and designed (dotted lines) in Ca-α-Sialon ceramics[20]

Fig. 9 Gradient of dopant segregation to grain-boundary subject to neighboring inter-granular glassy pockets in Nd-α-Sialon ceramics[20]

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