Effect of High Temperature Heat Treatment on Phase Composition and Microstructure of SiBCN/HfC Ceramic Composites

Yuquan WEI; Yong YANG; Meng LIU; Qile LI; Zhengren HUANG

doi:10.15541/jim20190595

Journals >Journal of Inorganic Materials >Volume 35 >Issue 8 >Page 931 > Article

Journal of Inorganic Materials
Vol. 35, Issue 8, 931 (2020)

Effect of High Temperature Heat Treatment on Phase Composition and Microstructure of SiBCN/HfC Ceramic Composites

Yuquan WEI^1、2、3, Yong YANG^1、2、*, Meng LIU^1、2, Qile LI^1、2, and Zhengren HUANG^1、2、*

Author Affiliations

¹State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China

²Structural Ceramics and Composites Engineering Research Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China

³University of Chinese Academy of Sciences, Beijing 100049, China

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DOI: 10.15541/jim20190595 Cite this Article

Yuquan WEI, Yong YANG, Meng LIU, Qile LI, Zhengren HUANG. Effect of High Temperature Heat Treatment on Phase Composition and Microstructure of SiBCN/HfC Ceramic Composites[J]. Journal of Inorganic Materials, 2020, 35(8): 931 Copy Citation Text

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1. XRD patterns of raw powders and milled powders

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2. Microstructure and EDS element mapping of the amorphous SiBCN powders

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3. XPS spectra of amorphous SiBCN powders

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4. EFTEM images (a) and EELS spectra (b) of the amorphous SiBCN powders

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5. XRD patterns of the SiBCN/HfC ceramic composites before and after heat-treatement for 1 h at different temperatures

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6. Microstructure (a) and EDS element overlap mapping (b) of the as-sintered SiBCN/HfC ceramic composites, and its corresponding element distribution displayed in lower two rows

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7. TEM images of the SiBCN/HfC ceramic composites (a) before and (b) after heat treatment at 1800 ℃with insets showing the corresponding SAED patterns of dark area in (a) and (b)

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8. Change of standard Gibbs free energies of reactions (1)-(9) as a function of temperature

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9. Surface morphologies and corresponding EDS results of the SiBCN/HfC ceramic composites before and after heat treatment at different temperatures

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Reaction	ΔG_{1300 ℃}/(kJ·mol^-1)	ΔG_{1400 ℃}/(kJ·mol^-1)	ΔG_{1500 ℃}/(kJ·mol^-1)	ΔG_{1600 ℃}/(kJ·mol^-1)	ΔG_{1650 ℃}/(kJ·mol^-1)	ΔG_{1800 ℃}/(kJ·mol^-1)
HfO₂ + B₂O₃ + 5C = HfB₂ + 5CO(g)	169.8	91.0	12.6	-65.3	-104.1	-210.0
HfO₂ + 2BN + 2C = HfB₂ + 2CO(g) + N₂(g)	246.5	196.6	146.9	97.4	72.8	-0.7
HfO₂ + 3C = HfC + 2CO(g)	115.6	82.1	48.8	15.7	-0.8	-50.1
HfC + 2C + B₂O₃ = HfB₂ + 3CO(g)	54.1	8.8	-36.2	-81.0	-103.3	-169.9

Table 1. Change of standard Gibbs free energies of reactions (6-9) at different heat treatment temperature

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