Journal of Inorganic Materials, Volume. 36, Issue 4, 443(2021)
In this study, the synthesis is feasibility and formulation design of HfN composite lanthanum silicate ceramics were explored. The feasibility of HfN synthesis by ternary reaction of HfO2-Si3N4-La2O3 system was verified by experiments, and the relationship between reaction pathway of HfO2-Si3N4 binary system and Hf-Si-La-O-N was studied. Considering that the lanthanum silicate salt in the reaction of HfO2-SiO2-La2O3 ternary system was contained in the Si3N4-SiO2-La2O3 system, lanthanum silicate was extended to the HfO2-Si3N4-La2O3-SiO2-HfN (Hf-Si-La-O-N) system, which clarified the coexistence of HfN and the lanthanum salt phases in the system. Experimental phase diagrams of HfO2-SiO2-La2O3 ternary system and Hf-Si-La-O-N system at 1500 ℃ were proposed. The results show that intermediate product Hf7O8N4 formed in the synthesis of HfN at high temperature in HfO2-Si3N4 binary system. Introduction of La2O3 promoted the system to generate HfN which was beneficial to reduce the burning loss rate of ceramics. There existed HfN and La4.67Si3O13, La5Si3NO12, LaSiNO2, La4Si2N2O7, La2Hf2O7 five lanthanum salt phases in the Hf-Si-La-O-N system.
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Yang LIU, Youjun LU, Yanrui LI, Liqun LIN, Zhenxia YUAN, Zhenkun HUANG.
Category: RESEARCH PAPER
Received: Jul. 7, 2020
Accepted: --
Published Online: Nov. 24, 2021
The Author Email: LU Youjun (youjunlu518@hotmail.com)