Synthesis of Ternary Nitrides from Intermetallic Precursors: Modes of Nitridation in Model Cr3Pt Alloys To Form Cr3PtN Antiperovskite and Application to Other Systems
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- 作者：Michael P. Brady ; Sarah K. Wrobel ; Tom A. Lograsso ; E. Andrew Payzant ; David T. Hoelzer ; Joseph A. Horton ; and Larry R. Walker
- 刊名：Chemistry of Materials
- 出版年：2004
- 出版时间：May 18, 2004
- 年：2004
- 卷：16
- 期：10
- 页码：1984 - 1990
- 全文大小：412K
- 年卷期：v.16,no.10(May 18, 2004)
- ISSN：1520-5002
文摘
The use of intermetallic alloy precursors is explored as a new means to synthesize complextransition and refractory metal nitrides, carbides, and related phases. The conditions underwhich model single-phase Cr3Pt and two-phase Cr3Pt-dispersed Cr alloys form Cr3PtNantiperovskite when thermally nitrided were studied. Phenomenological experiments suggestthat the key variable to achieving single-phase Cr3PtN surface layers is the Cr3Pt phasecomposition. In two-phase 
-Cr-Cr3Pt alloys, the formation of single-phase Cr3PtN at Cr3Pt precipitates by in-place internal nitridation was found to be a strong function of the sizeof the Cr3Pt dispersion in the microstructure. Nanoscale Cr3Pt dispersions were readilyconverted to near single-phase Cr3PtN, whereas nitridation of coarse Cr3Pt particles resultedin a cellular or discontinuous-type reaction to form a lath mixture of Cr3PtN and a moreCr-rich Cr3Pt or -Cr. The potential for using such external/internal oxidation phenomenaas a synthesis approach to layered or composite surfaces of ternary ceramic phases (nitrides,carbides, borides, etc.) of technological interest such as the Ti3AlC2 phase, bimetallic nitride,and carbide catalysts (Co3Mo3N and Co3Mo3C and related phases), and magnetic rare earthnitrides (Fe17Sm2Nx or Fe17Nd2Nx) is discussed.
-Cr-Cr3Pt alloys, the formation of single-phase Cr3PtN at Cr3Pt precipitates by in-place internal nitridation was found to be a strong function of the sizeof the Cr3Pt dispersion in the microstructure. Nanoscale Cr3Pt dispersions were readilyconverted to near single-phase Cr3PtN, whereas nitridation of coarse Cr3Pt particles resultedin a cellular or discontinuous-type reaction to form a lath mixture of Cr3PtN and a moreCr-rich Cr3Pt or -Cr. The potential for using such external/internal oxidation phenomenaas a synthesis approach to layered or composite surfaces of ternary ceramic phases (nitrides,carbides, borides, etc.) of technological interest such as the Ti3AlC2 phase, bimetallic nitride,and carbide catalysts (Co3Mo3N and Co3Mo3C and related phases), and magnetic rare earthnitrides (Fe17Sm2Nx or Fe17Nd2Nx) is discussed.