Abstract <p>The kinetic dependences of hafnium nitridization at temperatures of 1900, 2200, and 2500°C are established. The choice of temperature is based on the nitridization conditions of the Hf–Ti, Hf–Zr, and Hf–Nb metal pairs. By nitridization of Hf–Ti, Hf–Zr, and Hf–Nb pairs while maintaining the shape of the initial metal billets, binary compact nitrides are synthesized, and the features of the hafnium nitridization process in these bimetallic systems are determined. The sequence of phase and structural transformations proceeding in individual hafnium as part of each pair being nitridizated is established. The formation of hafnium nitride ceramics occurs through the formation of three- and two-layer gradient structures. Ceramics close to the stoichiometric composition of HfN is formed at temperatures of 2200°C and above. The value of the thermo-EMF of the Hf–Ti, Hf–Zr, and Hf–Nb systems is assessed, the character of the dependence of the Seebeck coefficient on the nitridization time is established, and its value is estimated.</p>

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Features of Hafnium Nitridization in Production of High-Temperature Thermoelectric Converters Based on Bimetallic Pairs Hf–Ti, Hf–Zr, Hf–Nb

  • I. A. Kovalev,
  • G. P. Kochanov,
  • T. Yu. Kolomiets,
  • A. A. Ashmarin,
  • S. V. Shevtsov,
  • A. V. Shokodko,
  • A. I. Ogarkov,
  • N. A. Ovsyannikov,
  • A. S. Chernyavsky,
  • K. A. Solntsev

摘要

Abstract

The kinetic dependences of hafnium nitridization at temperatures of 1900, 2200, and 2500°C are established. The choice of temperature is based on the nitridization conditions of the Hf–Ti, Hf–Zr, and Hf–Nb metal pairs. By nitridization of Hf–Ti, Hf–Zr, and Hf–Nb pairs while maintaining the shape of the initial metal billets, binary compact nitrides are synthesized, and the features of the hafnium nitridization process in these bimetallic systems are determined. The sequence of phase and structural transformations proceeding in individual hafnium as part of each pair being nitridizated is established. The formation of hafnium nitride ceramics occurs through the formation of three- and two-layer gradient structures. Ceramics close to the stoichiometric composition of HfN is formed at temperatures of 2200°C and above. The value of the thermo-EMF of the Hf–Ti, Hf–Zr, and Hf–Nb systems is assessed, the character of the dependence of the Seebeck coefficient on the nitridization time is established, and its value is estimated.