Kinetics of Gas Carburizing of Zr-1%Nb Alloy

The kinetic characteristics of thin-sheet (approx. 1 mm) Zr-1%Nb alloy samples after treatment in a carbon-containing gas medium (PAr+C3H8\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${P}_{\mathrm{Ar}+{\mathrm{C}}_{3}{\mathrm{H}}_{8}}$$\end{document} = 0.106 Pa) in a wide temperature range of 650-850 degrees C and time 1; 5 and 10 h were investigated. The carburizing of the alloy at temperatures of 650 and 750 degrees C occurs according to a law close to linear (n approximate to 1), and at 850 degrees C according to a law close to parabolic (n approximate to 2). The activation energy of the alloy carburizing in the temperature range of 650-850 degrees C at the propane partial pressure pC3H8\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${p}_{{\mathrm{C}}_{3}{\mathrm{H}}_{8}}$$\end{document} = 0.018 Pa was 2.21 kJ/mol. The distribution of microhardness and structure of the near-surface layers of the alloy was shown. The microstructure of the near-surface layers of the alloy after carburizing was determined. The alpha-Zr and ZrC phase content on the alloy surface after treatment in a carbon-containing gas environment is presented.