Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1635076 | Rare Metals | 2008 | 7 Pages |
Abstract
Thermal stability of nanostructured NiCrC coating prepared by high velocity air-fuel (HVAF) spraying of cryomilled feedstock powders was investigated. Transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) were utilized for characteristic analysis. Recrystallization and normal grain growth occur when isothermal treatment is performed at 923 K (0.55 TM) for up to 100 h, and the average grain size increases from initial 41 nm for as-deposited state to around 100 nm for nearly equilibrium state. Isochronal treatment at 823 K and 1023 K was also conducted for comparison. Accordingly, for 0.49 to 0.61 T/TM, the time exponent n deduced from D1/n - D01/n = kt increases from 0.15 to 0.30. The observed high thermal stability is attributed primarily to a Zener pinning mechanism arising from the fine Cr2O3 dispersions and the solute drag effect as well.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Hua CUI, Kai TAO, Xianglin ZHOU, Jishan ZHANG,