Thermal stability of nanostructured NiCrC coating prepared by HVAF spraying of cryomilled powders  

作　　者：CUI Hua TAO Kai ZHOU Xianglin ZHANG Jishan 

机构地区：[1]School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China [2]State Key laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China

出　　处：《Rare Metals》2008年第4期418-424,共7页稀有金属（英文版）

基　　金：the National High Technology Research and Development Program of China (No.2002AA331080)

摘　　要：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 D^1/n - D0^1/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.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 D^1/n - D0^1/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.

关 键 词：nanostructure coatings grain growth heat treatment high velocity air fuel （HVAF） CRYOMILLING 

分 类 号：O78[理学—晶体学]