钢中氢分布检测技术进展

主要介绍了几种目前应用比较广泛的氢分布检测技术的原理及其在氢渗透和氢脆研究中的应用,包括三维原子探针(Atom Probe Tomography,APT)、扫描开尔文探针力显微镜(Scanning Kelvin Probe Force Microscopy,SKPFM)、二次离子质谱法(Secondary Ion Mass Spectroscopy,SIMS)和氢微印技术(Hydrogen microprinting technique,HMT),以及可用来检测氢浓度的热脱附质谱技术(Thermal desorption spectrometry,TDS)等。总结了几种检测技术的原理和特点,并简要介绍了它们在与H有关领域里的典型应用。其中,APT和SIMS是利用质谱法直接检测H,以获得H在材料中的分布;SKPFM是通过H引起的电位变化,来获得H的分布;HMT是通过置换反应,即H原子将Ag+置换为Ag原子,Ag原子沉积在试样表面的分布来表征H的分布;热脱附法则是通过恒定的升温速率下H脱附速率对不同陷阱的敏感性差异,来获得不同陷阱中的H浓度以及H与陷阱的相互作用。这几种检测技术的空间分辨率可达亚纳米、纳米、微米至数微米直至毫米级。另外,SKPFM还具有时间分辨的功能。这些技术在H检测方面的应用,使得研究者对H在材料中的微观分布与聚集状态有了直观地认识,进而对由氢引起的失效破坏(即氢致延迟断裂的微观机理)有了更深刻的理解。最后还介绍了目前比较常用的检测H浓度的方法。

Progress of Detection Techniques for Hydrogen Mapping in Steel

The principles of several detection techniques for hydrogen mapping widely used at present and it’s applications in the study of hydrogen permeation and hydrogen embrittlement were introduced,including atom probe tomography(APT),scanning Kelvin probe force microscopy(SKPFM),secondary ion mass spectroscopy(SIMS)and hydrogen microprinting technique(HMT),as well as thermal desorption mass spectrometry(TDS)technique used for the detection of hydrogen concentration.Then,the principles and characteristics of several detection techniques were summarized and their typical applications in the fields related to hydrogen were introduced briefly.APT and SIMS were used to obtain the hydrogen mapping in materials by directly detecting hydrogen with mass spectrometry.SKPFM got the hydrogen mapping by the surface potential changes induced by hydrogen.The principle of HMT was to characterize the hydrogen mapping through the distribution of Ag atoms on the specimen surface through a substitution reaction(H atom substituted Ag+with Ag atom).As for thermal desorption technique,the hydrogen concentration at various traps and the bond strength between hydrogen atoms and traps at different sites were characterized by the sensitivity of desorption rates at constant heating rate to various traps.The spatial resolution of these techniques was from sub-nanometer to nanometer,micrometer and several micrometers and even millimeters.In addition,SKPFM had time resolution function.The application of these hydrogen detection techniques gives researchers an intuitive understanding on the microscopic distribution and aggregation state of hydrogen atoms in the material,thus providing a deeper understanding of the microscopic mechanism of hydrogen-induced delayed fracture.Finally,several common methods of detecting H concentration are mentioned.