A study of the microstructural change of surface of the intermetallic compound LaNi[sub 5] by hydrogen absorption

Journal Article · Sun Aug 15 04:00:00 EDT 1993 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(93)90152-I· OSTI ID:6137219

Kim, Guen Hong; Chun, Chang Hwan ^[1]; Lee, Soo Guen; Lee, Jai Young ^[2]

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1. Advanced Technology Research Center Agency for Defense Development, Taejon (Korea, Republic of)
2. Korea Advanced Inst. of Science and Tech., Taejon (Korea, Republic of)

It is well known that the surfaces of metals and intermetallics that form hydrides play a crucial role in hydrogen absorption and desorption processes. There has been considerable interest in the surface of LaNi[sub 5] due to its high reactivity with hydrogen. Schlapbach et al. used x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and magnetic properties measurement techniques to investigate the surface of LaNi[sub 5]. In their experiments, surface segregation and decomposition were found to occur after hydriding which they concluded was due to the small amount of oxygen present as an impurity. Stucki et al. reported that a surface decomposition layer of 10 nm in thickness formed after several hydrogen absorption-desorption cycles at room temperature with 99.999% H[sub 2]. It is very difficult to prepare the TEM specimen of LaNi[sub 5] because it is brittle and breaks down into powder of 4-20 [mu]m particle size on first hydriding. This is believed to be the major difficulty for TEM studies. The conventional crushing methods for TEM specimen preparation of a powder samples damages the surface of LaNi[sub 5] particles. In the present study, TEM specimens of LaNi[sub 5] powders are prepared by a ion beam thinning methods, and analytical electron microscopy (AEM) analysis on the surface of LaNi[sub 5] is carried out in order to understand better the surface decomposition phenomena.

• OSTI ID: 6137219
• Journal Information: Scripta Metallurgica et Materialia; (United States), Journal Name: Scripta Metallurgica et Materialia; (United States) Vol. 29:4; ISSN 0956-716X; ISSN SCRMEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
360104 -- Metals & Alloys-- Physical Properties
ABSORPTION
ALLOYS
DATA
ELECTRON MICROSCOPY
ELEMENTS
EXPERIMENTAL DATA
HYDRIDES
HYDROGEN
HYDROGEN COMPOUNDS
INFORMATION
INTERMETALLIC COMPOUNDS
LANTHANUM ALLOYS
MICROSCOPY
MICROSTRUCTURE
NICKEL ALLOYS
NONMETALS
NUMERICAL DATA
POWDERS
RARE EARTH ALLOYS
SAMPLE PREPARATION
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
SURFACES
TRANSMISSION ELECTRON MICROSCOPY