Mechanical spectroscopy observation of LiAlH4 decomposition

  • I haven't seen this posted before. Unfortunately the article is not open access.


    Mechanical spectroscopy observation of LiAlH4 decomposition

    Enrico Gianfranco Campari, Ennio Bonetti, Angelo Casagrande, Loris Ferrari, Giuseppe Levi


    https://doi.org/10.1016/j.jallcom.2019.152242


    Abstract wrote:

    Dynamic elastic modulus and internal friction of cold consolidated mixtures of Al and LiAlH4 powders have been measured. All reactions and decompositions occurring in LiAlH4 during a thermal run have been detected as dynamic elastic modulus anomalies and internal friction peaks, proving the effectiveness of mechanical spectroscopy for the study of alanate. These informations are complementary to calorimetric and thermogravimetric data.


    Highlights wrote:
    • Dynamic elastic modulus and internal friction of cold consolidated mixtures of Al and LiAlH4 powders have been measured.
    • LiAlH4 decomposition detected by means of mechanical measurements.
    • Complementarity of calorimetry and mechanical spectroscopy for the study of alanate.
  • Alan Smith

    Thanks. I've read it earlier, but wasn't sure whether I could put it on the forum since it's paywalled.


    The authors consolidated (cold-pressed) at 1 Gpa pressure (which should be equivalent to about 10 tons/cm2) mixtures composed of 200–350 mg Al + 40–60 mg LiAlH4 material (Alfa Aesar, used as-received) into 1 mm-thick bars and ran in addition to the usual differential scanning calorimetry studies also mechanical measurements measuring their internal stress (as far as I understand) as they were heated. It turns out that changes on this regard are also related to the decomposition and transformations of the LiAlH4 into other phases, so they can be considered a novel way of studying the decomposition steps of LiAlH4 which could be used in addition to calorimetry.


    Of possibly more relevance to LENR, it appears that following decomposition at a heating rate of 3–5K/min, the so-formed bars after the first decomposition step of LiAlH4 become rich of pores and crack features. Furthermore these bars do not show the typical endothermic response just before such first decomposition step of LiAlH4. Heat treatment above 700K may remove such defect network, at least in the case of pure Al powders.


    I haven't read any direct suggestion of anomalous heating effects, which is a bit of a disappointment given the authors. If there is, it's obfuscated in the text or data. It could be that I need to read the paper more carefully.