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TY - JOUR AU - Mishima, O. AU - Calvert, L. D. AU - Whalley, E. PY - 1984 DA - 1984/08/01 TI - ‘Melting ice’ I at 77 K and 10 kbar: a new method of making amorphous solids JO - Nature SP - 393 EP - 395 VL - 310 IS - 5976 AB - Amorphous solids are made mainly by cooling the liquid below the glass transition without crystallizing it, a method used since before recorded history1, and by depositing the vapour onto a cold plate2, as well as by several other methods3,4. We report here a new way—by ‘melting’ a solid by pressure below the glass transition of the liquid—and apply it to making a new kind of amorphous ice. Thus, ice I has been transformed to an amorphous phase, as determined by X-ray diffraction, by pressurizing it at 77 K to its extrapolated melting point of 10 kbar. At the melting point, the fluid is well below its glass transition. On heating at a rate of ∼2.6 K min−1 at zero pressure it transforms at ∼117 K to a second amorphous phase with a heat evolution of 42±∼8 J g−1 and at ∼152 K further transforms to ice I with a heat evolution of 92±∼15 J g−1. In one sample, ice Ic was formed and in another, existing crystals of ice Ih grew from the amorphous phase. Heating below the 117 K transition causes irreversible changes in the diffraction pattern, and a continuous range of amorphous phases can be made. Similar transformations will probably occur in all solids whose melting point decreases with increasing pressure if they can be cooled sufficiently for a transformation to a crystalline solid to be too slow. SN - 1476-4687 UR - https://doi.org/10.1038/310393a0 DO - 10.1038/310393a0 ID - Mishima1984 ER -