Pressure-induced amorphization of SrB2O4

SiB2O4, SrB2O4:Eu2+ and SrB4O7 have been studied by X-ray diffraction, infr ared absorption and luminescence measurements on samples after being treate d at pressures up to 16 GPa and temperatures up to 1400 degrees C using an octahedral anvil press. Besides, in-situ X-ray diffraction study using a di amond-anvil cell has been carried out on Sr2O4 at 18.7 GPa and room tempera ture. Beyond 7 GPa at room temperature, the orthorhombic phase of SrB2O4 be came progressively amorphous, associated with cross linking of the infinite chains of BO2 triangles. A red shift was observed in the luminescence spec trum of amorphous Eu2+-doped SrB2O4. No amorphization occurred in SrB4O7 un der conditions up to 9 GPa and 1400 degrees C. (C) 1999 Elsevier Science Lt d. All rights reserved.