Two polymorphs, α' and β, are known to be major phases in pure distrontium silicate (Sr2SiO4) at atmospheric pressure. Fully dense pellets were fabricated by sintering chemically prepared powders in the temperature range of 900° to 1400°C for 1 to 5 hours. Their phases and microstructures were studied by TEM. At lower sintering temperatures such as 900°C, the major phase was orthorhombic α' (space group, Pmnb). The euhedral α' grains had a size of about 1 μm diameter (Fig. la). As the sintering temperature increased, the amount of monoclinic β phase (space group, P21/n) tended to increase. These β grains were usually irregular and twinned on {100}β or {001}β planes. Concentration of the electron beam on the grains gave rise to a disappearance of twins (Fig. lb).
Experimental characterization of the transverse phase space of a 60-mev electron beam through a compressor chicane