2.3.2 XRD test
The 2cm3 sample is hammered inside the specimen and
immersed in anhydrous ethanol for 7 days. Then, dry it in a drying oven
with the temperature of 50°C to a constant weight, and ground it into
powder. Further, it is sieved through a 200 mesh sieve to obtain the
powder.. Finally, the XRD test is conducted with an Empyrean polycrystal
X-ray diffraction analyzer whose the diffractometer scan range is 5 to
90°.