a RINT2000 diffractometer
(RIGAKU). The X-ray source was CuKα with accelerating
voltage of 40 kV, and the tube current of 40 mA. The XRD
patterns are typically plotted as the intensity of the diffracted
X-rays against the angle 2θ. The peaks will appear in the diffraction
pattern at the 2θ values when Bragg’s Law is satisfied. According
to the XRD patterns, the crystals present only the CaB2O4 phase,
and their patterns matched with the joint committee on powder
diffraction standards (JCPDS) record no. 32−0155. From the
results, no impurity phase was detected for both