**3.3 TEM result**

*Rare Earth Elements and Their Minerals*

calculated by the Scherer formula [7]

*<sup>D</sup>* = \_*<sup>k</sup>*

The XRD pattern of the Gd2O3 sample is shown in **Figure 3**. The diffraction patterns are well matched with standard JCPDS card no. 43-1015, indicating that the sample of Gd2O3 phosphor is in the pure monoclinic phase. The particle size was

where *D* is the volume weighted crystallite size, *k* is the shape factor (0.9), *λ* is the wavelength of Cu Kα1 radiation, *β*hkl is the instrumental corrected integral breadth of the reflection (in radians) located at 2*θ*, and *θ* is the angle of reflection (in degrees) utilized to relate the crystallite size to the line broadening. The average crystallite size of Gd2O3 nanoparticles was found to be in the range of 8–10 nm for both the fuels. No impurity peaks or other possible phases of Gd2O3 were observed. Further, the strong and sharp diffraction peaks confirm the high crystallinity of the

The scanning electron microscopy (SEM) was utilized as a focused ray of high energy electrons to produce an assortment of signs at the crystalline surface.

*<sup>β</sup>Cos<sup>θ</sup>* (1)

**3. Result and discussion**

**3.1 XRD result**

products.

**3.2 Surface morphology**

**80**

**Figure 3.**

*XRD patterns of Gd2O3: (A) glycerin fuel and (B) urea fuel.*

Transmission electron microscopy (TEM) is an imaging system whereby a light emission is engaged onto an example making a broadened form show up on a fluorescent screen or layer of photographic film or to be distinguished by a CCD camera. The main commonsense transmission electron magnifying instrument was built by Albert Prebus and Lames Hillier at the college of Toronto in 1938 utilizing ideas grew before by Max Knoll and Ernst Ruska. The particle size of the system was determined by high resolution transmission electron microscopy (HRTEM). It is a phase differentiated imaging process because the image formed is due to the scattering of electron waves through a thin surface. In **Figure 5**, HRTEM micrograph demonstrates a Gd2O3 nanocrystal with a width of 8–10 nm seen all through the particle for both fuels [1, 2, 7].
