## 3 Results  
### Characterization  
The FESEM characterization of the samples is shown in Figure 2a-f, highlighting the surface morphology of the developed samples. A high level of micropores and macropores can be observed on the surface of the samples when analyzed under a microscope. However, no other surface damage was observed at the macro level. Nonetheless, when the sample was dipped under the aloe vera, the surface texture was somehow changed compared to the initial conditions. The dried aloe vera particles were observed under the microscope as a thin crusty layer covering the entire surface of the sample. After the coating, the entire surface looks like a defect-free surface, enveloped under a PLA film. The EDS analysis in Figure 2g-i revealed the presence of Mg and components of HA in the sample; however, these peaks tended to diminish after the coating with a new peak of Cl due to the availability of a small amount of chloroform in the coating. Figure 2: FESEM micrograph images of (**a**,**d**) porous Mg composite sample, (**b**,**e**) aloe vera loaded sample, (**c**,**f**) PLA coated sample, and (**g**–i) EDS images of the respective samples. Figure 3a shows the XRD patterns of the porous samples along with the aloe vera incorporated and PLA-coated samples. Mg and CaCO\({}_{3}\) show prominent peaks in the analysis and are marked correspondingly. The Mg peaks were available at 32.1\({}^{\circ}\), 34.6\({}^{\circ}\), 37\({}^{\circ}\), and 64.2\({}^{\circ}\), whereas 44.2\({}^{\circ}\) and 57\({}^{\circ}\) were the peaks shown by CaCO\({}_{3}\). These peaks are in agreement with the data available in references [50; 51; 52] as well as with the JCPDS cards for Mg (035-0821) and CaCO\({}_{3}\) (47-1743). The absence of any other distinguishable peaks shows that during the sintering, no further interfacial reactions occurred between the molecules of the materials. Moreover, Mg being the highest quantity projected the maximum peak intensity followed by CaCO\({}_{3}\), which tended to reduce after aloe vera incorporation and PLA coating. Figure 3: (**a**) XRD image of the developed composite samples, (**b**) FESEM cross-sectional images showing different coating thicknesses achieved over the porous samples. In comparison to metals, polymers often have lower atomic masses. The polymer coating on the coated sample may be able to absorb X-rays more efficiently than the metal substrate underneath when they interact with it. The intensity of the metal-related XRD peaks decreased consequently. Another important factor is the polymer coating's thickness. Greater attenuation of the X-rays by thicker coatings could result in a more noticeable peak intensity reduction. Therefore, the intensity of the peaks was reduced after coating with PLA; nonetheless, their presence was still discernible due to the low thickness of the polymer film. This shows that the coating was highly effective without any defects as the electrons from the electron beam could not penetrate through it, which, if possible, could show some peaks of the base substrate. The observed behavior is suitable in the current scenario as the better the coating, the better the protection of the substrate material, leading to improved mechanical and corrosion properties. These properties are discussed briefly in the mechanical and corrosion properties section. Moreover, cross-sectional imaging revealed the coating thickness (Figure 3b). It can be seen that with 5% PLA, the coating thickness achieved was 39.28 \(\upmu\)m, whereas, with 10% PLA, the thickness achieved was 78.56 \(\upmu\)m.  
The porosity of the samples was also observed under FESEM microscopy, as shown in Figure 4a-f.