# Research on Oxygen Components under a High-Pressure Oxygen Environment
## 2 Analysis
### Energy Spectrum Analysis  
In order to determine the location of the origin of the fire and thus verify factors inferring in the combustion analysis, microscopic observation and energy spectrum analysis of the oxygen valve were conducted using scanning electron microscopy and an energy-dispersive spectrometer.  
Scanning electron microscopy, abbreviated as SEM, is an observation method combining transmission electron microscopy and optical microscopy. SEM uses a narrowly focused high-energy electron beam to scan the sample, and extracts physical information through the interaction between the beam and the material. The information is collected, amplified, and reimaged to achieve the purpose of characterizing the microscopic morphology of the material.  
An energy-dispersive spectrometer, abbreviated as EDS, can be used to analyze the type and content of elements in micro-areas of materials, usually in conjunction with SEM. Each element has its own characteristic wavelength of X-rays. The magnitude of the characteristic wavelength depends on the characteristic energy \(\Delta E\) released during the energy level jump. EDS can be used to perform compositional analysis by using the characteristic energy of the different X-ray photons of different elements.  
The composition and ablation of the black adhesions were separately examined on each part of the oxygen nozzle. The locations for which the energy spectrum tests were carried out are shown in Figure 1. Location 1 is the distal end of the inlet. Location 2 is the proximal end of the inlet. Location 3 is the PA1010 oxygen valve. Location 4 is the middle area of the component. Location 5 is the gas cylinder end. Location 6 is the outlet end. These locations basically cover the inner cavity of the component. The observed images and energy spectrum are shown in Figure 2. A summary of the results of the energy spectrum analysis are shown in Table 1.  
Figure 1: The locations for which the energy spectrum analysis was carried out.  
Figure 2: \(Cont\).  
As can be seen from the results in Table 1, the Al content at location 3 was 36.01%, which is much higher than that found at the other locations. This indicates that the alloy coating at location 3 was the most severely damaged by the flames in the high-pressure  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Location**} & \multicolumn{8}{c}{**Content/\%**} \\ \cline{2-10}  & **O** & **Al** & **Mg** & **Cu** & **Zn** & **F** & **Ti** & **Fe** & **Cr** \\ \hline
1 & 45.10 & 25.35 & 0.52 & 1.93 & 0.63 & 1.19 & 0.50 & 0.35 & \\
2 & 36.62 & 22.68 & 0.49 & 4.75 & 1.60 & 2.38 & 0.97 & 0.65 & 0.19 \\
3 & 44.72 & 36.01 & 0.58 & 3.97 & 3.05 & & 1.17 & 0.90 & 0.19 \\
4 & 40.62 & 25.38 & 0.48 & 2.64 & 4.48 & & 1.01 & 0.87 & 0.23 \\
5 & 42.02 & 28.81 & 0.48 & 2.40 & 1.38 & 3.65 & 0.97 & 0.89 & 0.13 \\
6 & 38.73 & 24.34 & 0.49 & 1.97 & 0.84 & 1.23 & 1.05 & 0.68 & \\ \hline \hline \end{tabular}
\end{table}
Table 1: A summary of the results of the energy spectrum analysis.  
Figure 2: The observed images and energy spectrum. (**a**) Location 1. (**b**) Location 2. (**c**) Location 3. (**d**) Location 4. (**e**) Location 5. (**f**) Location 6.  
oxygen environment, indicating that location 3 is the area that experienced the most intense combustion in the entire inner cavity. Location 3 has a high probability of being the location of the origin of the fire. The Al contents at locations 1, 2, 4, 5, and 6 were similar and relatively low compared with location 3. The attached ablation products of these locations are similar.