## 2 Materials and Methods
### Methods  
A digital Type D Durometer (LXD-D Shore hardness tester, made in Wenzhou, China) was used to assess the shore D hardness (HD) of the samples, adhering to the GB/T 2411-2008 [21] \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Symbol** & **PEEK (wt\%)** & **PPTA (wt\%)** & **PTFE (wt\%)** \\ \hline PEEK & 100 & 0 & 0 \\ PP2 & 98 & 2 & 0 \\ PP4 & 96 & 4 & 0 \\ PP6 & 94 & 6 & 0 \\ PP8 & 92 & 8 & 0 \\ PP10 & 90 & 10 & 0 \\ PT5 & 95 & 0 & 5 \\ PT10 & 90 & 0 & 10 \\ PT15 & 85 & 0 & 15 \\ PT20 & 80 & 0 & 20 \\ PT25 & 75 & 0 & 25 \\ PT30 & 70 & 0 & 30 \\ PT25 PP6 & 69 & 6 & 25 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Composition of PEEK-based composites. Figure 1: Experimental schematic of the preparation of PEEK and PEEK composites. standards. This process includes placing the polished sample on the testing platform, gently positioning the pressure probe of the hardness tester about 9 mm from the edge of the specimen, and noting the hardness value after both surfaces have reached a stable state. The final hardness value is determined by averaging five measurements taken from various locations. The density testing method adheres to the GB/T 1033.1-2008 [22] guidelines, considering PEEK composites as impermeable solid plastics following fine grinding and polishing. The impregnation method is utilized to determine their density, with the density of PEEK composites being calculated utilizing the specified Equation (1):  
\[\rho_{S}=\frac{m_{1}\times\rho_{W}}{m_{1}-m_{2}} \tag{1}\]  
where \(\rho_{s}\) is density (kg/m\({}^{3}\)), \(m_{1}\) is the mass of the sample in air (kg), \(m_{2}\) is the mass of the sample in the impregnating solution (kg), and \(\rho_{w}\) is the density of distilled water at 25 \({}^{\circ}\)C.  
The test method of tribological properties adheres to the standards set forth in GB/T 3960-2016 [23]. This process involves the use of a self-made shaft-block tribological tester (Figure 2) to determine the most effective preparation conditions for PEEK. In this setup, the friction pair consists of PEEK and a 45-steel shaft, with the latter having an outer diameter of 70 mm. The experiment is conducted under a load of 450 N and a linear velocity of 0.4 m/s over a duration of 2 h. Both components in the friction pair have a surface roughness of 0.35 to 0.4 \(\upmu\)m, and the testing environment involves dry friction. The average wear rate is derived through the application of Equation (2). \[W=\frac{\Delta V}{FL_{s}}=\frac{m_{3}-m_{4}}{\rho FL_{s}} \tag{2}\]  
where \(W\) is the volume wear rate (mm\({}^{3}\)/(N\(\cdot\)m)), \(m_{3}\) is the mass before wear (g), \(m_{4}\) is the mass after wear (g), \(\rho\) is the sample density (g/mm\({}^{3}\)), \(F\) is the normal load (N), and \(L_{s}\) is the total sliding distance (m). Further study into PEEK composites, which include PTFE and PPTA, was carried out utilizing the MTF-5000 Multi-function tribometer (RTEC, San Jose, CA, USA) (Figure 3). The experimental setup involved a TIMKEN A4138 (Timken, Saint Louis, MO, USA) bearing as the test ring (Figure 4), which has an outer diameter of 35 mm. During this testing phase, the conditions entail applying a 150 N load, maintaining a linear velocity of 0.4 m/s, and conducting the test for a total duration of 2 h. The surface roughness of the friction pair was adjusted to 0.35 to 0.4 \(\upmu\)m through machining, with experiments conducted under both dry friction and oil lubrication conditions. The lubricant utilized in this context is SpectraSyn 4 [24]. Post-tribological testing, the depth of wear was quantified utilizing a white light interference microscope (WLI, MFT-5000 from RTEC, San Jose, CA, USA, Figure 5), and the  
Figure 2: The shaft-block tribometer. displaying a pattern of decline followed by a rise in both the average COF and wear rate of PEEK, determining that the most effective sintering temperature is 380 \({}^{\circ}\)C for reducing both COF and wear rate.