## 3 Results and Discussions
### Effects of Electrodeposition Parameters on Morphology and Composition of the Ni/SiCw Composite
\begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{_(hkl)_} & \multicolumn{6}{c}{**TC\({}_{0 ukh}\)**} \\ \cline{2-7}  & **2 mA\(\cdot\)cm\({}^{-2}\)** & **6 mA\(\cdot\)cm\({}^{-2}\)** & **10 mA\(\cdot\)cm\({}^{-2}\)** & **18 mA\(\cdot\)cm\({}^{-2}\)** & **25 mA\(\cdot\)cm\({}^{-2}\)** & **40 mA\(\cdot\)cm\({}^{-2}\)** \\ \hline
111 & 0.91 & 0.62 & 0.25 & 0.13 & 0.08 & 0.05 \\
200 & 0.66 & 1.73 & 2.17 & 2.63 & 2.84 & 2.9 \\
220 & 1.43 & 1 & 0.58 & 0.23 & 0.1 & 0.18 \\ \hline \end{tabular}
\end{table} 
Table 3: Texture coefficients of various (_hkl_) for the composite coatings as deposited at different current density. Figure 7: (a) XRD patterns of composites fabricated at a different current density, (b) The crystallographic orientation indexes of (111), (200) and (220). the intensity of the (200) increases, while (111), (220) peaks increases. The calculated orientation index of (200) plan increases from 1.08 to 2.32, while the (111) and (220) orientation index decreases from 1.15 to 0.32 and 0.73 to 0.36 (Figure 8b and Table 4), respectively. These results indicate that relative high electrolyte temperature is benefit for the preferred orientation of (200) plan, which is in agreement with previous studies [32]. In the view of the observations made by [PERSON] et al. [28], the energy barrier of nucleation showed a positive linear dependence with 1/\(\eta\) and 1/\(\eta\)2 for the 2D and 3D model, respectively; the nucleation kinetics of nickel crystallites depends on the applied overpotential \(\eta\). At low overvoltage, the particles near the cathode suppress metal ion reduction; while at high overvoltage, the transmission of the metal ions to the cathode becomes an important factor, moreover, the incorporated of inert whiskers enhance this transmission [23]. Therefore, the grains size of composites at high temperature becomes larger than that at low temperature (Figure 2). \begin{table}
\begin{tabular}{c c c c c c} \hline \multirow{2}{*}{**(\(\hbar k\))**} & \multicolumn{5}{c}{**TC\({}_{(\hbar k\hbar)}\)**} \\ \cline{2-6}  & **20** \({}^{\circ}\)**C** & **30** \({}^{\circ}\)**C** & **40** \({}^{\circ}\)**C** & **50** \({}^{\circ}\)**C** & **60** \({}^{\circ}\)**C** \\ \hline
111 & 1.15 & 1.05 & 0.8 & 0.51 & 0.32 \\
200 & 1.08 & 1.21 & 1.53 & 2 & 2.32 \\
220 & 0.73 & 0.73 & 0.71 & 0.51 & 0.36 \\ \hline \end{tabular}
\end{table} 
Table 4: Texture coefficients of various (\(\hbar k\)) for the composite coatings as deposited at different temperature. Figure 8: (**a**) XRD patterns of composites fabricated at a different temperature, (**b**) The crystallographic orientation indexes of (111), (200) and (220). Figure 9 shows the XRD patterns and its crystallographic orientation indexes of the Ni/SiC_w_ composite coatings electroplated under different stirring conditions. The XRD patterns (Figure 9a) shows that, under static conditions, the intensity of (200) peak is slightly higher than that of (220) peak, and (111) peak possess the highest intensity. When given a certain stirring speed at 100 rpm, there is about the same intensity of (111) and (200) crystal planes, while the intensity of (220) peak is very weak and almost disappeared. With increasing stirring speed to 300 rpm, the intensity of (200) peaks gradually increase, along with a relative decrease in intensity of (111) and (220) peaks. Notably, at high stirring speed (500 rpm), the intensity of (200) peak presents a weakening trend. This is because the excessive stirring speed takes a large impact force for the cathode surface, it can, therefore, caused the whiskers transferred with the electrolyte at a high speed. Ultimately, the content of whiskers incorporated into the nickel matrix is reduced. The XRD patterns further analysis is shown in Figure 9b and Table 5. The preferred orientation of the composite coating at different stirring speeds is mainly related to the content of SiC_w_ in coatings, and thereby the embedded SiC whiskers into the nickel matrix change the microstructure of the composites.