## 3 Results and Discussion  
### Formation of Nano-Titanium Dioxide as a Precursor  
The formation of titanium nano-oxide powders as precursors of composite synthesis was carried out by electrochemical oxidation of pure titanium in a chloride-nitrate melt in an argon atmosphere [27]. The main function of the nitrate melt is corrosion protection against the aggressive environment due to the formation of dense protective oxide layers on metals. Chloride-nitrate melts allow synthesizing both dense protective coatings and nanocrystalline powders of metal oxides such as Al\({}_{2}\)O\({}_{3}\), TiO\({}_{2}\), ZrO\({}_{2}\), and PbO [33; 34] varying the nitrate concentration in the flux. Due to the alkali nitrates' thermal instability, the temperature range of their application is narrow, while amorphous oxides are usually  
Figure 1: Processing schematic of Al/Al\({}_{2}\)O\({}_{3}\) nanocomposite. formed at low temperatures. It is necessary to synthesize oxides using salt electrolytes with higher melting points to increase the temperature of the crystalline metal oxide synthesis. The metal oxidation in the chloride-nitrate salt melt bulk at the current densities ranging from 3 to 5 mA/cm\({}^{2}\) lead to the accumulation of significant amounts of oxide nanopowder in the bulk salt electrolyte. The chemical composition and modification of the formed oxides depended mainly on the oxidation temperature. Despite the nanometer size of titanium dioxide crystallites (Figure 2a), the X-ray diffraction pattern contained main rutile titanium dioxide lines of 20 angle at 27.5\({}^{\circ}\), 36.16\({}^{\circ}\), 39.26\({}^{\circ}\), 41. 32\({}^{\circ}\), 44.14\({}^{\circ}\), 54.42\({}^{\circ}\), 56.72\({}^{\circ}\), 63.44\({}^{\circ}\), and 69.11\({}^{\circ}\) with diffraction plans (110), (101), (200), (111), (210), (211), (220), (002), and (301), respectively (JCPDS no. #88-1175) [35] (Figure 2c). The broadening of lines or a halo was not observed, which may be explained by the fact that the formed oxide particles were well-faceted cubic crystals, and not spheroids, as is often the case, which happens in the synthesis of nano-oxides by the sol-gel method. Titanium dioxide nanopowders synthesized in a molten chloride-nitrate electrolyte at the current density of 3.5 mA/cm\({}^{2}\) were characterized by a high degree of crystallinity and took the form of titanium dioxide cubes with a size up to 30 nm (Figure 2a). According to the results of the Raman spectroscopy of the sample obtained at 700 \({}^{\circ}\)C, peaks characteristic for the modification of rutile TiO\({}_{2}\) were determined in the Raman bands: 144 cm\({}^{-1}\), 448 cm\({}^{-1}\), 612 cm\({}^{-1}\) (Figure 2b). Figure 2: SEM image (**a**), Raman spectrum (**c**), and XRD pattern (**b**) of TiO\({}_{2}\) nanopowder in rutile modification synthesized in NaCl-CsCl-5% NaNO\({}_{3}\) at 700 \({}^{\circ}\)C.  
Further, rutile titanium dioxide nanopowder formed under the above conditions was used as a precursor. Various industrially sol-gel methods for nano- and micro-powders production in the form of rutile and anatase were previously studied as precursors for the synthesis of the nanocomposite. However, all these nanopowders were sedimented to the bottom of the crucible and reaction (3) (Table 1) did not proceed. The titanium dioxide nanopowder in the rutile modification synthesized by the electrochemical oxidation of titanium in a chloride-nitrate melt was the only precursor with which the above reaction was successful. Interaction between Molten Aluminum and Titanium Nanoloxide under the Layer of Molten Halides and Analysis of Interaction Products  
The AMMC material dispersion reinforcement is typically achieved by casting or powder metallurgy, with the ceramic particles being introduced ex situ into a solid or liquid matrix. A new AMMC production method has been developed on the basis of the controlled \"in-situ\" chemical reactions; reinforcing fillers are formed during the chemical interaction between the matrix components and reactive additives [9; 12].