Primary Study On Preparation Of Al₂O₃/Cu Composites By Pressureless Infiltration

Al₂O₃/Cu composites have the potential use in wide field. High volume percentage Al₂O₃/Cu composites possess stronger intensity,higher wear resistance and better erosion resistance. Pressureless infiltration, which is fit to fabricate high volume percentage Al₂O₃/Cu composites, needs good wet ability between copper melt and alumina. The intrinsic wet ability is bad, which means it can't satisfy the requirement of pressureless infiltration. According to reported results, the Cu-Ti-O coating in the alumina can improve the wetting between copper melt and alumina ceramic.Fabricating Cu-Ti-O film by Sol-Gel process is mainly studied in the article. The sol solution for forming film is consisted of TiCl₄, CuCl2 and so on. After heat-treating, Cu-Ti-O coating is gotten on the matrix. The detailed experiment includes two steps, fabrication of TiO₂ coating and forming Cu-Ti-O film by appending Cu element. The first step is aim to find the basic principle of forming film through Sol-Gel and get basic theory for analyzing reaction of solution in the next step. TiO₂ coating is plated on the surface of slice and alumina using sol solution which is consisted of TiCl₄,C2H5-OH and H2O. Reaction principle in the solution is analyzed and the affection of titanium atomic concentration for TiO₂ film weight is sawn about. Phase composition is found by X-ray diffraction and the film is observed with scanning electric microscope. The results indicate that after heat-treating under 550℃, the coating is composed of anatase-TiO₂ particles. At the second step, Cu-Ti-O film is fabricated on the substrates of slice and alumina by the use of sol solution confected by putting CuCl2 in the solution for fabricating TiO₂ coating. The reaction principle of solution and the process of producing Cu3Ti3O are analyzed. The phase composition is detected by XRD and the film is observed through SEM. The results show that Cu-Ti-O film with flaw due to shrinkage of gel is composed of particles. Cu-Ti-O coating heated under 550℃on the slice is composed of anatase-TiO₂,CuO and Cu3Ti3O.The solution buildup greatly affects phase composition. When the atomic proportion of Cu versus Ti is up to one in the solution, the percentage of Cu3Ti3O accounts for more in the phase composition. The Cu-Ti-O coating heat-treated under 550℃on the ceramic substrate is consisted of anatase-TiO₂,CuO and Cu₂Ti₄O.With the increasing of the atomic proportion of Cu versus Ti, the percentage of CuO becomes bigger. When the proportion is up to five, CuO in sheets are clearly observed in the coating.