Search

The Cu-Al2O3 composite materials applying for electrode materials were successfully synthesized by internal oxidation process. The process included steps: producing solid solution α-Cu[Al] and oxidizing completely solid solution α-Cu[Al] as powders, then adding pure Cu powders and mixing in planetary ball milling, the mixtures were compressed into cylindrical samples, reduced at 750°C in 3h and sintered at 950°C in 2h in reduction atmosphere. The XRD patterns showed that total Al in Cu-matrix were completely oxidized in range of 20¸25h. After reducing and sintering process, the final products were Cu-Al2O3 composite materials. The results showed that micro-hardness, porosity and compress strength of Cu-Al2O3 materials increased with increasing of Al2O3 content, which was the result of dispersion of the fined Al2O3 grains in Cu-matrix. When Al2O3 content was unchanged, the porosity of received materials decreased with increasing of compress pressure. Whereas, the electrical conductivity of Cu-Al2O3 composite materials decreased comparing with pure Cu and it decreased with increasing of Al2O3 content.

Nano Al2O3 dispersion - strengthened Cu-matrix composite materials were fabricated by mechano-chemical method. The method carries out at room temperature by mechanical milling in the attritor in 16h hours using the mixtures of CuO, Al and Cu powder ingredients, and then the mixtures were cold pressed into cylindrical samples and sintered at various temperatures (from 700°C to 900°C) and time (from 1 to 3 hours) in argon atmosphere. The XRD pattern and EDS results revealed that Al2O3 phases were formed and dispersed into Cu-matrix during mechano-chemical process. The Al peak disapeared at the end of mechano-chemical process and the final obtained products were Cu-Al2O3 composite materials with Al2O3 content of 3-10% volume. The SEM and EDS results also showed that the particle sizes of Al2O3 were in about (50÷100)nm and uniformly dispersed within the C-matrix. The porosity of materials strongly depends on pressure compress, sintering time and temperature. It decreases with increasing of these parameters and reaches about 5%. The porosity and Al2O3 content affected on mechanical properties of materials, such as micro-hardness and compress strength, due to the dispersion of nano-Al2O3 into Cu-matrix. The conductivity of materials decreases with increasing porosity and Al2O3 content.