In-situ oxidation of sub micron copper powders

Generally if copper is sintered, the process takes place under a reducing atmosphere in order to remove the residual oxides at the surface of the copper powder. This is also especially valied for the consolidation of Cu nanopowders. Wtihin previous research work at ARCS rapid sintering techniques such as Spark Plasma Sintering or inductive hot pressing were used to consolidate Cu nanopowders without a reducing atmosphere. The result was a in-situ prepared composite material consisting of a copper matrix with fine dispersed Cu2 O particles. For many application of copper this is an unwanted effect because generally copper is used as a good conductor of heat or current. Within this research project the goal is to study the effect of the in-situ formation of Cu2 O during rapid sintering. The reasons for this internal oxidation are not clear and the relationship between processing conditions on the formation of Cu2 O will be studied. The Cu2 O volume content in the copper matrix as well as the distribution and size of the particles is a function of different processing conditions. Among these conditions there are the heating rate, dwell time, atmospheric pressure as well as the size, morphology and the oxygen content of the used copper powder. The goal of this project is study these mechanisms and the effect of the in-situ reinforcement on material properties such as thermal conductivity, thermal expansion, electrical and mechanical properties. Especially the thermal properties of this composite are of interest since copper has a good thermal conductivity and Cu2 O has a lower coefficient of thermal expansion compared to pure copper. Therefore these composite materials are attractive for use as heat sink in electronic power modules. Beside a scientific research of the in-situ formation of Cu2 O the project will also give an answer the question of possible applications of the material.

Generally if copper is sintered, the process takes place under a reducing atmosphere in order to remove the residual oxides at the surface of the copper powder. This is also especially valied for the consolidation of Cu nanopowders. Wtihin previous research work at ARCS rapid sintering techniques such as Spark Plasma Sintering or inductive hot pressing were used to consolidate Cu nanopowders without a reducing atmosphere. The result was a in-situ prepared composite material consisting of a copper matrix with fine dispersed Cu2 O particles. For many application of copper this is an unwanted effect because generally copper is used as a good conductor of heat or current. Within this research project the goal is to study the effect of the in-situ formation of Cu2 O during rapid sintering. The reasons for this internal oxidation are not clear and the relationship between processing conditions on the formation of Cu2 O will be studied. The Cu2 O volume content in the copper matrix as well as the distribution and size of the particles is a function of different processing conditions. Among these conditions there are the heating rate, dwell time, atmospheric pressure as well as the size, morphology and the oxygen content of the used copper powder. The goal of this project is study these mechanisms and the effect of the in-situ reinforcement on material properties such as thermal conductivity, thermal expansion, electrical and mechanical properties. Especially the thermal properties of this composite are of interest since copper has a good thermal conductivity and Cu2 O has a lower coefficient of thermal expansion compared to pure copper. Therefore these composite materials are attractive for use as heat sink in electronic power modules. Beside a scientific research of the in-situ formation of Cu2 O the project will also give an answer the question of possible applications of the material.