The Densifining and the Strengthening of Sintered Cu Compacts Through the Addition of ZrO₂ Fine Powder

Abstract

It has been known that the Cu powder compacts often swell when sintered in H₂ gas, therefore the densification and the strength of the sintered compacts are limited to low levels. In this study 0.1-1.5 mass% ZrO₂ fine powder was mixed with Cu powder in order to prevent the swelling during sintering. These mixed powders were sintered in both H₂ and vacuum atmospheres at 850°C-1050°C.
It was shown that the addition of ZrO₂ fine powder was extremely effective on the prevention of the swelling of the Cu compacts during sintering, and the high densification was obtained. The reason why ZrO₂ fine powder prevent the swelling durring sintering could be explaned as follows: it may delay the formation of isolated pores by slowing down the sintering of Cu powder particles and simultaneously make the deffusion pathes for reaction gaseous. It was also shown that the most effective amounts of ZrO₂ fine powder on the densification of Cu powder increased with increasing sintering temperatures. The addition of ZrO₂ fine powder improved the tensile strengths of sintered Cu compacts because of its function to make the grains fine.