Abstract
Iron-10%lead. (0-5)%copper compacts having about 20% porosity were sintered at each temperature from 330°to 1150°C and various properties of their sintered compacts were measured.
The results obtained were as follows;
1) The sweating of lead from iron-lead-copper compacts appeared at the temperature just above the melting point of lead, and the vapouring of lead from the compacts was brisk at the temperature over about 900°C. However, these phenomena were able to be suppressed by the increase of copper powder contents.
2) At the temperature over about 700°C, all the compacts began to shrink by the sintering between iron powder particles. But at the temperature over about 800°C, only the compacts having comparatively high contents of copper powder exihibited a tendency to expand by the copper alloying into the iron skeleton through the liquid lead-copper.
3) Pore-structures of the compacts containing no copper powder hardly changed at the temperature below about 1000°C. However, those of the compacts containing a little of copper powder were developed by melt-off pores of lead powder which appeared at temperature about 700°C.
4) Increase of the strength of the compacts was obstructed by the contents of lead powder. But the copper alloying into the iron skeleton caused by the addition of copper powder to the compacts could improve the above negative effect.
From the aboves, it was concluded that the sintering temperature for producing the iron-lead-copper sintered alloys for porous bearings must be selected in the range from 800°C to 900°C.
