Sintering of sedimented nickel powder gradual porous structures

Spherical nickel powder of 2-90 mu m particle size range was used in order to study the sintering behaviour of the gradual porous structures. According to Stoke's law, the sedimentation of dispersed particles from suspension starts with the coarser particles and ends with the finest ones. The obtained structures present gradient of particle size, porosity and pores size. The sintering degree of the structures varies among others with the particles size. The studied sintering temperatures were 950 and 1000 degrees C for 10 and 20 min in vacuum (1.3 x 10(-3) Pa). The influence of the sintering time on the pores size and the thickness of the sintering necks were studied. The characterisation of the used powder and the obtained gradual structures was carried out by laser scattering particles size analysis, scanning electron microscopy, image analysis and permeability measurements.