Study On Fabrication And Mechanism Of Porous Materials By Pulse Current Heating

Pulse Current Heating (PCH) is a newly developed process which makes possible sintering and bonding at low temperature and short time by charging the intervals between powder particles with electrical energy and effectively applying a high temperature spark plasma generated momentarily. Therefore PCH is considered to be effective on the fabrication of porous materials. In this paper the porous materials were manufactured by PCH comparing with hot pressing (HP). The growth model of sintering neck and atom diffusion in the sintering neck was investigated. And the effect of process parameters on the property of porous materials was studied.The size of relative neck increased with increasing holding time, processing temperature, and the decreasing particle size. Effect of holding time on porosity decreased with increasing sintering temperature and increasing particle size. To attain the similar max load stress, the holding time of PCH process was shorter than HP. In addition, there is notable increase in porosity compare with tiny change of yield stress results from the shorter sintering time of the PCH process. The diffusion coefficients increase with increasing processing temperature. At the same sintering temperature, the diffusion coefficient during the PCH process is larger than that of HP. The change of diffusion coefficients influenced by the temperature under PCH is more obvious than that under HP. Atom diffusion under PCH is faster than under radiation heating.The porosity of porous Ti decreased with increasing processing temperature exponentially. The resistance increased with the increasing porosity of samples. Starch soluble is a kind of favorable additives. The porosity of porous Ti increased with increasing content of starch soluble, and maximum load stress of porous Ti reduced with the increasing porosity accompany with the rise of maximum extension.