The Effect of Binder and Plasticizer on Porous Titanium Compacts Prepared by Slip Casting

Porous titanium compacts were fabricated using a slip casting technique. The slip casting process is low cost and has the advantage of producing green compacts with open pores. After final sintering the retained porosity gives the material a relatively high permeability. The organic compounds forming the binder and plasticizer are two major components in the slip casting process, which confer binding strength to the powder particles and flexibility in the green compact. In this paper, the effect of the total amount of binder and plasticizer dry weight percent (dw.%) (1.6 dw.% – 8.0 dw.%), when added in a 1:1 ratio, on the properties of porous titanium compacts was investigated. This was done by measuring the gas permeability, pore size and tensile strength of sintered titanium compacts after sintering at 1000oC for 2 hours. More importantly, due to the sensitivity of titanium to oxygen and carbon content, the amount of these impurities remaining in the sintered compacts was also examined. It was found that the maximum content of organic compounds should not exceed more than 4.0 dw.%, otherwise the slip viscosity is too high for it to flow satisfactorily into the mold. The optimum amount of organic additives was found to be 1.6 dw.%, and this produced a compact with an open porosity of 26.3 vol.% and the least amount of residual carbon.