A STUDY ON THE POROUS TITANIUM COMPACTS HAS A VERY HIGH QUALITY

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In this study, sintering behavior, the amount and configuration of pores and the permeability in sintered titanium compacts have been investigated. The porous compacts were prepared from titanium powder coated with nickel by chemical plating method. The sintering was carried out at 950-1100ﾟC which is obviously above eutectic temperature in the Ti-Ni system. Therefore, all powders were covered with liquid phase which was formed during the sintering.(1) Remarkable shrinkage occurs at eutectic temperature of 950ﾟC for the Ti-Ni composite powder compacts resulting from the rearrangement of powder particles in assistance with the liquid phase.(2) In this sintering process, connecting the open pores with closed pores easily proceeds owing to the good wetting ability of the liquid phase formed at eutectic temperature. The amount and configuration of pores in the sintered compacts are determined at the same time when the rearrangement of powder particles is completed. Only a little change is expected on further sintering.(3) The permeability of the sintered compacts increases proportionally with increasing the quantity of nickel plated between 7 and 15wt%Ni and the most desirable porous compacts having the largest permeability, suitable size and configuration of pores can be obtained in the composite powder compact containing 15wt%Ni in spite of the decrease in porosity.(4) Corrosion resistance of this compacts against 10%HCL and H_2SO_4 is better than that of CP titanium compacts but the one against 10%HN_3 is a little bit worse.