Microstructural Analysis and Corrosion Behavior of a Titanium Cenosphere Composite Foam Fabricated by Powder Metallurgy Route

This study examines the influence of cenosphere particle size and sintering parameters on the microstructure and electrochemical behavior of Ti-cenosphere composite foam fabricated by powder metallurgy route. Cenosphere has been added as a space holder material to develop Ti composite foam because of its abundant availability and low cost. Ti (particle size between 250 mu m and 350 mu m) and cenosphere (with a varying particle size of <150 mu m, 150 mu m-200 mu m and >200 mu m) in the ratio of 75 : 25 (wt %) were compacted using 100 MPa of applied pressure and sintering temperatures of 1000 and 1200 degrees C with sintering time ranging from 2 to 6 h at a heating rate of 25 degrees C/min. A defect-free microstructure with the uniform dispersion of cenosphere particles in the Ti matrix was observed with the cenosphere particles in the size range of 150-212 mu m at a sintering temperature of 1000 degrees C for 4 h. The porosity content in the syntactic foam varied from 34 to 50 % and decreased with increasing sintering time and temperature. Based on a detailed study of corrosion behavior in Hank's solution, the composite foam with cenosphere particles in the size range of 150-212 mu m and sintered at 1000 degrees C for 4 h showed the highest corrosion resistance.