Preparation Of Porous Titanium And Characterization Of Its Pore Structure

Titanium metal has the characteristics of low density, high strength, wide working temperature range, good corrosion resistance and good biocompatibility.Porous metal titanium not only has the properties of titanium metal, but also has the properties of metal foam, which can reduce the weight of the material without damaging its strength. Therefore, the excellent performance of porous titanium which has wide application prospect in some special fields.Preparation methods, structures and properties have been a research hotspot nowdays.This paper proposes a new preparation concept for porous metallic-titanium by in-situ reduction of porous titanium oxides. firstly titanium oxide with a certain pore structure was prepared, then reduced by calcium vapor and leaching,lastly we can get the porous metal titanium. In this paper, we use XRD, SEM, EDS and other modern testing means and methods. The types of pore forming agent, the adding amount of pore forming agent and the sintering temperature were studied. And porous titanium with a certain pore structure was prepared by the method of calcium thermal reduction.Porous TiO2 research results show that:with the increase of pore forming agent,the porosity of the porous titanium dioxide increases; and the porosity of citric acid as the pore forming agent to prepare the porous TiO2>porosity of starch as the pore forming agent to prepare the porous TiO2>porosity of graphite as the pore forming agent to prepare the porous TiO2. Increased from 800℃ to 900℃ in the sintering temperature, the porosity of samples increased but the increase was slow, when the sintering temperature continues to rise, increased from 900℃ to 1100℃, the porosity decreased gradually. Starch as pore forming agent, can obtain more uniform pore size distribution. The porosity of starch as pore forming agent was characterized by using mercury mercury analyzer. The results were that:the sample had a microporous structure, and the pore throat radius was concentrated in 0.25～0.63 μm. After adding pore forming agent, the pore throat radius is more than 10μm，and the pore size of titanium dioxide increases with the increase of pore forming agent. With the increase of temperature, the pore throat radius of the sample has a decreasing trend, and the proportion of the large hole in the sample 25 μm has decreased.The porous titanium dioxide can be obtained by adding calcium chloride and titanium dioxide to vacuum sintering. And the porosity of the samples increased with the increase of the amount of calcium chloride. During the sintering process, the titanium dioxide is converted to calcium titanate, but the size and uniformity of pores are difficult to control.Porous titanium dioxide is reduced to obtain the porous titanium. The research results show that:on the one hand we can get porous titanium with a certain pore structure using starch as the pore forming agent. and with the increase of the porosity of the porous titanium dioxide, the pores of porous titanium surface were increased. After the leaching calcium oxide is removed, the porous structure collapsed. On the other hand,sintered samples which use calcium chloride were calcium thermal reduction. Samples can be reduced to metallic titanium,and part of the titanium particles in reducing aggregation into the porous layer and obvious trend of sintering connection, but when removal of calcium oxide, porous structure collapse, the most titanium present powder, granular, and it is difficult to retain porous skeleton.