Selection Of Preparation Method And Their Experimental Investigation Of Porous Lead

Because the porous lead has larger porosity and specific surface area, it is used as a lead-acid battery grid material can fill more of the active substances that increase the capacity of the battery. Further, when the porous lead is used to produce electrolytic zinc anode material, larger surface area to reduce current density, thereby reducing the oxygen evolving anode over potential. Therefore, it has great practical significance for the preparation and properties of the porous lead.In this paper, prepared porous lead in the three methods (melt foaming, powder metallurgy, flow casting method) have been studied to explore, and focus on the flow casting method studies. The paper carries out the static compression performance of porous lead that has different characteristic parameters (diameter and relative density) and electrical performance testing and analysis. The main results obtained are as follows:Firstly, in the flow casting method precast blocks broken rate increases with pressure. When broken rate is 10%, particle size 1.18-11.7,1.7-2.36,2.36-3.35mm of NC-type space holder molding pressure are respectively 12.5,8.5,5MPa. Precast block orthogonal experimental results show the sintering process that the factors from high to low affect the size of the porosity is pore diameter, compacting pressure, sintering time, sintering temperature of the NC type.Secondly, choosing KS type pore-forming agent to produce the porous lead in the flow casting method, according to the principles of heat transfer calculated pore-forming agent preheat temperature and lead pouring temperature relationship is; according to the principle of capillary calculated applied pressure and melt temperature relationship is. According to the above formula and compared with the appropriate parameters to measure the length of the test flow is obtained:Lead liquid temperature 420℃, pore forming agent preheating temperature 280℃, pressure 0.06-0.08MPa. By using different particle porogen was prepared a porosity of 58% -67% of the porous lead.Thirdly, the static compression testing shows that with the increase of the relative density the compressive strength and elastic modulus of the porous lead increases gradually; the cube porous structure model shows that:when the pore size are 1.25mm,1.85mm and 2.85mm, the C2 values are 0.8927,0.8242 and 0.9627 and the n values are 1.4521,1.3665 and 1.5014, then get the cubic porous structure model fitting with different pore sizes. In the same relative density, the impact of the pore size is small for compression performance of the porous lead.Finally, the porous lead conductivity test shows that:with the increase of relative density, the conductivity increases of the porous lead. According to percolation theory model, we performed a fit. And Variation of conductivity with the relative density of the porous lead complies with exponential relationship. When the pore size is 1.25mm,1.85mm and 2.85mm, fit index nare 1.6115,1.5735,and 1.5388. And so get different aperture exponential equation. In substantially the same relative density, conductivity of the porous lead decreases with the decreasing of pore size.