Possibilities of matrix lead alloy doping at non-gasostatic carbon-graphite impregnation

Abstract

The study covers the process of carbon-graphite – lead composite formation by impregnating a porous AG-1500 scaffold with a lead melt containing 2.0 at.% Cu. The paper describes the kinetics of filling the carbon-graphite open porosity with molten metal with the continuously heated furnace and impregnating device. A feature of this method is the volumetric expansion of the lead alloy impregnating porous carbon-graphite. It is placed in a sealed steel container filled with lead by 2/3 of its volume with further vacuuming, melt adding and sealing. Then the device is placed in the furnace so that the lead-copper alloy, already having a temperature below the liquidus temperature by 20–30 °C when heated in the furnace to 900 °C, impregnates the carbon-graphite scaffold with further expansion at constant heating. Porous scaffold capillaries are filled as the melt temperature continuously increases. Once graphite-carbon impregnated with lead alloy is taken out, it was investigated using X-ray spectral and energy-dispersive analysis. It was found that the elements of the impregnating alloy were redistributed at the carbon-graphite scaffold/Pb alloy interface depending on its initial composition. During the carbon-graphite scaffold impregnation with the Pb–2%Сu alloy under a pressure of up to 5 MPa, copper redistribution occurs on its inner pore surface and the boundary with the alloy, which leads to the formation of an interphase layer containing 70 % Cu. The conducted research made it possible to obtain a composite with a copper content of 1.85 at.% in the impregnating Pb alloy at the interface with carbon graphite.