What is lead antimony alloy?

Lead-antimony alloy is an antimony-containing lead alloy used in the manufacture of lead-acid battery grids and conductive parts. Compared with pure lead, it has a lower melting point, good fluidity in molten state, easy casting and molding, and high hardness after solidification; the disadvantage is that the gas evolution overpotential of the grid is low. In order to reduce the precipitation of gas during charging of the battery, reduce self-discharge and improve corrosion resistance, the antimony content has been gradually reduced from the traditional 5% to 7% to about 2% or even lower. At the same time, a small amount of other components such as tin, arsenic, sulfur, selenium and copper are selectively added to improve the physical and chemical properties of the alloy.

Lead-antimony alloys are widely used in national production. However, it is quite difficult to separate lead-antimony alloys to produce lead-antimony. This is because lead and antimony have similar physical and chemical properties and behave similarly in metallurgy. For a long time, researchers at home and abroad have carried out many explorations, such as centrifugal segregation method, vacuum distillation method, electrolysis method, etc.

Determination of lead in lead antimony alloy

Alloys containing lead and antimony have a small friction coefficient, good toughness, thermal conductivity and corrosion resistance, and are the preferred materials for the production of battery plates, chemical pipes, and cable sheaths. Compared with pure lead, lead-antimony alloy has low melting point, good fluidity in molten state, easy casting and high hardness after solidification. 

Since the lead-antimony alloy is prepared with reduced lead, the performance indicators of the alloy have a great relationship with the lead content, and the related lead determination methods are rarely reported in the literature. Dissolve the sample with sulfuric acid-potassium sulfate system, use sodium citrate as masking agent, and use lead sulfate precipitation method to separate and remove the interference of antimony, iron, zinc, tin, copper, aluminum, cobalt, nickel, manganese and other elements, at pH=5.5 The lead content in the alloy was determined by EDTA titration method.

Uses of lead-antimony alloys

Lead-antimony alloy is a lead-based alloy, which is mainly used as an alloy material for sliding bearings, that is, bearing bushes. It is based on lead, adding tin, antimony, copper and other alloying elements, such as zchpbsb 16-16-2, which means that the main additive element antimony content is 16%, the auxiliary additive element tin content is 16%, and the copper content is 2% . Among them, lead is present in the form of a soft matrix, while antimony is a hard point metal compound SnSb. The upper has a large friction coefficient and low impact resistance, but the price is low. It is used for bearings with medium speed and medium load, no obvious impact load, and working temperature does not exceed 120 degrees Celsius. Such as bearings for motors, crushers, compressors, etc.