Lead alloys for electric storage battery
AssigneeChloride Group Limited
InventorsJohn McWhinnie, John L. Dawson
Life of this patent
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Abstract
A lead alkaline earth metal alloy comprising lead, calcium, barium or strontium or mixtures thereof in an amount of 0.075A/40% to 0.13A/40% by weight where A is the atomic weight of alkaline earth metal 0.005% to 0.05% magnesium and preferably 0.005% to 0.01% aluminium is disclosed and has improved corrosion resistance combined with tensile strength as compared to alloys with magnesium and aluminium contents outside these defined ranges. The alloy is useful for grids in lead acid electric storage batteries.
Claims8
A lead alkaline earth metal alloy which consists of 0.075A/40% to 0.13A/40% by weight of at least one alkaline earth metal, 0.0001% to 0.1% aluminium, 0.005% to 0.05% by weight magnesium, the balance being lead and impurities, the alkaline earth metal being selected from the group consisting of calcium, strontium and barium and A being the atomic weight of the alkaline earth metal.
A lead alkaline earth metal alloy consisting of 0.075% to 0.13% by weight of calcium, 0.005% to 0.05% by weight magnesium and 0.005% to 0.01% aluminium, the balance being lead and impurities, the alloy having a corrosion loss of less than 85 mg/cm.sup.2 of immersed surface when immersed for four weeks at 30.degree. C. in 5 M sulphuric acid saturated with nitrogen gas as the anode against a mercury/mercurous sulphate reference electrode at a constant potential of 1500 mV.
A lead alkaline earth metal alloy which consists of 0.075A/40% to 0.13A/40% by weight of at least one alkaline earth metal, 0.0001% to 0.1% aluminum, 0.005% to 0.05% by weight magnesium, 0.4 to 0.7% by weight tin, the balance being lead and impurities, the alkaline earth metal being selected from the group consisting of calcium, strontium and barium and A being the atomic weight of the alkaline earth metal.
Dependencies are inferred from the claim text.