For many years it has been popular to add antimony to lead alloy which is eventually cast to produce battery grids. These grids essentially consist of a lattice of thin lead struts which are textured on their surfaces to subsequently engage and hold lead oxide pastes which are applied thereto. In the past, it has been known that approximately 3% antimony in a lead alloy is suitable to increase the strength of that alloy and to provide certain other characteristics which are desirable in battery grids. One of the disadvantages of utilizing such a percentage of antimony is that the antimony itself is an impurity with respect to the chemical reactions which take place in the battery, and therefore, the antimony content of the lead grids is responsible for numerous chemical or electro-chemical side effects which are undesireable.
In particular "high" percentages of antimony in lead alloys used to cast battery grids are believed to directly affect the amount of "gassing" which is experienced when a battery is subjected to overcharge conditions. Once a battery which has been discharged is charged to approach a "full charge" condition there will be a tendency for water in the sulfuric acid solution to disassociate through electrolysis into hydrogen (H.sub.2 .uparw.) and oxygen (O.sub.2 .uparw.) gas. This electrolysis is believed to be catalyzed directly in proportion to the amount of antimony, i.e. the percentage of antimony, which is contained in the grid alloy material.
Recently, attention has been directed by the battery industry to reducing the tendency of a battery to "gas" during overcharge conditions so that water need not be added to that battery during the normal operating life thereof. These batteries are now commonly referred to by the battery industry as "maintenance free" batteries.
Since the above described phenomena relating to antimony and its effects on "gassing" is well documented in the prior art, one common approach of the battery industry to reduce the "gassing" of a battery is the reduction or elimination of antimony from the battery grid alloy. For example, it has long been known that alloys with antimony contents in the range of 2.25-2.75 wt-% will reduce gassing while retaining other properties which produce suitable battery grids, particularly in lead alloys with other amounts of standard battery grid materials such as tin (0.25-0.50 wt-%), arsenic (0.15% maximum), copper (0.04-0.06 wt-%) and sulfur (0.003-0.01 wt-%), (the remainder being lead).
One of the problems which is encountered in casting with a relatively lower antimony battery grid alloys is that the surface tension of such an alloy is somewhat greater than the surface tension normally encountered with the higher antimony-containing lead alloys. Since surface tension is an important factor in filling the molds for relatively thin lattice - like grids, the use of low-antimony grid alloys, while reducing somewhat the degree of "gassing" of the battery, brings with it other difficulties which may adversely affect the manufacturing cost of the resultant grids and the quality of the end product produced therefrom.