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Lead-calcium grids

Even higher tin contents (up to 2wt.%) have been reported [89] to provide reduction in the rate of corrosion and growth of positive lead-calcium grids in VRLA batteries employed in standby service at elevated temperatures. The beneficial effects of high tin on positive-grid corrosion in VRLA batteries have recently been confirmed [90]. It is proposed that the improved corrosion resistance is due to the large number of fine precipitate particles and better accommodation of the stresses of corrosion by the high mechanical properties of the alloys. [Pg.25]

Some decades ago, when lead-acid batteries with positive lead-calcium grids without antimony were first placed on the market, there was a major disaster in terms of very poor cycle-life. Investigation of the phenomenon revealed that the cause of the failure was the formation of a barrier layer of lead sulfate between the... [Pg.444]

Table 4.2 presents a summary of the lead alloys most widely used for the production of various types of lead—acid batteries [5]. Lead—antimony and lead—calcium grid alloys have dominating positions in the battery industry. The basic characteristics of these two types of alloys and their effects on battery performance will be discussed further in this chapter. [Pg.152]

At the end of the twentieth century, maintenance-free VRLA batteries were invented. The first VRLA batteries employed lead—calcium grids. The antimony-free effect exhibited fully, which forced metallurgists to switch back to Pb—Sb alloys for the positive grids, minimising... [Pg.178]

A semiconductor mechanism was proposed for the electrocatalytic action of tin on the oxidation of PbO to PbO and Pb02. Tin has substituted antimony as an additive to the alloys for lead—acid battery grids. It is added in considerably lower concentrations than Sb and in combination with calcium which improves the mechanical properties of the alloys. Thus the interface problem of lead—calcium grids was resolved and the way was open for the manufacture of maintenance-free wet-charged batteries. [Pg.561]

WROUGHT LEAD-CALCIUM GRID WITH PLASTIC BOTTOM BORDER RESTING ON PLAT CASE BOTTOM IS STRONG, ELECTRICALLY EFFICIENT AND CORROSION RESISTANT... [Pg.602]

The use of antimony in grid alloys has become associated with operating problems such as battery water loss and self-discharge, which lowers battery life and raises maintenance requirements. The commercial Introduction of lead-calcium grids in the... [Pg.118]

Rea.ctivity ofLea.d—Ca.lcium Alloys. Precise control of the calcium content is required to control the grain stmcture, corrosion resistance, and mechanical properties of lead—calcium alloys. Calcium reacts readily with air and other elements such as antimony, arsenic, and sulfur to produce oxides or intermetaUic compounds (see Calciumand calciumalloys). In these reactions, calcium is lost and suspended soHds reduce fluidity and castibiUty. The very thin grids that are required for automotive batteries are difficult to cast from lead—calcium alloys. [Pg.59]

Lead—Calcium-Tin Alloys. Tin additions to lead—calcium and lead—calcium—aluminum alloys enhances the mechanical (8) and electrochemical properties (12). Tin additions reduce the rate of aging compared to lead—calcium binary alloys. The positive grid alloys for maintenance-free lead—calcium batteries contain 0.3—1.2 wt % tin and also aluminum. [Pg.59]

Wrought lead—calcium—tin alloys contain more tin, have higher mechanical strength, exhibit greater stabiUty, and are more creep resistant than the cast alloys. RoUed lead—calcium—tin alloy strip is used to produce automotive battery grids in a continuous process (13). Table 5 Hsts the mechanical properties of roUed lead—calcium—tin alloys, compared with lead—copper and roUed lead—antimony (6 wt %) alloys. [Pg.59]

FMl. Replacement of lead antimony alloys with lead-calcium alternatives, as a means to discourage hydrogen evolution, reduces the creep strength of grids so that expansion in the plane of the plate may again become a concern. Use of a separator with insufficient rigidity (i.e., too much compressibility ) may allow expansion normal to the plane of the plate. [Pg.10]

Hardening mechanism in lead-calcium alloys. Lead-calcium alloys harden extremely rapidly 80% of the ultimate strength is reached in one day, and virtually full ageing in seven days. Such rapid hardening enhances grid handling and battery production. The rapid hardening was a benefit to VRLA batteries. [Pg.17]

Silver additions to lead-calcium-tin alloys. Silver has been added to lead-calcium-tin alloys to increase the resistance to creep and corrosion, and to prevent growth of the positive grids at elevated temperatures. Valve-regulated lead-acid batteries often operate at elevated temperatures and/or produce high internal... [Pg.28]

Silver is reported to segregate to the grain and sub-grain boundaries of lead-calcium-tin alloys [94]. Microprobe analysis of the cross-section of grid wires produced from cast and rolled lead-calcium-tin alloys with a bulk silver content of... [Pg.31]

See other pages where Lead-calcium grids is mentioned: [Pg.57]    [Pg.17]    [Pg.18]    [Pg.312]    [Pg.178]    [Pg.179]    [Pg.555]    [Pg.548]    [Pg.569]    [Pg.57]    [Pg.17]    [Pg.18]    [Pg.312]    [Pg.178]    [Pg.179]    [Pg.555]    [Pg.548]    [Pg.569]    [Pg.59]    [Pg.62]    [Pg.577]    [Pg.736]    [Pg.737]    [Pg.737]    [Pg.198]    [Pg.253]    [Pg.147]    [Pg.148]    [Pg.577]    [Pg.9]    [Pg.15]    [Pg.15]    [Pg.17]    [Pg.20]    [Pg.24]    [Pg.24]    [Pg.25]    [Pg.30]    [Pg.31]    [Pg.31]    [Pg.32]   
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Antimony lead calcium grids

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