In the discussion before lead acid lithium battery plate grid alloy used in industry, must be discussed in more detail the alloy phase diagram.
Lead antimony alloy, the variation of antimony content, alloy solidification point (
Different, if the measure of lead antimony alloy of antimony content in a range of different freezing point (
Ordinate, antimony content in the alloy as the abscissa mapping, in order to study the phase diagram is convenient, the alloy liquid (
The molten body)
System, the physical and chemical properties and composition of uniform section called 'phase', such as liquid phase and solid phase.
Phase diagram refers to a variety of alloy with the temperature change of a change in its state diagram.
In the lead antimony alloy phase diagram, a known as a solid solution.
A solid solution of lead antimony more little, melt with small amounts of antimony in the lead.
P called day is solid solution, the solid solution of antimony, lead more less, the molten lead a small amount of antimony.
See from the lead antimony alloy phase diagram, when the antimony content of 13%, the freezing point of minimum lead antimony alloy.
Less than 13 weft, antimony alloy from L (
The liquid phase)
The temperature dropped to freezing point, the first in a solid solution, the temperature continues to fall to C/E/D area alloy appeared a p facies.
In the production practice, sheeting need small crystals evenly.
Slab gate to keep certain cooling speed can obtain the tiny crystal grain,.
Solid solution containing antimony quantity decrease with temperature decrease, there are 2 at the beginning of the antimony content.
5%, continue to cool to antimony content is about 0.
If 4% of the temperature, cooling speed too fast, Q solid solution can not afford time to change has become a solid phase, at this time.
Solid solution is not stable, some antimony precipitation in solid solution in the form of p solid solution, at the same time because of difficulties in the solid phase diffusion.
Solid solution and the uneven distribution of p solid solution, crisp sheeting enough.
The other in the board's ear (
Or thick steel)
For alloy liquid capacity is much, cooling is relatively slow, also easy to cause local antimony content too much, 'white spot' and even crack.
Antimony content in the alloy is reduced, 'cracking' the greater the tendency, so the production of plate grid is brittle.
Into the coarse grain structure, this is due to the solidification and contain hot crack, and distribution along the grain boundary.
Low antimony alloy cracking phenomenon can be avoided, usually add crystalloblastic agent (