No. 7 alloy is a modification of #3 alloy in which lower magnesium content is specified in order to increase the fluidity. To avoid problems with intergranular corrosion lower levels of impurities are called for and a small quantity of nickel is specified. Alloy #7 has slightly better ductility than #3 with other properties remaining at the same level. The alloy is therefore popular for those special cases where the die caster is making thin walled components requiring a good surface finish. However, research testing has shown that metal and die temperatures have a bigger effect than changing alloys. Close attention to control of the die casting process parameters is important so as to eliminate defects and achieve consistent quality.