The development of an infiltrated lead/iron composite material for use as a non-toxic bird shot

Abstract

The infiltration of sintered, porous iron powder masses by lead does not occur very readily; it has been shown in this work that the process is highly temperature dependent. Calculations show that only a marginal decrease in the contact angle below 90° is required to allow complete wetting to take place. The calculated contact angles between lead and iron are significantly higher than values reported in the literature, probably due to oxide contamination of the powder surface. The addition of zinc to the lead rich phase allows infiltration by lead or lead alloys to occur more readily; very little zinc remains in the pellet after infiltration. The zinc appears to act as a reducing agent to clean the iron surface of residual oxide and allow wetting to occur. Infiltrated lead iron composites, in the form of spherical pellets, have been shown elsewhere to be an acceptable alternative shot material for waterfowl hunting.