What type of nail or spike do you use to halt production of fruit in a walnut tree?

My walnut tree produces 130 bushles of nuts every few years. I don’t wish to cut down the tree. I would prefer to lower or stop production of fruit instead. I heard that by driving nails or spikes into the trunk can slow or stop fruit production. What alloy does the spike have to be? brass,bronze,copper,iron,stainless,zinc ect…