Catalytic effect of silver addition on the low temperature phase formation ofMgB2

Abstract

A small amount of silver addition was found to dramaticallydecrease reaction temperature of magnesium and boron forming theMgB2 bulk without degradations in both critical temperature and critical current properties. A sample with∼3% silver addition formagnesium heated at 550 °C for 72 h recorded a high Jc above 2 × 105 A cm−2 at 20 K in low fields reflecting its strongly grain-coupled microstructure. In addition, a sample with∼5% silver additionshowed Jc of∼1 × 105 A cm−2 at 20 K in low fieldseven for heating at 500 °C for 72 h. Although the added silver formed Ag–Mg alloy after the heat treatment,these impurity particles mainly existed at the edge of voids without losing theeffective current path. Our present results will contribute to developing low costMgB2 conductors.