Low-temperature sintering to fabricate MgB2 by using Mg(BH4)2 as precursor

Low-temperature sintering to fabricate MgB2 is considered a promising method because it reduces the formation of MgO and reduces the grain size, thereby increasing the critical current density. Chemical doping, ball milling of precursor and modifying the Mg source in precursor for low-temperature sintering have all been carefully investigated. However, the threshold of sintering temperature have been kept near 500 degrees C. A new in-situ method to low-temperature sintering using Mg(BH4)(2) as a precursor is presented in this paper. Mg(BH4)(2) decomposes into highly reactive nanoscale Mg and B in a molar ratio of 1:2 without impurities. In this method, only 2 h of sintering at 400 degrees C is required to completely react Mg with B to produce MgB2, and after 54 h sintering, the sample has comparable J(C) to the normal MgB2 from solid-state reaction method sintered at 800 degrees C. The sample sintered at 500 degrees C give better J(C) than normal MgB2 under both high and low magnetic field.