Controlled chemical doping of magnesium diboride (MgB2) has been shown to substantially improve superconducting properties to the levels required for high field magnets, but consistent dopant concentrations and homogeneity are difficult to accomplish through the usual route of solid state reaction and diffusion. Furthermore, a high quality source of doped boron needs to be established to advance the state of the art and to ultimately commercialize MgB2 superconductors. Gas phase plasma synthesis of boron powder in which dopants and boron are atomically mixed in the plasma will produce nano-sized batches of doped boron powder. Initial experiments using plasma synthesis methods proved satisfactory to prepare carbon-doped boron powders suitable for the fabrication of high performance MgB2 conductors. At 20 K, critical current density (Jc) values of 100,000 A/cm2 were obtained at 2 Tesla and at 5 K, Jc values of 100,000 A/cm2 were obtained at 4-5 Tesla. Upper critical magnetic field (Hc2) values as high as 37 tesla were achieved. In Phase I, an investigation of carbon, titanium, and silicon carbide as dopant additions to boron powder will be carried out to improve on the above properties. The plasma synthesis method will be used for powder production and the effect of dopant chemistry and concentration on the properties of boron powder will be examined. Doped boron powder will be converted to MgB2 superconducting pellets and powder-in-tube wires, and the superconducting properties will be measured. The effect of powder particle size, purity, dopant concentration, and chemical homogeneity on the superconducting properties of MgB2 will be investigated. Chemically doped magnesium diboride (MgB2) superconducting magnets can perform at least as well as NbTi and NbSn3 in high field magnetic fields and still offer an improvement over the latter in terms of operating temperature. These characteristics make doped MgB2 an effective material for medical MRI devices. Cheaper and more efficient medical MRI devices could lower examination costs, find potential health problems earlier, and thus benefit society as a whole. ? ? ?
