Hot isostatic pressing of Chevrel phase bulk and hydrostatically extruded wire samples

In order to lower final sintering temperatures for Chevrel phase (CP) wires, we have investigated low-temperature hot isostatic pressing (HIP'ing) of both bulk and wire samples. We have fabricated (Pb,Sn)-based Chevrel phase (CP) monofilament and 61 filament wires by hydrostatic extrusion of (Cu or Cu-Ni)/(Nb or V)/CP composites, followed by cold drawing. We have investigated the CP/barrier reaction during heat treatment, finding V is unsuitable, but Nb is suitable at these lower temperatures for prereacted Pb/sub 1-x/Sn/sub x/Mo/sub 6/S/sub 8/ cores. We prepared powders of the binary Chevrel phase Mo/sub 6/S/sub 8/ by acid leaching of Li/sub x/Mo/sub 6/S/sub 8/ and Ni/sub x/Mo/sub 6/S/sub 8/. We prepared bulk samples of PbMo/sub 6/S/sub 8/ and Pb/sub 1-x/Sn/sub x/Mo/sub 6/S/sub 8/ by HIP'ing mixtures of "Pb+Mo/sub 6/S/sub 8/" powders (in situ route) or by prereacting Pb, Sn and Mo/sub 6/S/sub 8/ powders before HIP'ing (prereacted route). The in situ powders were HIP'ed under different time-temperature-pressure conditions up to 12 h/600/spl deg/C/200 MPa, producing partially consolidated PbMo/sub 6/S/sub 8/ samples. Further HIP'ing of all samples at temperatures of 700, 800 and 1000/spl deg/C, 200 MPa pressure and times of 8 and 80 hours produced additional consolidation, up to 95% of full density. As the aggressiveness (temperature and time under pressure) of the HIP process increased, the density, hardness, critical temperature, and magnetization critical current density increased.<
>