A general study of the formation of intermetallic perovskite borides and carbides in the ternary systems AXM3 (A=Mg, Ca, Sc, Y, Lu, Zr, Nb; X=B, C; M=Ni, Ru, Rh, Pd, Pt) is reported. MgBxPd3, MgBxPt3, CaBxPd3, MgC xRh3, LuCxRh3, and ZrC xRh3 represent new intermetallic perovskites that form at a composition that is nominally stoichiometric (x=1). ScBxPd 3, YBxPd3, and NbBxRh3 are new single-phase perovskites that form only at a substoichiometric (x<1) nominal composition. The variable boron content of ABxPd3 (A=Mg, Ca, Sc, Y) was studied using lattice parameter data from X-ray diffraction measurements. For A=Ca and Mg, the unit cell volume increases with increasing boron content for 0.25≤x≤1.0, while boron uptake is limited to 0≤x≤0.5 for A=Sc and Y. Neutron diffraction studies indicate that CaB xPd3 is not actually stoichiometric at a nominal composition of x=1. Rather, saturation of the boron content occurs at CaB 0.76Pd3. Evidence for superconductivity was found in samples of CaBxPd3 (x≥1) and NbBxRh 3, but bulk analysis suggests that superconductivity may be attributed to minority phases.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry