Very fine metal, oxide or cpd. powder prodn. - by heating organic solvent soln. or suspension of inorganic salt or complex, used e.g. for high temp. superconductor

摘要

Prodn. of very fine powders (I) of metal, metal oxide, metal cpd. or mixts. of these is carried out as follows. The starting material consists of inorganic metal salt(s) (II), which can be dissolved or suspended in organic solvent (mixts.) or transferred from aq. soln. into a water-immiscible organic phase in an organic chelating agent (III). (III) is an oxa-, aza or oxaazalkane (mixt.), in which the O and/or N hetero-atoms are sepd. by a no. of -CH2- gps. and the terminal gps. are OH, cycloalkyl and/or linear and/or branched 4-18C alkyl gps. (II) are dissolved and homogenised in a high-boiling, chemically stable organic solvent (mixt.) (IVA) or in (III) if this is also (IVA). Alternatively, aq. (ii) solns. are contacted with a water-immiscible (III) and with a water-immiscible organic solvent (IVB) or with (III) if this is also (IVB), then the resultant metal complex cpds. are sepd. from the aq. phase. During or after dissolution and/or homogenisation or after contact, the organic solns. or suspensions are heated at a heat-up rate of 1-20 K/min. to a temp. between 150 deg.C and the lowest b.pt. of the components and opt. held at a temp. in this interval, then cooled, and the solid sepd. from the liquid after or during cooling. USE/ADVANTAGE - (I) are useful, e.g., as precursors for high temp. superconductors or other functional ceramics. They have high chemical purity and are homogeneous, even in the micro-range. The process uses simple technololy, making it cheaper than usual