(DE4116732-A)      Prodn. of porous ceramic parts in which a mixt. (I) is produced contg. ceramic powder and binders moulding and sintering comprises    (a) forming (I) using an unstable ZrO2 or Zr(CO3)2 and a non-oxidic cpd., which can decompose to form a gas and is stable to ZrO2, e.g. CaCO3;    (b) moulding to give ceramic parts; and    (c) heating the parts to sintering temp., in which during heating, calcination to produce pores occurs, and then sintering.    Extruded ceramic mouldings are produced by: (a) producing a powder mixt. contg. ZrO2 and CaCO3; (b) adding organic extrudant, e.g. ethylene glycol and methyl cellulose and water, to the mixt. and processing to a plastic extrudable mass; (c) forming a moulding; (d) pre-drying the moulding in hot air; (e) heating the moulding to approx. 1550 deg.C by 1-2 deg.C/min. and keeping at the temp. for 3-10 secs.; (f) cooling the moulding to room temp. by 3-5 deg.C/min.    USE/ADVANTAGE -   The ceramic parts provided are used for fuel cells. They have improved porosity and mechanical strength    (EP514841-A3)      Prodn. of porous ceramic parts in which a mixt. (I) is produced contg. ceramic powder and binders moulding and sintering comprises (a) forming (I) using an unstable ZrO2 or Zr(CO3)2 and a non-oxidic cpd., which can decompose to form a gas and is stable to ZrO2, e.g. CaCO3; (b) moulding to give ceramic parts; and (c) heating the parts to sintering temp., in which during heating, calcination to produce pores occurs, and then sintering.    Extruded ceramic mouldings can be produced by (a) producing a powder mixt. contg. ZrO2 and CaCO3; (b) adding organic extrudant, e.g ethylene glycol and methyl cellulose and water, to the mixt. and processing to a plastic extrudable mass; (c) forming a moulding; (d) pre-drying the moulding in hot air; (e) heating the moulding to approx. 1550 deg.C by 1-2 deg./min. and keeping at the temp. for 3-10 secs.; (f) cooling the moulding to room temp. by 3-5 deg.C/min.    USE/ADVANTAGE -   The ceramic parts produced can be used for fuel cells. They have improved porosity and mechanical strength.