Abstract: A refractory ceramic material possessing a solidus temperature between 2500° C. and 2800° C., having a compactness greater than 85%, and a microstructure such that the material is composite of: (a) hafnium dioxide HfO2 grains having a monoclinic structure (1); (b) hafnium dioxide HfO2 grains having a cubic structure (2) which is stabilized by yttrium oxide Y2O3, the yttrium oxide Y2O3 representing 0.5 mol % to 8 mol % relative to the total number of moles of hafnium dioxide HfO2; (c) closed pores (3); (d) non-interconnected open pores. The process of manufacturing the material and a structural part incorporating the material are also set forth.

Abstract: A powder metallurgy process for the manufacture of powders of a refractory ceramic material, comprising the consecutive steps of: (i) obtaining a dry mixture of a hafnium dioxide HfO2 powder and an yttrium oxide Y2O3 powder; (ii) step of granulation by pelletization of the dry mixture under stirring in order to obtain a granulated mixture, this granulation step comprising the spraying, into the dry mixture, of an aqueous solution comprising polyvinyl alcohol (PVA) and polyethylene glycol (PEG); (iii) drying of the granulated mixture; (iv) filling of a mold with said granulated mixture; (v) isostatical or semi-isostatical pressing of the granulated mixture in order to obtain a compact mixture; (vi) sintering of the compact mixture in order to obtain a refractory ceramic material at a solidus temperature in the range between 2500° C. and 2800° C.

Abstract: A powder metallurgy process for the manufacture of powders of a refractory ceramic material, comprising the consecutive steps of: (i) obtaining a dry mixture of a hafnium dioxide HfO2 powder and an yttrium oxide Y2O3 powder; (ii) step of granulation by pelletization of the dry mixture under stirring in order to obtain a granulated mixture, this granulation step comprising the spraying, into the dry mixture, of an aqueous solution comprising polyvinyl alcohol (PVA) and polyethylene glycol (PEG); (iii) drying of the granulated mixture; (iv) filling of a mold with said granulated mixture; (v) isostatical or semi-isostatical pressing of the granulated mixture in order to obtain a compact mixture; (vi) sintering of the compact mixture in order to obtain a refractory ceramic material at a solidus temperature in the range between 2500° C. and 2800° C.

Abstract: A refractory ceramic material possessing a solidus temperature between 2500° C. and 2800° C., having a compactness greater than 85%, and a microstructure such that the material is composite and comprises: hafnium dioxide HfO2 grains having a monoclinic structure (1); hafnium dioxide HfO2 grains having a cubic structure (2) which is stabilized by yttrium oxide Y2O3, the yttrium oxide Y2O3 representing 0.5 mol % to 8 mol % relative to the total number of moles of hafnium dioxide HfO2; closed pores (3); non-interconnected open pores. The invention also relates to the process of manufacturing said material and a structural part incorporating said material.