| 主权项 |
1. A device for communication by radio waves having frequencies of between 800 MHz and 3 GHz comprising a ceramic housing exposed, at least in part, to the external environment of the device and through which at least a portion of said waves passes during the use of the device, this housing being at least partially composed of a sintered product exhibiting a chemical composition such that, as percentage by weight and for a total of 100%:
32%≦ZrO2≦95%, 1%<Y2O3+CeO2+Sc2O3+MgO+CaO, 0%≦CeO2≦26%, 0%≦MgO≦43%, 0%≦CaO≦37%, 0%≦SiO2≦41%, 0%≦Al2O3≦55%, 0%≦TiO2≦30%, 0%≦lanthanide oxides, except for CeO2≦50%, 0%≦SrO≦24%, 0%≦SiAlON compounds≦50%, other compounds ≦15%, andsaid sintered product comprising, as percentage by weight on the basis of the sintered product and for a total of 100%:
more than 50% of a crystalline part, said crystalline part comprising, as percentage by weight on the basis of the crystalline part and for a total of 100%: more than 40% of a first crystalline phase composed of zirconia, more than 50% by weight of said zirconia being stabilized by means of a stabilizer in a quadratic and/or cubic form, the remainder being in a monoclinic form, optionally, less than 50% of a second crystalline phase composed of a compound chosen from MgAl2O4, XAlmOn, with X chosen from Mg, Ca, Sr, Y, lanthanide oxides and their mixtures, m being an integer such that 10≦m≦12 and n being an integer such that 16≦n≦20, Mg3Al2(SiO4)3, ZrSiO4, yttrium silicates, it being possible for the yttrium to be partially replaced, X2ZSi2O7, with X chosen from Y, lanthanide oxides and their mixtures and Z chosen from Mg, Al and their mixtures, Mg2Al3(Si5AlO18), (Ca,sr)Al2Si2O8, 3(Al2O3)2(SiO2), SiAlON phases, and their mixtures, and optionally less than 10% of a third crystalline phase composed of a compound chosen from oxides of perovskite structure, oxides of spinel structure, oxides of rutile structure FO2, the element F being chosen from the group GF(1) formed by mixtures of tin and vanadium, mixtures of titanium and chromium and niobium, mixtures of titanium and chromium and tungsten, mixtures of titanium and niobium and manganese, mixtures of tin and chromium, and their mixtures, oxides of hematite structure E2O3, the element E being chosen from the group GE(1) formed by mixtures of aluminum and chromium, mixtures of aluminum and manganese, and their mixtures, orthosilicates chosen from the group of zirconium and praseodymium orthosilicates (Zr,Pr)SiO4, zirconium and vanadium orthosilicates (Zr,V)SiO4, zirconium orthosilicates in which iron oxide is found in inclusion, and their mixtures, less than 5% of other crystalline phases, optionally an amorphous part comprising, as percentage by weight on the basis of the amorphous part and for a total of 100%: a first vitreous amorphous phase having the composition XxAlaSibOc with X chosen from Mg, Ca, Sr, Sc, Y, lanthanide oxides, Ti, Zr, Fe, Mn, Co, Cr and their mixtures, x, a, band c being integers such that x+a>0, c>0, b>0, a/b≦2 and x/b≦1, less than 10% of other amorphous phases,the sum of the contents by weight of second crystalline phase and of first amorphous phase being greater than 10% and less than 50%,a SiAlON phase being a phase observing one of the following formulae:
SitAlwOuNv, in which: t is greater than or equal to 0 and less than or equal to 1, w is greater than or equal to 0 and less than or equal to 1, u is greater than or equal to 0 and less than or equal to 1, v is greater than 0 and less than or equal to 1, t+w>0,t, w, u and v being stochiometric indices standardized with respect to the highest one, rendered equal to 1;
MesSi12−(q+r)Al(q+r)OrN16−r, with 0≦s≦2, Me a cation chosen from cations of lanthanides, Fe, Y, Ca, Li and their mixtures, 0≦q≦12, 0≦r≦12 and q+r≦12. |
