Zirconium tin titanate compositions, ceramic bodies comprising same, and methods of manufacturing same

A microcracked ceramic body, comprising:

• a predominant phase of zirconium tin titanate;
• a microcrack density;
• and
• a dilatometric coefficient of thermal expansion (CTE) from 25 to 1000° C. of not more than 40×10−7° C.−1 as measured by dilatometry;
• and
• a zirconium oxide-based baddeleyite phase that contains at least tin and titanium in solid solution, wherein the baddeleyite phase is characterized by a phase transformation from a monoclinic phase at low temperature to a tetragonal phase at higher temperature and wherein the transformation occurs below 1000° C.

A method of manufacturing a microcracked ceramic body, comprising:

• providing an inorganic batch composition comprising a zirconium oxide powder, a titanium oxide powder, and a tin oxide powder, wherein the median particle size of at least two of the oxide powders is at least 5 μm and wherein the sum of the weight percentages of the zirconium oxide powder, titanium oxide powder, and tin oxide powder is sufficient to provide more than 50 weight percent of a zirconium tin titanate phase in the microcracked ceramic body;
• mixing the inorganic batch composition together with one or more processing aid selected from the group consisting of a plasticizer, lubricant, binder, pore former, and solvent, to form a plasticized ceramic precursor batch composition;
• shaping the plasticized ceramic precursor batch composition into a green body;
• and
• firing the green body under conditions effective to convert the green body into the microcracked ceramic body comprising:
• greater than 50 wt % of the zirconium tin titanate phase,
• wherein the mol % of each of ZrO2, SnO2 and TiO2 components in the zirconium tin titanate phase is expressed as 40≤Z≤65, 13≤S≤50, and 5≤T≤30, where Z=100(mol % ZrO2)/(mol % ZrO2+mol % SnO2+mol % TiO2), S=100(mol % SnO2)/(mol % ZrO2+mol % SnO2+mol % TiO2), and T=100(mol % TiO2)/(mol % ZrO2+mol % SnO2+mol % TiO2);
• wherein a minimum lattice axial CTE (CTEmin) from 25 to 1000° C. of the zirconium tin titanate phase is not more than 30×10−7° C.−1;
• and
• wherein a zirconium tin titanate grain size parameter, g, in units of micrometers (μm) fulfills the expression g≥k2[4.15+1.99×106(CTEmin)+3.58×1011(CTEmin)2+2.15×1016(CTEmin)3], wherein k2≥1, CTEmin is in units of ° C.−1, and the grain size is determined by a line intercept method applied to an image of the ceramic microstructure and is defined as g=L/p where p is the number of grain boundaries intercepted by one or more straight lines of total length L or one or more circles of total circumference L, wherein L is in units of micrometers and L is chosen such that the value of L/g is at least 25 in order to provide adequate counting statistics for calculation of the grain size parameter.