Method for producing aluminum titanate sintered compact

Abstract

The present invention provides a raw material composition for preparing a sintered body of aluminum titanate, the composition comprising (i) 100 parts by weight of a mixture comprising 40 to 50 mol % of TiO 2 and 60 to 50 mol % of Al 2 O 3 , (ii) 1 to 10 parts by weight of an alkali feldspar represented by the formula: (N x K 1-x )AlSi 3 O 8 (0≦x≦1), and (iii) 1 to 10 parts by weight of at least one Mg-containing component selected from the group consisting of a Mg-containing oxide with spinel structure, MgCO 3 and MgO, and a process for preparing a sintered body of aluminum titanate comprising sintering a formed product prepared from the raw material composition at 1300 to 1700° C. According to the present invention, a sintered body of aluminum titanate having high mechanical strength and ability to be stably used at high temperatures, as well as its inherent properties of low coefficient of thermal expansion and high corrosion resistance, can be obtained.

1. A raw material composition for preparing a sintered body of aluminum titanate, the composition comprising:
 (i) 100 parts by weight of a mixture comprising 40 to 50 mol % of TiO 2  and 60 to 50 mol % of Al 2 O 3 , 
 (ii) 1 to 10 parts by weight of alkali feldspar represented by the formula: (Na x K 1-x )AlSi 3 O 8  (0≦x≦1), and 
 (iii) 1 to 10 parts by weight of at least one Mg-containing component selected from the group consisting of a Mg-containing oxide with spinel structure, MgCO 3  and MgO. 
 
     
     
       2. The raw material composition for preparing a sintered body of aluminum titanate according to  claim 1 , wherein the alkali feldspar has such a composition that x in the formula: (Na x K 1-x )AlSi 3 O 8  is in the range of (0≦x≦1) 0.1≦x≦1. 
     
     
       3. The raw material composition for preparing a sintered body of aluminum titanate according to  claim 1  or  2 , wherein the molar ratio of Si in the alkali feldspar to Mg in the Mg-containing component is in the range of Si:Mg=0.9:1 to 1.1:1. 
     
     
       4. A process for preparing a sintered body of aluminum titanate, the process comprising sintering a formed product at a temperature of 1300 to 1700° C.
 the formed product being prepared from a raw material composition for preparing a sintered body of aluminum titanate comprising:
 (i) 100 parts by weight of a mixture comprising 40 to 50 mol % of TiO 2  and 60 to 50 mol % of Al 2 O 3 , 
 (ii) 1 to 10 parts by weight of an alkali feldspar represented by the formula: (Na x K 1-x )AlSi 3 O8 (0≦x≦1), and 
 (iii) 1 to 10 parts by weight of at least one Mg-containing component selected from the group consisting of a Mg-containing oxide with spinel structure, MgCO 3  and MgO. 
 
 
     
     
       5. A sintered alloy body of aluminum titanate which is obtainable by the process comprising sintering a formed product at a temperature of 1300 to 1700° C.,
 the formed product being prepared from a raw material composition for preparing a sintered body of aluminum titanate comprising:
 (i) 100 parts by weight of a mixture comprising 40 to 50 mol % of TiO 2  and 60 top to 50 mol % Al 2 O 3 , 
 (ii) 1 to 10 parts by weight of an alkali feldspar represented by the formula:(Na x K 1-x )AlSi 3 O 8  (0≦x≦1), and 
 (iii) 1 to 10 parts by weight of at least one Mg-containing component selected from the group consisting of a Mg-containing oxide with spinel structure, MgCO 3  and MgO, and the molar ratio of Si in the alkali feldspar to Mg in the Mg-containing component being in the range of Si:Mg=0.9:1 to 1.1:1. 
 
 
     
     
       6. A sintered body of aluminum titanate comprising, calculated on an oxide basis, the following amounts of components (i) to (vi):
 (i) 100 parts by weight of aluminum titanate represented by the composition formula: Al 2 TiO 5 ;   (ii) 0.9 to 39.7 parts by weight of Al 2 O 3 ;   (iii) 0.6 to 8.7 parts by weight of SiO 2 ;   (iv) 0 to 1.5 parts by weight of Na 2 O;   (v) 0 to 2.2 parts by weight of K 2 O; and   (vi) 0.3 to 3.6 parts by weight of MgO,   wherein the amounts of Si, Na and K contained in the sintered body, calculated as SiO 2 , Na 2 O and K 2 O respectively, satisfy the following relation:
   (Na 2 O+K 2 O)/SiO 2 =0.172 to 0.261.  
   
     
     
       7. The sintered body of aluminum titanate according to claim 6 wherein Si and Mg replace mainly Al sites in aluminum titanate.