Method for producing aluminum magnesium titanate sintered product

Abstract

The present invention provides a process for preparing a sintered body comprising as a basic component aluminum magnesium titanate represented by the composition formula: Mg x Al 2(1−x) Ti (1+x) O 5 wherein the value of x is 0.1≦x<1. The process comprises a step of sintering a formed product from a raw material mixture comprising 100 parts by weight, calculated on an oxide basis, of a mixture comprising a Mg-containing compound, an Al-containing compound and a Ti-containing compound at the same metal component ratio as the metal component ratio of Mg, Al and Ti in the above composition formula, and 1–10 parts by weight of an alkali feldspar represented by the composition formula: (Na y K 1−y )AlSi 3 O 8 wherein the value of y is 0≦y≦1. According to the process of the present invention, a sintered body of aluminum magnesium titanate having stability in continuous use at high temperatures and excellent mechanical strength, while maintaining inherently low thermal expansibility of a sintered body of aluminum magnesium titanate, can be obtained.

1. A process for producing a sintered body comprising as a basic component aluminum magnesium titanate represented by the composition formula:
   Mg x Al 2(1−x) Ti (1+x) O 5    
 
       wherein the value of x is 0.1≦x<1,
 the process comprising a step of sintering a formed product from a raw material mixture comprising the ingredients (i) and (ii) below: 
 (i) 100 parts by weight, calculated on an oxide basis, of a mixture comprising a Mg-containing compound, an Al-containing compound and a Ti-containing compound at the same metal component ratio as the metal component ratio of Mg, Al and Ti in the composition formula, 
 (ii) 1–10 parts by weight of an alkali feldspar represented by the composition formula:
   (Na y K 1−y )AlSi 3 O 8    
 
 
       wherein the value of y is 0≦y≦1. 
     
     
       2. A process of producing a sintered body of aluminum magnesium titanate according to  claim 1 , wherein the value of x in the composition formula: Mg x Al 2(1−x) Ti (1+x) O 5  is 0.25≦x≦0.75. 
     
     
       3. A process of producing a sintered body of aluminum magnesium titanate according to  claim 1 , wherein the value of y in the composition formula: (Na y K 1−y )AlSi 3 O 8  is 0.15≦y≦0.85. 
     
     
       4. A process of producing a sintered body of aluminum magnesium titanate according to  claim 1 , wherein a sintering temperature is 1000–1700° C. 
     
     
       5. A sintered body of aluminum magnesium titanate which is obtainable by the process of  claim 1 . 
     
     
       6. A sintered body of aluminum magnesium titanate comprising, calculated on an oxide basis, the following amounts of components (i) to (v):
 (i) 100 parts by weight of aluminum magnesium titanate represented by the composition formula: Mg x Al 2(1−x) Ti (1+x) O 5  wherein the value of x is 0.1≦x<1,   (ii) 0.18 to 1.95 parts by weight of Al 2 O 3 ;   (iii) 0.65 to 6.87 parts by weight of SiO 2 ;   (iv) 0 to 1.18 parts by weight of Na 2 O; and   (v) 0 to 1.69 parts by weight of K 2 O, and   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 magnesium titanate according to claim 6 wherein Si dissolves into the crystal system of aluminum titanate and occupies mainly Al site.  
     
     
       8. The sintered body of aluminum magnesium titanate according to claim 6 wherein a pair of Si and Mg replaces neighboring two Al atoms.