Modification of alkaline earth silicate fibres

Abstract

A method of making refractory alkaline earth silicate fibres from a melt, including the use as an intended component of alkali metal to improve the mechanical properties of the fibre in comparison with a fibre free of alkali metal.

1 . A method of making refractory alkaline earth silicate fibres comprising less than 10 wt % alumina from a melt, comprising the inclusion as an intended melt component of alkali meta to improve the mechanical and/or thermal properties of the fibre. 
     
     
         2 - 25 . (canceled) 
     
     
         26 . Alkaline earth silicate fibres having a composition comprising >15% by weight MgO and comprising as an additive alkali metal (M) comprising predominantly lithium in the amount expressed as the oxide M 2 O 0.2 mol % to 2.5 mol %. 
     
     
         27 . Fibres, as claimed in  claim 26 , in which M 2 O is present in an amount 0.25 mol % to 2.5 mol %. 
     
     
         28 . Fibres, as claimed in  claim 26 , in which M 2 O is present in an amount greater than or equal to 0.3 mol % to 2 mol %. 
     
     
         29 . Fibres, as claimed in  claim 26 , in which M 2 O is present in an amount greater than or equal to 0.4 mol % to less than 1.5 mol %. 
     
     
         30 . Fibres, as claimed in  claim 26 , in which M 2 O is present in an amount greater than or equal to 0.5 mol % to less than 1 mol %. 
     
     
         31 . Fibres, as claimed in  claim 30 , in which M 2 O is present in an amount less than 0.75 mol %. 
     
     
         32 . Alkaline earth silicate fibres having a composition comprising in relative weight percent:—
 SiO 2  6-86% 
 MgO>15-35% 
 
       the components MgO and SiO2 comprising at least 82.5% by weight of the fibre, and comprising as an additive alkali metal (M) comprising predominantly lithium in the amount expressed as the oxide M 2 O 0.2 mol % to 2.5 mol %. 
     
     
         33 . Fibres, as claimed in  claim 32 , in which M 2 O is present in an amount 0.25 moil % to 2.5 mol %. 
     
     
         34 . Fibres, as claimed in  claim 33 , in which M 2 O is present in an amount greater than or equal to 0.3 mol % to 2 mol %. 
     
     
         35 . Fibres, as claimed in  claim 34 , in which M 2 O is present in an amount greater than or equal to 0.4 mol % to less than 1.5 mmol %. 
     
     
         36 . Fibres, as claimed in  claim 35 , in which M 2 O is present in an amount greater than or equal to 0.5 mol % to less than 1 mol %. 
     
     
         37 . Fibres, as claimed in  claim 36 , in which M 2 O is present in an amount less than 0.75 mol %.