Chemical Composition for Production of Hollow Spherical Glass Particles with High Compressive Strength

Abstract

A hollow spherical glass particle, comprising aluminum oxide Al2O3, silicon dioxide SiO2 and at least one metal oxide, wherein the metal oxide is selected from the group consisting of alkali metal oxides and alkaline earth metal oxides, wherein the ratio of aluminum atoms to alkali metal atoms is about 1:1 and the ratio of aluminum atoms to earth alkali atoms is about 2:1, with the proviso that the hollow spherical glass particle is free of boron.

What is claimed is: 
     
         1 . A hollow spherical glass particle, comprising:
 aluminum oxide Al 2 O 3 , silicon dioxide SiO 2  and at least one metal oxide, wherein the metal oxide is selected from the group consisting of alkali metal oxides and alkaline earth metal oxides;   wherein the ratio of aluminum atoms to alkali metal atoms is about 1:1 and the ratio of aluminum atoms to earth alkali atoms is about 2:1;   with the proviso that the hollow spherical glass particle is free of boron.   
     
     
         2 . The hollow spherical glass particle of  claim 1 , wherein the hollow spherical glass particle comprises between about 32 wt. % and about 40 wt. %, preferably about 36 wt. %, of Al 2 O 3 , between about 38 wt. % and about 46 wt. %, preferably about 42 wt. %, of SiO 2 , and between about 18 wt. % and about 26 wt. %, preferably about 22 wt. %, of at least one alkali metal oxide. 
     
     
         3 . The hollow spherical glass particle of  claim 2 , wherein the hollow spherical glass particle comprises between about preferably 18 wt. % and about 26 wt. %, preferably about 22 wt. %, of a mixture of K 2 O and Na 2 O. 
     
     
         4 . The hollow spherical glass particle of  claim 1 , wherein the hollow spherical glass particle has a particle diameter of between about 10 and 600 microns, preferably between about 90 and 500 microns. 
     
     
         5 . The hollow spherical glass particle of  claim 4 , wherein the hollow spherical glass particle has a particle diameter of between 100 and 400 microns. 
     
     
         6 . The hollow spherical glass particle of  claim 1 , wherein the hollow spherical glass particle has an 80% crush strength of at least 10000 psi, more preferably at least 12500 psi, especially at least 15000 psi. 
     
     
         7 . The hollow spherical glass particle of  claim 1 , wherein the hollow spherical glass particle has melting temperature of at least 1200° C. 
     
     
         8 . A plurality of hollow spherical glass particles of  claim 1 . 
     
     
         9 . The plurality of hollow spherical glass particles of  claim 8 , wherein the hollow spherical glass particles have a true density of between about 0.4 g/cm 3  and 0.8 g/cm 3 , more preferably between about 0.45 g/cm 3  and 0.75 g/cm 3 , more preferably between about 0.5 g/cm 3  and 0.6 g/cm 3 . 
     
     
         10 . A filler comprising the plurality of hollow spherical glass particles of  claim 1 . 
     
     
         11 . Use of the filler of  claim 10  in metal matrix syntactic foams. 
     
     
         12 . A metal matrix syntactic foam comprising the filler of  claim 10  and a metal and/or a metal alloy. 
     
     
         13 . The metal matrix syntactic foam of  claim 12 , wherein the metal is aluminum. 
     
     
         14 . The metal matrix syntactic foam of  claim 12 , wherein the metal alloy is an aluminum alloy.