Abradable composition, a method of manufacturing an abradable composition and a gas turbine engine having an abradable seal
 An abradable seal comprises a plurality of hollow aluminosilicate spheres in a matrix of aluminium phosphate. The matrix of aluminium phosphate also has an aluminosilicate filler. The hollow aluminosilicate spheres have a diameter in the range of 400 to 1800 microns, preferably a diameter in the range of 800 to 1400 microns. The weight proportion of hollow aluminosilicate spheres in the abradable seal is 30% to 50%. The density of the abradable seal is 1.5 grammes per cubic centimetre. The hollow aluminosilicate spheres in the aluminium phosphate matrix have a relatively high temperature capability of approximately 1300.degree. C. maximum. This makes the abradable seal better able to withstand the environment in the turbine of a turbofan gas turbine engine. 
Rolls-Royce plc
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Michael J. L. Stephen Gary B. Paul A.
Percival Mason Merrill Doleman