High temperature erosion resistant coating and material containing compacted hollow geometric shapes

A material system comprising a substantially close packed array of generally contacting geometric shapes having a coordination number greater than or equal to 1 and having a 70% to 100% dense wall structure, which are bonded together, and which material system has a constrained stabilized porosity and is abradable, thermally insulating, and thermally stable at temperatures up to at least 1600° C., and where the system is disposed on a substrate.

A material system comprising an array of generally contacting spheres having a coordination number of from 5 to 12, a wall thickness greater than about 100 micrometers, which are bonded together into a three-dimensional structure, where the space between the spheres is at least partly filled with a material comprising a ceramic binder, to provide a system that is from 15 vol. % to 90 vol. % porous and thermally stable at temperatures up to at least 1600° C.