Zirconia stabilised with Yttria has similar properties to those of Zirconia stabilised with Magnesia, although it is harder and tougher. It also has a finer grain structure. The non-woven fabrics are felts fabricated by mechanically locking fibres and firing at a high temperature. The fabrics are flexible and chemically unreactive, being especially stable to hot caustic. It is suitable for applications such as high energy battery separators, thermal insulation in crystal growing furnaces, and for the filtration of hot gasses. It requires neither binders nor supporting wires in its construction and will comply somewhat to both tensile and compressive forces due to the mechanical interlocking of fibres. Elongation of 4 to 8% before breaking allows to ZYK-15 to conform to irregular sizes. Zirconia felt is a mechanically interlocked textile manufactured from 4-6-micron diameter fibres. It is designed for use in extremely corrosive environments and high temperatures, useful in strong oxidizing and reducing environments, unreactive to alkali vapours, salts or strong hot solutions, and non-wetting to most molten metals.