Strain tolerant porous silicon nitride

An approach to material strain tolerance, which basically makes it possible to lower the elastic modulus while retaining strength, was experimentally confirmed using as an example a porous silicon nitride composed of oriented anisotropic grains and pores. The porous structure consisting of tightly tangle rodlike grains and anisotropic pores was obtained by using {beta}-Si{sub 3}N{sub 4} whiskers. This material exhibited a low Young`s modulus while retaining a relatively high fracture stress, even though it contained 14.4% porosity. Consequently, the strain to failure of silicon nitride was appreciably increased.