Graded material and method for synthesis thereof and method for processing thereof

摘要

In homogeneous materials, etching characteristics depend on properties inherent in these materials regardless of whether they are isotropic or anisotropic, and there have been limitations in realizing various desired shapes. A subject for the invention is to provide a gradient material which eliminates these limitations. A gradient material is provided in which the rate of etching with a specific chemical substance changes continuously or by steps from the outermost surface to an inner part thereof. This gradient material is made of a main material which contains an additive capable of changing the etching rate of the main material so that the concentration of the additive changes continuously or by steps. Especially when a glass material containing SiO₂ as the main component is used as the main material and fluorine is used as the additive, then a gradient material in which the rate of etching with an aqueous solution of hydrofluoric acid changes in the depth direction can be obtained.