To inexpensively and securely prevent the sticking of webs after sintering by thermally spraying alumina on a substrate such as a carbon sheet and a stainless sheet to form an alumina film of a specified thickness, interposing and laminating the same on the space between plural webs to be sintered and executing sintering.

Separation materials for web sintering having an alumina film formed by thermally spraying alumina on a substrate are interposed and laminated by plural pieces on the space between webs of filters or the like, and sintering is executed. In this alumina film, thickness is controlled to ≥30 μm, preferably to 40 to 70 μm in particular, and, if required, SiO2, TiO2, ZrO2 or the like can be added thereto. Moreover, as the substrate, a carbon steel, preferably, a carbon fiber-reinforced carbon sheet, a stainless sheet, a stainless wire net or the like is used. This separation material is excellent in heat resistance and separating capacity, webs after sintering are separated without the generation of sticking and moreover capable of repeated use for many times.