摘要
Hematite pigment has a long history,but it cannot be used for ceramic application,because it must be thermally and chemically stable at high firing temperature when using a pigment in a glaze or ceramic body.Recently,through encapsulated systems,a new pigment with suitable thermal and chemical stability can be obtained by encapsulating hematite crystals into selected silica or zircon matrices.It means that nano-sized red hematite has been encapsulated into the protected phases.Transmission electron micrographs of hematite encapsulated into silica and zircon matrices by sol-gel method show spherical single crystals with diameter of about 5-10 nm.In order to optimize ceramic glaze formulations for application of the synthesized red inorganic nanocomposite inclusion pigment by sol-gel method,four different types of glazes(i.e.,alkalis,borate,earth alkalis,and leaded glazes)have been tested.The results show that the substitution of a fraction of zircon by cristobalite in hematite-zircon pigment produces acceptable stability with red hue.
