Preparation method of blue mullite

Abstract

The invention discloses a preparation method of blue mullite. The preparation of the blue mullite is realized by doping metallic aluminum or an aluminum-containing compound; a secondary crystallization method is combined with an inner crucible device to control the uniformity of the doped metallic aluminum so as to obtain blue mullite with uniform color. The preparation method comprises the following steps of: firstly, fully mixing high-purity silicon carbide powder with doped metallic aluminum or aluminum-containing compound; selecting polycrystalline mullite as a seed crystal in a crystal growth furnace to grow doped polycrystalline mullite by a physical vapor transport method; taking out the polycrystalline mullite, breaking and putting the polycrystalline mullite into an inner crucible; putting high-purity silicon carbide powder into the bottom of an outer crucible; selecting monocrystal mullite as a seed crystal to be subjected to physical vapor transport growth again, so as to obtain blue mullite with uniform color. The aluminum and silicon carbide powder are combined in the first growth, the aluminum is slowly released along with the gasification of the silicon carbide in the second growth process, and therefore, the aluminum uniformly enters the mullite, and color uniformity control is achieved.

Description

technical field [0001] The invention relates to a method for preparing moissanite, in particular to a method for preparing blue moissanite. Background technique [0002] Moissanite, also known as silicon carbide gem, also known as moissanite, has been discovered for more than 100 years. Natural moissanite was first discovered in 1905. Moissanite is an inorganic compound, its chemical formula is SiC, and it is composed of silicon-carbon tetrahedrons. It has strong covalency. It has the characteristics of high melting point and high hardness. Its hardness is equivalent to that of diamonds, and it is resistant to corrosion and radiation. . Because of the high melting point, the thermal stability is very good, and the general temperature will not destroy the crystal structure of moissanite. [0003] Diamond is a well-known precious jewelry, which has a charming appearance, but natural diamonds are scarce, so they can be expensive. Artificial diamonds cannot be produced in larg...

AI Technical Summary

Problems solved by technology

However, this method for preparing colored moissanite cannot control the release rate of doping substances, so the color uniformity of the obtained moissanite crystals is poor. In the early stage of growth, more doping substances are released, so the color near the seed crystal area is relatively poor. Deep, in the later stage of growth, the doping substances are almost released and there is little left, and the color of moissanite is very light

Images