Chrysoberyl single crystal and method of producing the same

Details Chrysoberyl single crystal and method of producing the same Chrysoberyl single crystal and method of producing the same

1984-04-26

1987-01-06

Bell, Mark L.

Adhesive bonding and miscellaneous chemical manufacture

Delaminating processes adapted for specified product

Delaminating in preparation for post processing recycling step

156DIG61, 501 86, C30B 1322, C30B 2920, C30B 2922

Patent

active

046344926

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

The present invention relates to a chrysoberyl single crystal displaying a luminous band effect and a method of producing the same.


BACKGROUND ART

Growth of a chrysoberyl single crystal displaying a luminous band effect has been attempted hitherto by making a raw material bar using beryllium oxide, aluminum oxide and titanium (III) oxide, by growing a single crystal with a condense-heating floating zone method, and by carrying out further heat-treatment.
However, because the production of the raw material and the growth of a crystal are carried out in a normal atmosphere, titanium becomes quadrivalent, making it difficult to solid-dissolve it into the chrysoberyl single crystal, and making it difficult to obtain a single crystal even if it does solid-dissolve to some extent. Accordingly, the production of a chrysoberyl single crystal in which titanium is solid-dissolved has been difficult, and the resultant single crystal does not display a luminous band effect even after heat-treatment.


DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a chrysoberyl single crystal of high quality excellent in displaying a luminous band effect.
Another object of the present invention is to provide an efficient method of producing a chrysoberyl single crystal of high quality excellent in displaying a luminous band effect.
A chrysoberyl single crystal displaying a luminous band effect according to the present invention is provided by heat-treating a chrysoberyl single crystal containing solid-dissolved trivalent titanium.
The method according to the present invention to produce the above-mentioned chrysoberyl single crystal displaying a luminous band effect is characterized in that a chrysoberyl single crystal is grown by heating, by means of a condense-heating floating zone method in a non-oxidizing gas atmosphere, a raw material bar which has been made by sintering or melting and solidifying beryllium oxide and aluminum oxide of nearly equal molar amounts as principal components and a small amount of titanium (III) oxide and coloring metal oxide, by means of a condense-heating floating zone method in a non-oxidizing gas atmosphere, and then needle crystals of titanium (III) oxide are deposited in one orientation in the chrysoberyl single crystal by heat-treating said single crystal.


BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an explanatory drawing of a floating apparatus of a condense-heating type used to practice the method of the present invention .


BEST MODE FOR CARRYING OUT THE INVENTION

The term "luminous band effect" in the present invention means the effect given by needle crystals precipitated systematically in a single crystal, such as a cat's-eye and a star ruby, thereby presenting a cat's-eye or star-like appearance when exposed to a light.
In a chrysoberyl single crystal of the present invention, the principal component thereof has a composition of the formula BeAl.sub.2 O.sub.4, and iron, chromium, vanadium, and the like are solid-dissolved into said principal component in a molar amount of from 0.1 to 0.4 percent.
In order to produce a chrysoberyl single crystal displaying a luminous band effect, it is necessary to grow a single crystal in which titanium (III) is solid-dissolved, then to deposit needle crystals of titanium oxide in a definite direction in the single crystal by heat-treatment, and make a cabochon cut in that direction. The important factors in this method are the growth of a chrysoberyl single crystal in which titanium is solid-dissolved and the heat-treatment of the single crystal.
When titanium is solid-dissolved in chrysoberyl (BeAl.sub.2 O.sub.4), titanium is substituted for trivalent aluminum ion and solid-dissolved. In this case, the substituted titanium ion must be trivalent, in order to maintain an electrical neutrality.
In the present invention, the above-mentioned problem has been solved by regulating the valency of titanium to trivalent using a non-oxidizing atmosphere in the stages of making a raw material bar and growing a si

REFERENCES:
patent: 4218282 (1980-08-01), Kochi

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