US PATENT SUBCLASS 501 / 2
.~ Devitrified glass-ceramics

Current as of: June, 1999
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501 /   HD   COMPOSITIONS: CERAMIC

1  DF  CERAMIC COMPOSITIONS {15}
2.~ Devitrified glass-ceramics {4}
3  DF  .~.~> Halogen containing crystalline phase (e.g., fluormica, etc.)
4  DF  .~.~> Silica containing crystalline phase (e.g., stuffed quartz, crystobalite, etc.)
5  DF  .~.~> Binary, ternary, quaternary, etc., metal silicate crystalline phase (e.g., mullite, diopside, sphene, plagioclase, slagcerams free of alumina, etc.) {2}
10  DF  .~.~> Nonsilica and nonsilicate crystalline phase (e.g., spinel, barium titanate, etc.)

DEFINITION

Classification: 501/2

Devitrified glass ceramics:

(under subclass 1) Compositions containing a crystalline phase embedded in a glassy (amorphous) phase, which crystalline phase is produced by cooling a molten glass composition to a temperature which causes a portion only of the composition to crystallize while the remainder of the composition (the matrix) solidifies in the amorphous or glassy state.

(1) Note. The crystalline phase is typically uniformly dispersed throughout the glassy phase and it must constitute

at least 50 percent by weight of the total composition.

(2) Note. The subclasses indented hereunder are established on the basis of the nature of the crystalline phase. Patents placed as originals in the indented subclasses may be cross-referenced when appropriate in other subclasses of this class on the basis of the nature of the glassy matrix phase.

(3) Note. Documents classified as originals in this and indented subclasses are cross-referenced on the basis of the chemical nature of the glass composition disclosed into subclasses 40, 41+, and/or 53+, as appropriate.

(4) Note. Documents classified as originals in this and indented subclass which are directed to optical glass compositions are cross-referenced to subclasses 900+.