Interference No. 103,995 Paper 29
Morel v. Sekhar Page 23
These silicon-based combinations can be used alone or in
combination with other silicon or non-silicon non-reactants or with
micropyretic reactants, and particularly with colloidal silica in the carrier.
When such coatings are sintered before use in an oxidsing [sic, oxidizing]
atmosphere, or when such coatings are used in an oxidizing atmosphere,
the coatings are converted to produce a relatively impervious silica skin.
[SDEx 3, c. 7, ll. 1-8.]
Sekhar points to WO 88/03519 (MDEx 1), p. 5, ll. 1-14 to show that “skin” and
“glass” are equivalent terms.
45. WO 88/03159 describes
The titanium diboride provides a source in the mixture for boron to be
supplied into the silicates to form varying degrees of boro-silicate glasses.
The titanium oxidizes to varying degrees to generate nucleation points for
crystal growth in the boro-silicate glasses. It is believed that the titanium
enters into the silicate mass as part of a crystal structure. Introducing these
boron and titanium components into the silicates in this manner evidently
causes high temperature glass to form in situ and generate a hermetic skin
supported first by the powder silicate mass. The composition of this healing
skin or layer alters with temperature and time. The diffusing atmosphere
causes this reaction to proceed to thicken the skin and increase its thermal
resistance. [MDEx 1, p. 5, ll. 1-14.]
46. Morel also uses an oxidizing atmosphere, see e.g.,
The coating according to the [Morel] invention vitrifies between 600
o
and 700 C. To obtain efficient protection, vitrification must be rapid. If the
coated component must itself be raised to a high temperature very quickly
o
(>300 /h), the coating will be vitrified under good conditions during actual
use of the component. If on the other hand the coated component has to
undergo a slow rise in temperature, vitrification pretreatment will be
[4]
necessary, advantageously by using a blowpipe. This method of heat-
treatment results in a deposit of non-uniform thickness. Glass forms only at
4Hackh’s CHEMICAL DICTIONARY, fourth edition, (McGraw-Hill Book Company, New York,
published 1969) defines a blowpipe as “A metal tube tapering to a fine point, used to blow air into a flame
and to direct it as a fine conical tongue in qualitative or mineralogical analysis, soldering, melting in
dentistry or jewelry manufacture” at page 103.
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