Glaze Reactions
A high titanium matrix glaze with a high silica inlay glaze containing copper is
seen here:
In this note, the matrix glaze is oribe-woof-PAlZr, which is a copper bearing
glaze, the inlay
This firing is an "invert" firing, dropping first to 1650 degF, then climbing
back to 1850 degF;
The inlay glaze, on its own, has a translucent white ground with scattered
white micro-crystalline
Here we see a spiral, the inlay stained olive, framed by the interaction
region in rings moving
Diffusion of copper into the inlay glaze stains it olive; absorption of the
copper into the
The titanium crystals that grow after the diffusion of copper has terminated are
white. The growth of
As the matrix glaze is adjacent to the white titanium crystals, these white
crystals grew at a time
The matrix (i.e., background) glaze and inlay glaze overlap minimally before
firing. The width of the
The background glaze is oribe-woof-PAlZr; the inlay design is glazed with
hiAlk_Z3P_Z3V_0
The design is created by adhering a mask and then applying the main
glaze. After drying,
150 deg F an hour to 250 deg F
300 deg F an hour to 2050 deg F
120 deg F an hour to 2330 deg F with a hold of 30 minutes at 2330 deg F
300 deg F an hour to 1650 deg F then a 3 hr hold at 1650 deg F
400 deg F an hour to 1850 deg F then a 2 hr hold at 1850 deg F
300 deg F an hour to 1750 deg F then a 1 hr hold at 1750 deg F
300 deg F an hour to 1700 deg F then a 3 hr hold at 1700 deg F
K2O 0.10
Al2O3 0.41
SiO2 2.97
molecular percent Silica 66%
Added:
5.0% Copper Oxide
K2O 0.18
Al2O3 0.64
SiO2 3.54
molecular percent Silica 64.9%
The glaze interactions in the boundary between matrix glaze and inlay glaze
are dominated by kinetic
Silica migrates from high concentration in the inlay glaze,
to low concentration
is decorated with hiAlk_Z3P_Z3V_0, a high alkali metal
titanium glaze. This reverses the character
of the matrix and inlay
glazes seen in the above note.
additionally, this firing is to cone 11.
clusters.
outward, the closest in is tan, then white.
micro-crystalline titanium clusters creates shades of brown
and tan.
white crystals surrounding the brown crystals shows
that titanium crystals have grown after copper
diffusion has ended.
when copper was no longer diffusing. This
suggests that titanium crystals can grow at a lower
temperature than that
at which copper readily diffuses into the inlay glaze
original inlay varied from an eighth of an inch to
three eighths of an inch.
the mask is removed and the open area filled in with a
second glaze, using a bulb syringe
with a needle applicator.
Close up Images of the interaction region
Image of the piece
bowl with glaze oribe-woof-PAlZr and inlay glaze hiAlk_Z3P_Z3V_0
bowl is ~10 inches in diameter
oxidation firing to cone 11 in an electric kiln
Firing profiles
Up Fire profile cone 11
Down Fire Profile cone 11
Clay body is a white stoneware from Clay Art Center in Tacoma, WA.
glaze composition
Empirical Formula oribe-woof-PAlZr :
Na2O 0.03
CaO 0.71
MgO 0.16
P2O5 0.01
ZrO2 0.11
Inlay Glazes:
Empirical Formula hiAlk_Z3P_Z3V_0:
Na2O 0.41
CaO 0.31
MgO 0.10
P2O5 0.07
TiO2 0.21
Remarks
effects, i.e., these reactions can take place only
as a result of movement of oxides between the matrix
glaze and the inlay
glaze. The various oxides move at different rates, depending on temperature.
in the matrix glaze. Copper migrates in the
opposite direction from the matrix glaze into the
inlay glaze.