chrome inlay in a saturated iron glaze
This is a further exploration of a firing which has a slow up-fire in
addition to having the usual
The matrix glaze, oribe-satIron-Z4L-0, is a high silica, saturated
iron-phosphorus glaze.
The inlay glaze, caAlSi_PSi_Cr, is close to the calcium-alumina-silica
eutectic, (see Bergeron, Rissbud,
It would appear as if the background glaze, in the process of flowing through
the inlay, ate the
Using a Jiusion digital microscope, I have verified that the white markings
are crystals.
The matrix (i.e., background) glaze and inlay glaze overlap minimally before
firing. The width of the
The design is created by adhering a mask and then applying the main
glaze. After drying,
The close-up images were heavily edited to enhance detail. The colors of the
full image of the bowl
400 deg F an hour to 1800 deg F
300 deg F an hour to 2050 deg F
200 deg F an hour to 2220 deg F then a 90 min hold at 2220 deg F
90 deg F an hour to 2320 deg F
300 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
25 deg F an hour to 1650 deg F then a 1 hr hold at 1650 deg F
K2O 0.15
Al2O3 0.54
SiO2 3.47
molecular percent Silica 65.7%
Added:
5% cobalt carbonate
K2O 0.005
Al2O3 0.41
SiO2 2.86
molecular percent Silica 63.8%
Added:
0.4% Chrome Oxide
This firing features a 'rounded at the top' firing profile; with a hold of an
hour and a half at 100 degreesF
holds on the way down.
"Phase Equilibria in Ceramics", The
American Ceramic Society) with added silica, titanium, tin
and chrome.
It is a micro-crystalline matte glaze, and the inlay itself has
stayed very close to the
original position of the masks which defined the
design.
glassy substrate of the inlay glaze, leaving behind the
surface micro-crystals.
original inlay varied from an eighth of
an inch to three quarters 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.
are as they appear in bright light.
Close up Images of the interaction region
Image of the piece
bowl with glaze oribe-satIron-Z4L-0 and inlay caAlSi_PSi_Cr
bowl is ~6 inches in diameter
oxidation firing to a hot cone 10 in an electric kiln
Firing profiles
Up Fire profile hot cone 10
Down Fire Profile hot cone 10
Clay body is a grolleg porcelain from Clay Art Center in Tacoma, WA.
glaze composition
Empirical Formula oribe-satIron-Z4L-0 :
Na2O 0.30
CaO 0.42
MgO 0.13
Fe2O3 0.22
P2O5 0.05
Inlay Glaze:
Empirical Formula caAlSi_PSi_Cr
Na2O 0.005
CaO 0.98
MgO 0.01
TiO2 0.13
SnO2 0.07
Remarks
below top temperature, and a slow climb
from there to the top temperature.