Glaze Reactions in an iron glaze with a chrome bearing inlay
Here is a mug with a red inlay design with a lacy grey-green edge.
The iron background glaze, satIron_ZG_Z3N_Z3T, contains two distinct
micro-crystalline inclusion
The interaction between these two glazes produced a new grey-green phase.
This phase contains little
The flow patterns seen in the close-up images of the inlay glaze suggest that
it exhibits liquid-liquid
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 editied to enhance detail, colors are
brighter as a result.
150 deg F an hour to 250 deg F
300 deg F an hour to 1800 deg F
200 deg F an hour to 2050 deg F
120 deg F an hour to 2320 deg F with a hold of 25 minutes at 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 0.12
Al2O3 0.75
SiO2 3.51
molecular percent Silica %
K2O 0.11
Al2O3 0.35
SiO2 2.90
molecular percent Silica 65.01%
Added:
0.4% Chrome Oxide
Chrome migrates from high concentration in the inlay glaze, to low
concentration
Components can also migrate by fluid flow while the glaze is molten. Both
matrix glaze and inlay
as well as metallic coppery colored
micro-crystals, and silvery gunmetal spots. These gunmetal
spots are
most distinctly seen in the third close-up image. The inlay design glaze
oribe-woof-PAl-Cr
is a glossy chrome red.
iron, as shown by its light color. The pale
green tint shows that it contains some chrome. If neither
the rutile nor Tin
made it into this phase, that would explain its loss of the red tint.
Alternatively,
might it be high in alumina? Its composition is
substantially different from either
the inlay glaze or the matrix glaze.
phase separation. The distinct phases in both
matrix glaze and inlay glaze account for the complex
movement within
the two glazes, and the distribution of the bits of the new phase formed.
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.
The colors in the full image of the mug are
accurate.
Close up Images of the interaction region
Image of the piece
mug with glaze satIron_ZG_Z3N_Z3T and inlay glaze oribe-woof-PAl-Cr
mug is ~4 inches high
oxidation firing to cone 10 in an electric kiln
Firing profiles
Up Fire profile hot cone 10
Down Fire Profile cone 11
Clay body is a grolleg porcelain from Clay Art Center in Tacoma, WA.
glaze composition
Empirical Formula satIron_ZG_Z3N_Z3T :
Na2O 0.53
CaO 0.28
MgO 0.07
Fe2O3 0.23
P2O5 0.07
Inlay Glazes:
Empirical Formula oribe-woof-PAl-Cr:
Na2O 0.03
CaO 0.85
MgO 0.01
TiO2 0.13
SnO2 0.07
Remarks
in the matrix glaze. Iron and phosphorus migrate in the
opposite direction from the matrix glaze into the
inlay glaze.
glaze have multiple liquid phases.