Folowup on Chrome Oxide in a strontium/rutile glaze
cone 10 oxidation
Firing profile
A two hour hold at 1850 deg F
A half hour hold at 1750 deg F
A three hour hold at 1700 deg F
slow downfire at 25 deg F an hour in the interval 1700 deg F to 1650 deg F
A half hour hold at 1650 deg F
I have no reason to think this firing profile is necessary to this glaze
There were other glazes in this test firing to which it was relevant.
Clay body is a grolleg porcelain from Tacoma Clay Art Center.
glaze composition
In the empirical Formula:
The glaze has nearly equal alkali metals and alumina at 0.5 and silica 3
The remaining non alkali metal bases are
MgO is .29
SrO is .16
CaO is .05
TiO2 is .17
This glaze, paperWhite_ZI_0 contains substantial TiO2, and Strontium and is
yellow with Chrome oxide.
Here are two variants of that glaze, one
suggested by Pete Pinnell has no Li2O (and named by him
carolKnightenYellow).
The other suggested by Fara Shimbo which has K2O
substituted for most of the Na2O.
likely both of these glazes have a bit less Chrome Oxide that the first glaze.
It would seem there is some wiggle room on the balance of the alkali metals to get the yellow color.
The pots are small distorted cones ~4 inches in diameter.
paperWhite_ZI_0 0.1 % Chrome oxide
glaze carolKnightenYellow + .1 % chrome oxide
glaze chrome_2017-08-0 + .1 % chrome oxide