Phosphorus

I show two high phosphorus glazes.

These glazes show a layer of apparently metallic crystals with a glossy iron colored layer below.

For each glaze I show closeup images of the glaze. for reference an image of the pot with the second glaze is shown.

An image of the first glaze on a pot is not available.

cone 10 oxidation

Firing profile

Up Fire profile

150 deg F an hour to 250 deg F
400 deg F an hour to 1800 deg F
300 deg F an hour to 2050 deg F
120 deg F an hour to 2310 deg F with a hold of 20 minutes at 2310 deg F

Down Fire Profile

A one hour hold at 1750 deg F
A three hour hold at 1700 deg F
A two hour hold at 1650 deg F

The cones show this as a hot cone 10 firing.

Clay body is a grolleg porcelain from Tacoma Clay Art Center.

glaze compositions

Empirical Formula glaze satIronZT_mashikoCNeph :

K2O        .08
Na2O        .01
Li2O        .25
CaO        .44
MgO        .22

Al2O3        .6
Fe2O3        .23

SiO2        4.12
P2O5        .15

molecular percent Silica 67%

Empirical Formula glaze satIron_ZT_mashikoLi_1H :

K2O        .01
Na2O        .01
Li2O        .23
CaO        .45
MgO        .31

Al2O3        .55
Fe2O3        .22

SiO2        3.67
P2O5        .15

molecular percent Silica 66%

glaze satIronZT_MashikoCNeph

closeups of tile

tile is ~ 4 inches x 3 inches

glaze satIron_ZT_MashikoLi_1H

closeup

pot

bowl ~ 4 inches in diameter

Remarks

The first glaze satIronZT_MashikoCNeph has a lumpy surface and is underfired, yet has a larger metallic crystals,
and higher contrast between crystals and background.

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