iandol on sun 16 dec 01
Dear SAM YANCY,
I take it all of your temperatures are Deg F.
Well, I must say, that beats plunging red hot steel into molten sodium =
cyanide to get carburisation. Sounds a lot more promising and much =
safer.
The two processes are as different as making beer and making bread, that =
is Carburising Steel and making Reduction Glazes. The only similarity is =
that both use the same compound to initiate the result.
In the first the idea is to get free carbon to diffuse into the surface =
of the metal to create Iron Carbide, which like many other carbides, is =
impressively hard and durable. This takes place in a solid solution =
where Iron acts as a solvent for carbon. When quenching happens the iron =
carbide crystals grow and act as a hard surface layer.
In reduction glazing, we are already using carbon rich fuels to create =
our high temperatures. To get our copper reds either the rate of feeding =
fuel is increased or the supply of air is restricted to give an =
atmosphere rich in Carbon Monoxide which will diffuse into the glaze and =
react chemically with metallic salts which we put in to get the colour.
So, no, we would not want to get free carbon which gives the carburising =
atmosphere. We already have carbon which we need to convert into a gas.
On the other hand, It might be a good idea for the Shino Aficionados who =
want to get excessive carbon trap in their surfaces.
Best regards,
Ivor Lewis. Redhill, South Australia.
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