Tom Buck on tue 25 feb 03
P.Southwood:
Silicon Carbide is technically an "alloy" not a compound in the usual
sense, ie, exchange or co-ordination of outer-shell electrons. so the
carbon is really graphite (groupings of carbon atoms) uniformly mixed with
groupings of silicon atoms.
carbon will seek oxygen atoms from other ingredients close by. if
it combines with oxygen to form carbon monoxide gas this gas will continue
the reducing activity started by the carbon atoms, and black copper oxide
will be changed to red copper oxide and copper metal.
the reduction activity needs to carried out at the smallest
possible scale to be effective. if the SiC particles/granules are too
large too much gas is evolved at one site and craters result in the glaze
rather than a change in colour.
to be an effective reducing agent, SiC should be as fine a mesh
as possible, 1000 mesh, similar to jeweler's rouge (iron oxide powder).
Such fine mesh is produced for tool/die makers who use it to polish their
metal shapes.
good pots. peace. Tom B.
Tom Buck ) -- primary address.
"alias" or secondary address.
tel: 905-389-2339 (westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street, Hamilton ON L8T 3E1 Canada
Bill Aycock, W4BSG on fri 28 feb 03
Tom was mostly right, but not about the condition of Silicon Carbide as a
mixture or "allow, not a compound. The Handbook of Chemistry and Physics
lists it as a compound, and gives a "heat of formation" for it, and that is
good enough for most people.
Besides, logic alone will help in this definition. A mixture, or Alloy can
occur in almost any proportion of one of the constituents to the other(s),
but Silicon Carbide ALWAYS comes in a one-to-one count of atom-to-atom, ie,
SiC.
The concept of "shared electrons" as a requirement for chemical compounds
was shot down when several "noble gas" compounds were created.
He also seemed to almost ignore the contribution of Silicon to the Oxygen
grab that takes place in the participation of SiC in glaze reduction. The
Silicon grabs Oxygen from any of several glaze materials to form more
Silica (SiO2) a normal glaze ingredient, when the Carbon takes up Oxygen to
make the CO2.
Bill, sitting out a very soggy Friday on Persimmon Hill.
At 03:28 PM 2/25/2003 -0500, you wrote:
>P.Southwood:
>
>Silicon Carbide is technically an "alloy" not a compound in the usual
>sense, ie, exchange or co-ordination of outer-shell electrons. so the
>carbon is really graphite (groupings of carbon atoms) uniformly mixed with
>groupings of silicon atoms.
> good pots. peace. Tom B.
Bill Aycock - W4BSG
Woodville, Alabama
Tom Buck on sat 1 mar 03
Hey Bill A!
good to hear from you; it's been awhile. Yes, my Handbook also
lists SiC as a chemical with a specific mole weight, SiC.
Please, Bill, give me an idea of how is SiC made, from what forms
of Silicon and Carbon, at what temperature, in what state (solid, liquid,
gas?). I would expect that to get a 50/50 compound, the two components
would have to be molten, or a silicon compound liquid at reasonable
temperatures would react with a form of carbon to produce the solid
crystals of SiC. My chem dictionary says SiC is made by heating carbon
and silicA in an electric furnace to a moderate temperature, whereas
2200 oC/4000 oF seems more likely.
and yes, Bill, there is some activity on the part of Silicon to
bring about reduction of glaze components, but this wouldn't cause
the cratering effect posed by the original query, only the formation of
Carbon Monoxide gas would do that. besides, solid/solid chemical reactions
are difficult to achieve and even then quite slow. Mobile gas molecules
would achieve a greater effect.
anyway, I am pleased you have posted to Clayart again.
be well. peace. Tom.
Tom Buck ) -- primary address.
"alias" or secondary address.
tel: 905-389-2339 (westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street, Hamilton ON L8T 3E1 Canada
On Fri, 28 Feb 2003, Bill Aycock, W4BSG wrote:
> Tom was mostly right, but not about the condition of Silicon Carbide as a
> mixture or "allow, not a compound. The Handbook of Chemistry and Physics
> lists it as a compound, and gives a "heat of formation" for it, and that is
> good enough for most people.
> Besides, logic alone will help in this definition. A mixture, or Alloy can
> occur in almost any proportion of one of the constituents to the other(s),
> but Silicon Carbide ALWAYS comes in a one-to-one count of atom-to-atom, ie,
> SiC.
> The concept of "shared electrons" as a requirement for chemical compounds
> was shot down when several "noble gas" compounds were created.
> He also seemed to almost ignore the contribution of Silicon to the Oxygen
> grab that takes place in the participation of SiC in glaze reduction. The
> Silicon grabs Oxygen from any of several glaze materials to form more
> Silica (SiO2) a normal glaze ingredient, when the Carbon takes up Oxygen to
> make the CO2.
> Bill, sitting out a very soggy Friday on Persimmon Hill.
>
>
> At 03:28 PM 2/25/2003 -0500, you wrote:
> >P.Southwood:
> >
> >Silicon Carbide is technically an "alloy" not a compound in the usual
> >sense, ie, exchange or co-ordination of outer-shell electrons. so the
> >carbon is really graphite (groupings of carbon atoms) uniformly mixed with
> >groupings of silicon atoms.
> > good pots. peace. Tom B.
>
> Bill Aycock - W4BSG
> Woodville, Alabama
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
>
Bill Aycock, W4BSG on sat 1 mar 03
>Tom-
Silicon Carbide, aka Carborundum, was invented by a former employee of
Edison,(named Atcheson) and has been rated as one of the most important
materials of this century.(by the Patent office) It is usually made by
immersing Carbon in molten Silicon. The use of the Silicon in liquid form
allows intimate contact. The resulting Carbide is usually pressed into
shape and then sintered at very high temperature .
To get more information, I'll have to do some REAL research.
Bill
Bill Aycock - W4BSG
Woodville, Alabama
Edouard Bastarache on sat 1 mar 03
Hello Tom,
until recently some carborandum was produced in Shawinigan, Quebec,
an industrial region you certainly know of. From what I learned from workers
the temperature used was 4,000 F.
Later,
"Ils sont fous ces Quebecois"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
http://sorel-tracy.qc.ca/~edouardb/
http://perso.wanadoo.fr/smart2000/index.htm
----- Original Message -----
From: Tom Buck
To:
Sent: Saturday, March 01, 2003 12:43 AM
Subject: Re: silicon carbide reduction
> Hey Bill A!
> good to hear from you; it's been awhile. Yes, my Handbook also
> lists SiC as a chemical with a specific mole weight, SiC.
> Please, Bill, give me an idea of how is SiC made, from what forms
> of Silicon and Carbon, at what temperature, in what state (solid, liquid,
> gas?). I would expect that to get a 50/50 compound, the two components
> would have to be molten, or a silicon compound liquid at reasonable
> temperatures would react with a form of carbon to produce the solid
> crystals of SiC. My chem dictionary says SiC is made by heating carbon
> and silicA in an electric furnace to a moderate temperature, whereas
> 2200 oC/4000 oF seems more likely.
> and yes, Bill, there is some activity on the part of Silicon to
> bring about reduction of glaze components, but this wouldn't cause
> the cratering effect posed by the original query, only the formation of
> Carbon Monoxide gas would do that. besides, solid/solid chemical reactions
> are difficult to achieve and even then quite slow. Mobile gas molecules
> would achieve a greater effect.
> anyway, I am pleased you have posted to Clayart again.
> be well. peace. Tom.
>
> Tom Buck ) -- primary address.
> "alias" or secondary address.
> tel: 905-389-2339 (westend Lake Ontario, province of Ontario, Canada).
> mailing address: 373 East 43rd Street, Hamilton ON L8T 3E1 Canada
>
> On Fri, 28 Feb 2003, Bill Aycock, W4BSG wrote:
>
> > Tom was mostly right, but not about the condition of Silicon Carbide as
a
> > mixture or "allow, not a compound. The Handbook of Chemistry and Physics
> > lists it as a compound, and gives a "heat of formation" for it, and that
is
> > good enough for most people.
> > Besides, logic alone will help in this definition. A mixture, or Alloy
can
> > occur in almost any proportion of one of the constituents to the
other(s),
> > but Silicon Carbide ALWAYS comes in a one-to-one count of atom-to-atom,
ie,
> > SiC.
> > The concept of "shared electrons" as a requirement for chemical
compounds
> > was shot down when several "noble gas" compounds were created.
> > He also seemed to almost ignore the contribution of Silicon to the
Oxygen
> > grab that takes place in the participation of SiC in glaze reduction.
The
> > Silicon grabs Oxygen from any of several glaze materials to form more
> > Silica (SiO2) a normal glaze ingredient, when the Carbon takes up Oxygen
to
> > make the CO2.
> > Bill, sitting out a very soggy Friday on Persimmon Hill.
> >
> >
> > At 03:28 PM 2/25/2003 -0500, you wrote:
> > >P.Southwood:
> > >
> > >Silicon Carbide is technically an "alloy" not a compound in the usual
> > >sense, ie, exchange or co-ordination of outer-shell electrons. so the
> > >carbon is really graphite (groupings of carbon atoms) uniformly mixed
with
> > >groupings of silicon atoms.
> > > good pots. peace. Tom B.
> >
> > Bill Aycock - W4BSG
> > Woodville, Alabama
> >
> >
____________________________________________________________________________
__
> > Send postings to clayart@lsv.ceramics.org
> >
> > You may look at the archives for the list or change your subscription
> > settings from http://www.ceramics.org/clayart/
> >
> > Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
> >
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Jim Tabor on sun 2 mar 03
Edouard, Bill, and Tom-
In 1990 or 91, I was fortunate enough to attend an Acer's annual meeting
and spent most of my time wandering the isles of exhibits in amazement.
A company from the UK had silicon carbide crystals they grew to grind
into powder and make the glowbar elements used in very high temp kilns.
The crystal chunks of silicon carbide were around 6 inches in all
directions and looked like carnival glass jewels. As I recall, they were
created at temperatures maintained for weeks at a time at well over
3000F. Crystals grew from a seed to begin formation of the structure
from the kiln's atmosphere of injected elements and not from a batch
melted into a new mass and crystallized. If I can find the literature
from the company, or an old issue of Ceramic Industry, I'll pass on the
fascinating facts. I don't recall ever seeing info on any process at
4000F. I also haven't seen anything else on sintered ceramics from
microwaves that was being demonstrated then.
Jim Tabor
Edouard Bastarache wrote:
>Hello Tom,
>
>until recently some carborandum was produced in Shawinigan, Quebec,
>an industrial region you certainly know of. From what I learned from workers
>the temperature used was 4,000 F.
>
>
>Later,
>
>
>
>
>"Ils sont fous ces Quebecois"
>Edouard Bastarache
>Irreductible Quebecois
>Indomitable Quebeker
>Sorel-Tracy
>Quebec
>edouardb@sorel-tracy.qc.ca
>http://sorel-tracy.qc.ca/~edouardb/
>http://perso.wanadoo.fr/smart2000/index.htm
>
>----- Original Message -----
>From: Tom Buck
>To:
>Sent: Saturday, March 01, 2003 12:43 AM
>Subject: Re: silicon carbide reduction
>
>
>
>
>>Hey Bill A!
>> good to hear from you; it's been awhile. Yes, my Handbook also
>>lists SiC as a chemical with a specific mole weight, SiC.
>> Please, Bill, give me an idea of how is SiC made, from what forms
>>of Silicon and Carbon, at what temperature, in what state (solid, liquid,
>>gas?). I would expect that to get a 50/50 compound, the two components
>>would have to be molten, or a silicon compound liquid at reasonable
>>temperatures would react with a form of carbon to produce the solid
>>crystals of SiC. My chem dictionary says SiC is made by heating carbon
>>and silicA in an electric furnace to a moderate temperature, whereas
>>2200 oC/4000 oF seems more likely.
>> and yes, Bill, there is some activity on the part of Silicon to
>>bring about reduction of glaze components, but this wouldn't cause
>>the cratering effect posed by the original query, only the formation of
>>Carbon Monoxide gas would do that. besides, solid/solid chemical reactions
>>are difficult to achieve and even then quite slow. Mobile gas molecules
>>would achieve a greater effect.
>> anyway, I am pleased you have posted to Clayart again.
>>be well. peace. Tom.
>>
>>Tom Buck ) -- primary address.
>>"alias" or secondary address.
>> tel: 905-389-2339 (westend Lake Ontario, province of Ontario, Canada).
>>mailing address: 373 East 43rd Street, Hamilton ON L8T 3E1 Canada
>>
>>On Fri, 28 Feb 2003, Bill Aycock, W4BSG wrote:
>>
>>
>>
>>>Tom was mostly right, but not about the condition of Silicon Carbide as
>>>
>>>
>a
>
>
>>>mixture or "allow, not a compound. The Handbook of Chemistry and Physics
>>>lists it as a compound, and gives a "heat of formation" for it, and that
>>>
>>>
>is
>
>
>>>good enough for most people.
>>>Besides, logic alone will help in this definition. A mixture, or Alloy
>>>
>>>
>can
>
>
>>>occur in almost any proportion of one of the constituents to the
>>>
>>>
>other(s),
>
>
>>>but Silicon Carbide ALWAYS comes in a one-to-one count of atom-to-atom,
>>>
>>>
>ie,
>
>
>>>SiC.
>>>The concept of "shared electrons" as a requirement for chemical
>>>
>>>
>compounds
>
>
>>>was shot down when several "noble gas" compounds were created.
>>>He also seemed to almost ignore the contribution of Silicon to the
>>>
>>>
>Oxygen
>
>
>>>grab that takes place in the participation of SiC in glaze reduction.
>>>
>>>
>The
>
>
>>>Silicon grabs Oxygen from any of several glaze materials to form more
>>>Silica (SiO2) a normal glaze ingredient, when the Carbon takes up Oxygen
>>>
>>>
>to
>
>
>>>make the CO2.
>>>Bill, sitting out a very soggy Friday on Persimmon Hill.
>>>
>>>
>>>At 03:28 PM 2/25/2003 -0500, you wrote:
>>>
>>>
>>>>P.Southwood:
>>>>
>>>>Silicon Carbide is technically an "alloy" not a compound in the usual
>>>>sense, ie, exchange or co-ordination of outer-shell electrons. so the
>>>>carbon is really graphite (groupings of carbon atoms) uniformly mixed
>>>>
>>>>
>with
>
>
>>>>groupings of silicon atoms.
>>>> good pots. peace. Tom B.
>>>>
>>>>
>>>Bill Aycock - W4BSG
>>>Woodville, Alabama
>>>
>>>
>>>
>>>
>____________________________________________________________________________
>__
>
>
>>>Send postings to clayart@lsv.ceramics.org
>>>
>>>You may look at the archives for the list or change your subscription
>>>settings from http://www.ceramics.org/clayart/
>>>
>>>Moderator of the list is Mel Jacobson who may be reached at
>>>
>>>
>melpots@pclink.com.
>
>
>>
>>
>____________________________________________________________________________
>__
>
>
>>Send postings to clayart@lsv.ceramics.org
>>
>>You may look at the archives for the list or change your subscription
>>settings from http://www.ceramics.org/clayart/
>>
>>Moderator of the list is Mel Jacobson who may be reached at
>>
>>
>melpots@pclink.com.
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
>
>
>
Edouard Bastarache wrote:
>Hello Tom,
>
>until recently some carborandum was produced in Shawinigan, Quebec,
>an industrial region you certainly know of. From what I learned from workers
>the temperature used was 4,000 F.
>
>
>Later,
>
>Edouard Bastarache
>
>----- Original Message -----
>From: Tom Buck
>
>Hey Bill A!
> good to hear from you; it's been awhile. Yes, my Handbook also
>lists SiC as a chemical with a specific mole weight, SiC.
> Please, Bill, give me an idea of how is SiC made, from what forms
>of Silicon and Carbon, at what temperature, in what state (solid, liquid,
>gas?). I would expect that to get a 50/50 compound, the two components
>would have to be molten, or a silicon compound liquid at reasonable
>temperatures would react with a form of carbon to produce the solid
>crystals of SiC. My chem dictionary says SiC is made by heating carbon
>and silicA in an electric furnace to a moderate temperature, whereas
>2200 oC/4000 oF seems more likely.
> and yes, Bill, there is some activity on the part of Silicon to
>bring about reduction of glaze components, but this wouldn't cause
>the cratering effect posed by the original query, only the formation of
>Carbon Monoxide gas would do that. besides, solid/solid chemical reactions
>are difficult to achieve and even then quite slow. Mobile gas molecules
>would achieve a greater effect.
> anyway, I am pleased you have posted to Clayart again.
>be well. peace. Tom.
>
>On Fri, 28 Feb 2003, Bill Aycock, W4BSG wrote:
>
>Tom was mostly right, but not about the condition of Silicon Carbide as
>
>
>a mixture or "allow, not a compound. The Handbook of Chemistry and Physics
>lists it as a compound, and gives a "heat of formation" for it, and that
>
>
>is good enough for most people.
>Besides, logic alone will help in this definition. A mixture, or Alloy
>
>
>can occur in almost any proportion of one of the constituents to the
>
>
>other(s),but Silicon Carbide ALWAYS comes in a one-to-one count of atom-to-atom,
>
>
>ie, SiC.
>The concept of "shared electrons" as a requirement for chemical
>
>
>compounds was shot down when several "noble gas" compounds were created.
>He also seemed to almost ignore the contribution of Silicon to the
>
>
>Oxygen grab that takes place in the participation of SiC in glaze reduction.
>
>
>The Silicon grabs Oxygen from any of several glaze materials to form more
>Silica (SiO2) a normal glaze ingredient, when the Carbon takes up Oxygen
>
>
>to make the CO2.
>
Bill, sitting out a very soggy Friday on Persimmon Hill.
>At 03:28 PM 2/25/2003 -0500, you wrote:
>
>
>>>>P.Southwood:
>>>>
>>>>Silicon Carbide is technically an "alloy" not a compound in the usual sense, ie, exchange or co-ordination of outer-shell electrons. so the carbon is really graphite (groupings of carbon atoms) uniformly mixed with groupings of silicon atoms.
>>>>
>> good pots. peace. Tom B.
>>
>>
>>>Bill Aycock - W4BSG
>>>Woodville, Alabama
>>>
>>>
>>>
iandol on tue 4 mar 03
Dear Jim Tabor
You need to get into the literature base on the production of synthetic =
gemstones to find out more about these processes. A lot of it may be in =
German because much of the industry is based in Switzerland. Or you may =
get more information from companies who refine Silicon and grow crystals =
for the IT industries. As I said in a previous post, SiC is a good =
diamond substitute. Impossible to distinguish between the two gems =
without the proper test gear which measures electrical and thermal =
conductivity.
Vacuum refining is not a new process, been around for forty years to my =
knowledge. A Co. I worked for installed a vac refining set up to create =
new steel alloys soon after I left them in 1959. ViaVac of Wishaw were =
involved in these and other developments in the mid sixties as well.
The World is an Amazing Place
Best regards,
Ivor.
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