How are ceramic chips manufactured?

[Matt J. McCullar]

I often deal with chips that are decades old by now, and I've always
wondered what goes into the recipe for the ceramic casing. What are the raw
materials, how is it produced, etc.?

Also, how are components in general labled with the letters and numbers?
It's very heavy-duty material, as very few cleaning materials will
obliterate it.

 

[Tim Williams]

"Matt J. McCullar" <mccullar@flash.net> wrote in message
news:Yj2bf.6342$Kv.5273@newssvr22.news.prodigy.net...

I often deal with chips that are decades old by now, and I've always
wondered what goes into the recipe for the ceramic casing. What are
the raw materials, how is it produced, etc.?

Barium carbonate, titanium dioxide and dopants, lead for instance. The rest
applies to pretty much any technical ceramic, from capacitors to ferrites to
high-temperature superconductors.

Sufficiently pure materials are blended with a binder (usually something
organic like a gum which burns out on firing, since any that remains, for
instance the time-tested binder clay, will affect the material's final
composition), pressed, molded or cast into shape and fired slowly up to just
below the melting point, cooled slowly and ground to final shape. Higher
performance materials may be calcined as powder, pulverized, sometimes
calcined a second time and pulverized, and only then is binder added and the
final shapes fired.

Also, how are components in general labled with the letters and numbers?
It's very heavy-duty material, as very few cleaning materials will
obliterate it.

I would guess titanium dioxide bonded into the epoxy case surface, which
itself is probably black due to graphite or lampblack. Other markings of
course are laser printed, especially those shiny and fucking invisible
ones...

Tim

--
Deep Fryer: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

 

[Boris Mohar]

On Sat, 5 Nov 2005 08:54:07 -0600, "Tim Williams" <tmoranwms@charter.net>
wrote:

itself is probably black due to graphite or lampblack. Other markings of
course are laser printed, especially those shiny and fucking invisible
ones...

Tim

Especially when conformably coated. Cheap bastards.



Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

void _-void-_ in the obvious place

 

I realise it's a bit OT, but where do the world's Barium, Americium,
Osmium, Tungsten, and all the other wierd rare metals come from? So
far there's been no "HEAVY ENGINEERING: Tungsten mines!" on the
Discovery channel.

In the specific case of Osmium (sticks in my head, because - ) it's
worth about 80 times more than gold, so is it dug up in hi-security?
Or is the somewhat limited market security enough?

------------------------------------------------------------------------

if love is a drug, then, ideally, it's a healing, healthful drug... it's
kind of like prozac is supposed to work (without the sexual side
effects and long-term damage to the brain and psyche)

 

[Tim Williams]

<greenaum@BOLLOCKSyahoo.co.uk> wrote in message
news:436d0f2d.12415106@news.cable.ntlworld.com...

I realise it's a bit OT, but where do the world's Barium, Americium,
Osmium, Tungsten, and all the other wierd rare metals come from? So
far there's been no "HEAVY ENGINEERING: Tungsten mines!" on the
Discovery channel.

Heh, good point.

Barium comes mostly from barite (barium sulfate) and some witherite (barium
carbonate). Barite of course is probably familiar as the "chalky milkshake"
that gives the gastrointestinal tract good x-ray visibility. Barium is
nicely poisonous but this works because barium sulfate is a highly insoluble
salt of a strong mineral acid and nothing much can displace it so it just
goes right on through.

For processing, they have to get it into a more useful form to seperate it
on a large scale during processing, but I don't have the slightest idea how
they'd do that. Possibly they could mine selectively enough to get a like
80% rich ore or something, then reduce the sulfate to sulfide with carbon at
a yellow heat. From there, you'd oxidize the sulfide to sulfur (byproduct),
leaving barium hydroxide, chloride, or whatever else you choose.

The barium carbonate I have (ceramic grade) definetly has sulfide
impurities, because when I make barium chloride with it, it stanks.

Tungsten is probably mined like any other heavy metal, seperated from gangue
by flotation and/or density (tungsten minerals are dense), acidified (to
free tungsten hydroxide, i.e., tungstic acid) then leached with a basic
solution, since sodium tungstate is soluble. The same would apply to
molybdenum, whose chemistry is similar AFAIK. Then you just reduce it to
metal, and, uh, well it's hard to melt into ingots so you'll mostly have to
live with powder. ;-)

Americium of course is seperated from fission reactors, where uranium
undergoes neutron absorbtion and other nuclear reactions which increase Z
(atomic number). After some time in the pile, the fuel is dissolved and the
americium (and others) is seperated chemically.

In the specific case of Osmium (sticks in my head, because - ) it's
worth about 80 times more than gold, so is it dug up in hi-security?
Or is the somewhat limited market security enough?

Heh, gnaw- platinum group specimens are probably worth more to museums and
private mineral collections than on the market. Such items are exceedingly
rare. A lot of the rare elements, for example selenium, tellurium, PGMs,
etc. are a result of refinement, usually by a very selective process such as
electrorefining (or electrowinning) or the brutal chlorination of something
like molten gold (yum, chlorine at 2000°F!). Freshly smelted copper for
example oftem holds impurities of Se, Te, As, Ag and so on. If you dissolve
this through a solution containing only Cu ions (especially with some
chloride ions, which *loves* silver ions and will precipitate it), 99.9%+
purity copper will plate out, leaving the impurities either in solution (not
so good) or as a sludge (very good). Further refining on that yields your
trace elements.

Cadmium was discovered as a fume inside zinc smelter stacks. It has similar
chemistry to zinc so is found in zinc ores, but since it has a lower boiling
point, not much would be condensed off the smelter, leaving it to go up in
smoke, occasionally sticking to the flue. A few other elements work the
same way.

Eh, that was a much longer post than such a diagonal comment deserved...oh
well...

If you want to learn more, a good historical reference is De Re Metallica.
Doesn't cover the less common and/or hard to win elements, but hey, it was
the 16th century. ;-)

Tim

--
Deep Fryer: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

 

Actually I've found me a couple of really good periodic table sites,
tho you've added things they didn't say. Thanks a lot for that utterly
useless knowledge, the kind I treasure most!

http://www.element-collection.com/

Build real live periodic tables, with the noble gases in electrified
tubes so they glow, and actual samples of most elements. For beryllium
they have the metal, and a hi-voltage ceramic beryllium oxide
insulator used in industry. Etc. Extremely interesting. Lithium has
the metal under oil, and a few lithium carbonate anti-loony pills.

Anyway sorry to answer my own question, but you might find it an
interesting site. Prices start from $40,000!

------------------------------------------------------------------------

if love is a drug, then, ideally, it's a healing, healthful drug... it's
kind of like prozac is supposed to work (without the sexual side
effects and long-term damage to the brain and psyche)