Hi hatem,
Good day, and thanks for your question.
Ceramic coatings are highly heat resistant and are used in the
bodies of rockets and ships. I've spent a couple hours of intensive
research, and consolidated the process of ceramic coating.
First, you have to make a ceramic slurry. This slurry consists of
* Metal Oxide powder (either mullite or rulite ore), which is the base
material
* Solvent: Water
* Dispersant which reduces inter-particle friction during mixing. A
commonly used dispersant is Darvan 821A
* An anti-foaming agent such as 1-butanol, which reduces the amount of
air bubbles formed during mixing.
The basic procedure behind ceramic coating is germinating and growing
a ceramic heat barrier coating in a deposition chamber by vapor
condensation of ceramic material on a substrate to be covered.
Two vaporization crucibles are placed in a deposition chamber, one of
crucibles containing the ceramic material (slurry), and the other
crucible containing air, xenon, krypton, argon, helium and carbon
monoxide
The ceramic material is continuously vaporized.
Simultaneously, the air is intermittently vaporized so as to produce
regerminations of the ceramic during its deposition.
The gaseous mixture interacts with chemical components present in the
vapor phase in the deposition chamber, and ceramic deposited to cause
regermination of the ceramic during deposition.
The key elements present in air which contribute to the deposition of
the ceramic material are carbon, nitrogen, oxygen, hydrogen, silicon,
chlorine, bromine, fluorine and iodine.
The gaseous mixture interacts physically by a process of adsorption on
the surface of the deposited ceramic.
Another way of preparing a ceramic coat on a substrate (either
chromium or nickel) is by heating. The process is as follows:
A frit composition is deposited on a substrate and then heated to form
a ceramic coat from the frit composition. Stainless steel is not
sufficiently electrochemically active to be coated by electrophoresis.
The substrate is covered by a compound of molybdenum, that is
water-soluble by contacting said substrate for 15 seconds to 30
minutes with an aqueous solution of the molybdenum compound maintained
at about 125 F to about 200 F and containing from about 0.5% to about
10% by weight of molybdenum.
The workpiece is then heated to a temperature of 1000 F to 1800 F for
about 1 minute to about 30 minutes.
Heating decomposes the compound of Molybdenum and converts it to it's
oxide, a film of which forms over the workpiece
Substitutes for molybdenum are chromium, cobalt, copper, manganese,
vanadium, iron, nickel, zinc and tungsten.
References
----------
Ceramic Slurry Composition
http://www.mme.wsu.edu/~reu/Lancepresent/sld005.htm
Ceramic heat barrier coating having low thermal conductivity, and
process for the deposition of said coating
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1='6432478'.WKU.&OS=PN/6432478&RS=PN/6432478
Preparation of nickel and chromium substrates for ceramic coating
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1='3,962,490'.WKU.&OS=PN/3,962,490&RS=PN/3,962,490
I'm sure this answered your question. If you have any clarifications,
then feel free to ask.
Cheers,
aditya2k
Search terms
ceramic coating
ceramic coating manufacturing process
ceramic manufacture raw materials
composition of ceramic coat |
Clarification of Answer by
aditya2k-ga
on
18 Aug 2002 07:18 PDT
Hi hatem,
First of all, I would like to request that when you use this
service in future, please don't rate the answer if you have a
clarification.
Coming to your clarification. In your question, you asked for
ceramic coat, and I've provided the process for it. In fact, it is a
patented process, in case you haven't visited the link. As far as 12
raw materials are concerned, there are 12 natural raw materials, and
11 artificial raw materials. It is used in the manufacture of ceramic
for tiles, articles etc.. However, since you mention it, I'm going to
post information about it.
Natural Raw Materials : Spodumene (Li2O3 - Al2O3 - 6SiO2), Clay (Al2O3
- 2SiO2 - 2H2O), Pyrophyllite (Al2O3 - 4SiO2 - H2O), Flint (SiO2),
Nepheline Syenite (K2O - 3Na2O - 4Al2O3 - 9SiO2 + Feldspar), Whiting
(CaCO3), Magnesite (MgCO3), Talc (3MgO - 4Si2 - H2O), Zircon (ZrO2 -
SiO2), Feldspar (K2O or Na2O - Al2O3 - 6SiO2), Borax (Na2O - 2B2O3 -
10H2O), Beryl (BeO - Al2O3 - 6SiO2)
Artificial Raw Materials: Alumina (Al2O3), Zinc Oxide (ZnO), Litharge
(PbO), Lead Zirconate (PbO ZrO2), Iron Oxide (Fe2O3), Tin Oxide
(SnO2), Boron Nitride (BN), Silicone Carbide (SiC), Titanium Carbide
(TiC), Cobalt Oxide (CoO), Barium Titanate (BaO TiO2)
Procedure (I)
1. The high-purity raw materials are mixed in a ball mill and then
formed in a hot press.
2. The materials are processed to the desired shape.
3. Lapping, a type of polishing, is performed to create the final
product. Advanced polishing technology is essential to achieve the
required smoothness (surface roughness of no more than 0.05) and to
assure that no effects of mechanical strain remain.
4. Sputtering can also be performed to create an insulating coating.
Process (II)
1. The raw materials are thoroughly mixed then calcinated to remove
gases and trigger ferrite transformation.
2. The materials are pulverized into fine particles.
3. A binder is added and the material is dried and made into a
high-fluidity powder.
4. The powder is then pressed into pieces of the desired shape.
5. The pieces are sintered at a temperature of 1,200¡î to 1,400¡î.
6. Lasty, the pieces are finished by polishing to the desired shape
and dimensions. After sintering, hot isostatic pressing (HIP) can be
preformed to raise the material's density and thereby further enhance
its properties.
If even this is not enough, then please be more elaborate with what
you want. For example, what kind of materials do you want to coat.
aditya2k
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