> High Temperature Materials
SHAPAL - BORON NITRIDE - BORON NITRIDE SILICA MIX (BNS26) -
ALUMINA (96% machinable) -QUARTZ - HIGH DENSITY GRAPHITE -
CARBON CARBON COMPOSITE
Ceramisis have a production facility dedicated to advance
technical ceramic and graphite component manufacture, in a wide
range of machinable technical ceramics and high density
graphites including Macor, Shapal, Boron Nitride, Boron Nitride
Silica mix (BNS26), Alumina (96% machinable), Quartz and a very
wide range of High Density Graphite and Carbon Carbon Composite
grades. We can also supply machinable ceramics such as Macor,
Shapal, Boron Nitride, Boron Nitride Silica mix (BNS26), Alumina
(96% machinable), and High Density Graphite and Carbon Carbon
Composite, in rod or plate form, for customers to produce their
own technical ceramic, high density graphite and carbon carbon
composite components. Technical ceramics, high density graphites
and carbon carbon composites are ideal for use in UHV Thin Film
Vacuum Deposition and Etch systems due to their low outgassing
Ceramisis also supply Ceramic and graphite components produced by
Chemical Vapour Deposition (CVD), such as Solid Pyrolytic graphite (PG)
and solid Pyrolytic Boron Nitride (PBN), and can also produce composite
products made from these to materials combined, such as heater elements.
We produce components such as boats, crucibles and heaters, which are
also well very suited to Ultra High Vacuum (UHV) applications due to
their very high purity, low outgassing and high operating temperatures.
ceramics, such as Macor, Shapal, Boron Nitride, Boron Nitride Silica mix
(BNS26), Machinable 96% Alumina, and high density graphite, components are
produced using conventional machining techniques from stock bar, rod and
plate. No post firing is required after the components are machined.
CVD materials such as Pyrolytic Graphite (PG) and Pyrolytic Boron
Nitride (PBN) components are produced at very high temperatures by
depositing material onto a substrate or mandrel. Post machining is
possible although the deposited thickness of the material is normally
only a few millimetres.
Ceramisis also supply a complete range of high temperature asbestos free
ceramic textiles, in cloth, rope, sleeve, blanket and yarn form. We can
offer the well known Dalfratex range of ceramic textiles.
is a machinable glass
ceramic and easily machined with conventional metal working tools. It is
an ideal prototyping material for use in a vacuum environment at low or
high temperature. Continuous use temperature is 800 C with short
exposure up to 1000C, and the coefficient of thermal expansion matches
most metals. Macor has zero porosity, a very low thermal conductivity
and good electrical insulation properties, and so is ideal for in vacuum
heater isolators and supports. It does however have poor resistance to
Click here for Macor material
is machined with diamond tooling and has high mechanical strength and
high thermal conductivity. It has very good resistance to thermal shock
and is based on the worlds first translucent aluminium nitride ceramic.
Shapal ceramic unique characteristics make it suitable for a wide range
of applications in the vacuum and nuclear industries. It has zero
porosity, low our gassing rates, is not affected by most etch plasmas or
ionizing radiation and easily joins to its self or other materials. Its
maximum operating temperature is 1900C.
Click here for Shapal material
Boron Nitride -
Boron nitride is a unique material. it offers outstanding thermal
conductivity, excellent dielectric strength, very good thermal shock
resistance, is self lubricating and is easily Machinable. This material
is an advanced synthetic ceramic available in powder, solid, liquid and
aerosol spray forms. In an oxidizing atmosphere it can be used up to
900°C. However, in an inert atmosphere some grades can be used as high
as 3000°C. Grades are available with a very low porosity and ultra high
strength for use in semiconductor processing and mechanical
applications. Great care must be taken when using boron nitride
components over 1000C in high vacuum. Some grades contain calcium
carbonate binders that will liquefy around 1000C in high vacuum causing
great damage to the vacuum chamber and pumping system. We have a binder
free 100% boron nitride grade that we recommend for use above 1000C in
high vacuum. Boron Nitride is Hygroscopic and will absorb moisture if
left exposed to the atmosphere. This moisture must be baked out at low
temperature before operating at high temperature.
Click here for Boron
Nitride material properties
Silica Mix (BNS26) - BNS26 is a unique material combining
Boron Nitride with Silica, essentially giving some of the best
properties of both Macor and Boron Nitride. BNS26 is a hydrophobic
advanced ceramic and is resistant to moisture (unlike boron nitride). It
is suitable for the most severe electrical applications, is an excellent
refractory material up to 1400C, and has excellent resistance to thermal
shock. It is an ideal material for heater element supports and bases.
Click here for M26 material properties
Machinable) - useable continually to 1650°C
with a melting point of 1870°C, 96% Alumina machinable ceramic is
manufactured from high purity alumina by a unique process. Unlike
standard alumina this unique manufacturing process enables our 96%
Alumina to be machined with conventional tooling on standard machine
shop equipment. No post heat treating after machining is required
offering the convenience and economy of an in house capability for
alumina parts. The chemical, thermal and electrical properties of our
96% Alumina machinable ceramic are equivalent to standard high alumina
ceramics, with good resistance to thermal shock. Our Alumina 96%
machinable ceramic is available in various standard rod sizes up to
Ø3.5" x 12" long,
and plates up to 6" x 6" x ¾".
Click here for Alumina (96%
machinable) material properties
We supply quartz rods and tubes for use as element
supports. Partial machining is possible to put holes and slots into the
quartz rods and tubes, making them ideal for use as tungsten element
supports (bespoke tungsten elements are also produced by Ceramisis).
Quartz is ideal for use in UHV and has very low thermal conductivity it
is also transparent to infra red, and so is slow to heat, making it an
ideal material for element supports and covers.
Graphite - High density
graphite and carbon carbon composite are ideal materials for
in vacuum heating elements. Chemically the same, high density
graphite and carbon carbon composite materials are very inert,
get stronger with temperature, has low expansion coefficient
and will not seize after heating. High density graphite is brittle
but inexpensive and machined
conventionally from large blocks, therefore very large sized
graphite elements can be produced in a variety of shapes and sizes.
Our high strength ultra fine grained graphite enables small
very intricate elements to be manufactured also.
Graphite has a low expansion coefficient and is not
degraded by constant heating and cooling, and also gets
stronger as its temperature increases. Its low resistivity means it requires high current power supplies
and therefore large feedthroughs and cables which can be
expensive. It can operate over 2000 °C in an
inert atmosphere or
in vacuum and <500°C
if oxygen is present. Graphite elements have the ability to take
very high current density, and therefore very fast ramp up
times can be achieved. Its relatively high specific heat
capacity means that cool down times in vacuum can be quite
long. Apart from reacting with oxygen from 500C, graphite is
otherwise very inert and can therefore operate in very
corrosive or aggressive atmospheres without degradation.
Particle contamination and open porosity can be a problem
with graphite, but this can be overcome with coatings, or
impregnations detailed below. Graphite elements are suitable
for UHV applications, but must undergo initial out-gassing
process due to its open porosity.
Click here for High Density
Graphite material properties
Carbon Carbon Composite is much stronger than graphite and is not
brittle due to its fibrous grain structure. Carbon Carbon Composite
elements can therefore be made in very thin sections, typically 1mm
thick, which overcome a number of the problems associated with high
density graphite elements. Thin carbon carbon composite elements have a
much higher resistance than high density graphite elements, allowing
lower current, higher voltage power supplies to be used , and smaller
power feedthroughs and cables, thereby reducing costs. The lower mass of
the thin carbon carbon composite elements means that they heat up much
quicker and also cool down much faster in vacuum. Carbon Carbon
composite is produced in sheets (typically 1m²) of various thicknesses
from 1.0mm to 30mm. Modern CNC machining techniques mean that carbon
carbon composite elements can be produced very cheaply. We stock
standard designs of carbon carbon composite elements from Ø1" to Ø6"
which are manufactured in quantity and therefore very cost effective.
Carbon carbon composite also has extremely low thermal conductivity
which is beneficial in reducing heat loss through the power contact
points, thereby increasing element uniformity. This low thermal
conductivity also means that carbon carbon composite is ideal for use as
a heat shield, both in vacuum and also in inert atmosphere.
here for Carbon Carbon Composite material properties