Technical (or advanced) ceramics is a fairly loose term and
covers a large and varied group of materials. There is no
strict definition of a technical ceramic, but it includes
ceramics with superior mechanical, electrical, thermal,
biological and chemical properties. Materials that are broadly
accepted to come under the "technical ceramics" umbrella
include wear-resistant ceramics, electronic components and
electrical insulators, as well as ceramics used in coatings and
automotive catalysts.
There are a number of raw materials used in advanced
ceramics production, but alumina is the most important by
volume, accounting for 70-80% of the materials used depending
on whether it is in its purest form or mixed with other oxides
(Figure 1). High-alumina ceramics provide high
strength, hardness and resistance to impact, corrosion,
abrasion and temperature and have excellent electrical
isolation. Other important raw materials include zirconia,
yttrium and rare earth oxides, silicon carbide, silicon nitride
and boron carbide.
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Figure 1: Materials used in
technical ceramics in 2014 (%)
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Source: Almatis
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Technical ceramics raw materials
Alumina
Most alumina used in ceramics is produced via the Bayer
process but small amounts of high purity material are produced
by other routes, which may include the Bayer process in the
early stages. Alkoxide, aluminium sulphate derivatives or
hydrates made from 99.99% pure metal are also used. Powders
derived from these sources are up to 10 times more expensive
than Bayer-process alumina.
There is nearly 11m tpa non-metallurgical alumina (calcined
and hydrate) capacity held globally, but only a small
proportion of this material meets the specifications for use in
advanced ceramics. The main producers of calcined alumina
suitable for use in this application include
Germany-headquartered companies Almatis, Martinswerk (which was
acquired by US-based Huber Engineered Materials in December
2015) and Nabaltec as well as France-based Alteo,
Japan’s Showa Denko, South Korean producer, KC
Corp. and AluChem, which is based in the US.
Leading producers of ultra high-purity alumina, which is
used in some niche ceramics applications such as synthetic
sapphire, include Hebei Pengda New Material (China), Baikowski
(France and the USA), Sumitomo Chemical (Japan and South Korea)
and Sasol (US). In addition, Australia-baed Altech Chemicals
Ltd and Canada’s Orbite Technologies Inc. are
developing ultra high-purity alumina projects which are
expected to come online over the next few years.
Zirconia
Zirconia (ZrO2) is obtained by processing zircon
(ZrSiO4) or baddeleyite (natural zirconia). Four
process routes are currently used commercially to extract
zirconia from zircon sand: chemical precipitation; alkaline;
fused; and plasma methods. Material produced via each process
can be used to make advanced ceramics, but chemical zirconia
accounts for the highest proportion.
Zirconia ceramics are used for their conducting
characteristics, for example in electronic sensors, or
structural properties in a range of engineering applications,
including wear parts, ceramic coatings and as high-strength and
high-toughness ceramic components. The electrical uses of
zirconia ceramics are well established, whereas structural
applications are less developed but offer promising growth
prospects for the zirconia market.
China is the leading zirconia producer globally, with nearly
60% of total production capacity. The largest supplier in the
world is Imerys Advanced Materials Yingkou, a subsidiary of
Imerys Fused Minerals, itself a division of French industrial
minerals group Imerys SA. Imerys Advanced Materials Yingkou is
based in Liaoning, China.
Other leading producers of zirconia suitable for use in
advanced ceramics include Saint-Gobain (China, France and the
US), Guangdong Orient Zirconic (China), Daiichi Kigenso Kagaku
Kogyo (Japan), Tosoh (Japan), Nippon Denko (Japan), MEL
Chemicals (UK and US), TAM Ceramics (US), Washington Mills
Electro Minerals (UK and US), and Zircoa (US).
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Cut above: Advanced zirconia ceramics can be used
to make kitchen tools,
such as zirconia oxide ceramic knives. (Bill
Smith, via Flickr)
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Yttria and rare earth oxides
The main application for rare earths in advanced ceramics is
yttrium oxide (yttria) as a stabiliser in yttria-stabilised
zirconia (YSZ), for use in large number of applications,
including thermal barrier coatings in industrial gas and
aviation turbines; fibre-optic connectors; oxygen sensors for
automotive fuel control; fuel cell components; and dental and
other biomedical applications. Yttrium oxide can be substituted
with other stabilisers such as calcia or magnesia, but the
substitutes generally impart lower toughness.
Yttrium is also used as a sintering agent in the production
of silicon nitride materials for high-temperature/endurance
applications such as gas turbines, automotive engine parts,
bearings and machine tools. Meanwhile, neodymium oxide is used
as a component in precious metal ceramic capacitors for
electrical applications. Cerium, lanthanum and praseodymium
also have some applications in advanced ceramics, but by far
the most widely used rare earth oxide (REO) is yttria, at over
60% of the REO total in this market. In addition, yttria is
used in certain grades of silicon aluminium oxynitrides
(SiAlONs).
China is the world’s largest producer of REOs
at nearly 90% of the total and is the largest consumer of the
minerals in ceramics applications. The leading producers in
China include Baogang Group, Aluminium Corp. of China
(Chinalco) and Ganzhou Mining.
Advanced ceramic producers
Most consumption of raw materials for advanced ceramics
production takes place in Europe, North America and Asia, where
the major manufacturers are located.
CeramTec of Germany, which was acquired by the European
private equity firm Cinven in August 2013 for €1.49bn
($166bn**), is one of the leading producers. CeramTec was
formerly part of US-based chemicals producer Rockwood Holdings,
but was divested when Rockwood (itself later acquired by
Albemarle Corp.) refocused on its lithium activities. The bulk
of the company’s production takes place in
Germany, but CeramTec also has plants in the US and China.
CeramTec has a current portfolio of over 10,000 different
products, components and parts made of advanced ceramics and
ceramic materials.
US-headquartered CoorsTek has technical ceramics plants in
Europe and Asia as well as in North America. The company
manufactures ceramic components for defence, medical,
automotive, semiconductor, aerospace, electronics, power
generation, telecommunications and other high-technology
applications. It has increased its capabilities following a
series of expansions and purchases since 2007, including the
acquisition of most of Saint-Gobain’s advanced
technical ceramics facilities for $245m in 2010, the technical
ceramics division of BAE Systems in 2011 and UK-based technical
ceramics producer Dynamic-Ceramic in 2013.
Kyocera of Japan is a leading producer of ceramic components
for various applications, including cutting tools, ceramic and
sapphire substrates, medical materials, ceramic packages for
light emitting diodes (LEDs), kitchen tools and substrates for
high-resolution print heads.
Morgan Technical Ceramics is a subsidiary of UK-based Morgan
Advanced Materials (formerly Morgan Crucible Co.), and produces
a range of structural ceramic components, ceramic coatings,
piezo ceramic components, sensors, ceramic cores, capacitors
and other products. Morgan Advanced Materials operates from a
number of plants globally, including North America, Europe,
South America, Oceania, Asia and the Middle East.
Germany-headquartered Lapp Insulators is a leading producer
of high-voltage insulators. The company was headquartered in
the US until its acquisition in August 2011 by Quadriga
Capital. In October 2015, Lapp was purchased by the PFISTERER
Group, a supplier and systems provider for energy
infrastructure. High-voltage insulators are produced in
Germany, the US, China, Romania and Poland.
Market applications
Applications for technical ceramic products can be broadly
divided into structural ceramics and functional ceramics.
Structural ceramics are prized for their mechanical properties,
including high strength, toughness, hardness and creep
resistance. These materials must be very hard, dimensionally
stable and strong. Depending on the application, these ceramics
must also maintain these properties at high temperatures.
Within the structural ceramics market there are a number of
products and applications. The main markets by volume are
grinding media, ceramic rollers, catalytic substrates and
chemical processing. Grinding media are the single largest
application in wear-resistant ceramics by volume, accounting
for over a third of the sector. Lower volume but higher value
applications include synthetic sapphire, ceramic coatings,
bioceramics, ceramic armour and cutting tools.
Functional ceramics are prized for their superior electric,
magnetic and optical properties. The main applications for
functional ceramics include electronics, high-voltage
insulators and spark plugs. Advanced ceramics are used in
electronic substrates, microchips, pressure sensors,
piezoelectrics, resistors and inductor bodies.
In terms of raw materials, very high purity aluminas are
widely used and, because of this, the market for electronic
substrates is the largest by value for technical ceramics.
Increasing sophistication of electronic components has led to
growing use of purer, and therefore more effective, aluminas in
order to insulate components from the waste heat generated.
Over the next five years, structural ceramics are expected
to show the highest growth rates within the technical ceramics
sector – growing in line with the forecast global GDP
rate of 3.3% per annum.
The main market driver behind structural ceramics is the
grinding media segment, which is forecast to grow slightly
under the market average. Catalytic substrates, chemical
processing aids and ceramic coatings are all expected to grow
in excess of the GDP forecast out to 2021.
However, by far the highest growth rate for structural
ceramics is forecast to be in synthetic sapphire production,
which Roskill projects will grow by 15%py over the next five
years. This is due to the use of synthetic sapphire substrates
in the LED lighting market. If sapphire finds a large role in
the smartphone sector – for instance in screens
– then demand growth could be much higher than
this.
Growth in the functional ceramics sector is likely to be
below that of structural ceramics, as one of the largest
applications – high-voltage insulators – is
forecast to decline out to 2021. This is because ceramic-based
high voltage (HV) insulators have come under increasing
competition from glass and polymer-based insulators, which
offer equivalent mechanical properties at a lower weight.
Electronic ceramics, meanwhile, are expected to grow well in
excess of the global GDP forecast due to their link with the
consumer electronics sector.
Sources:
Non-Metallurgical Bauxite & Alumina: Global Industry,
Markets & Outlook to 2021 (published February 2016), Rare
Earths: Market Outlook to 2020 (March 2015), Zirconium Oxide,
Chemicals & Metal: Global Industry & Markets (October
2014), Roskill Information Services.
*Jessica Roberts is a senior analyst at Roskill
Information Services in the UK.
**Conversion made March 2016