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Material Test Compressive Yield Strength (psi)
Ceramic
99.9% Al2O3 ASTM C773 392,000 Mechanical
Metal
316 Stainless Steel Typical Value 30,000Source: CoorsTek, Inc., Golden, Colo., www.coorstek.com.
Note: Although we have no reason to doubt the accuracy of the data presented, this information is offered for comparison only. CoorsTek and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
Key Features/Benefits of Some Advanced Technical Ceramics
Aluminum Oxide (Al2O3). Aluminum oxide (alumina) is the workhorse of advanced technical ceramics. It has good mechanical and electrical properties, wear resistance and corrosion resistance. It has relatively poor thermal shock resistance. It is used as an electrical insulator for a number of electrical and electronic applications, including spark plug insulators and electronic substrates. It is also used in chemical, medical and wear applications.
Zirconium Oxide (ZrO2). Zirconium oxide has the highest fracture toughness of any advanced technical ceramic. Its toughness, mechanical properties and corrosion resistance make it ideal for medical and selected wear applications. Its thermal expansion coefficient is very close to steel, making it an ideal plunger for use in a steel bore. Its properties are derived from a very precise phase composition. Some environmental conditions can make the material unstable, causing it to lose its mechanical properties. Its relatively low hardness and high weight also limit its broad use in wear applications.
Fused Silica (SiO2). Fused silica is an excellent thermal insulator and has essentially zero thermal expansion. It has good chemical resistance to molten metals but is limited by its very low strength. It is used for a number of refractory and glass applications, as well as radomes for missiles.
Titanium Diboride (TiB2). Titanium diboride is an electrically conducting ceramic and can be machined using electron discharge machining (EDM) techniques. It is a very hard material; however, its mechanical properties are poor. Its major use is in metallurgical applications involving molten aluminum. It is also used for some limited wear applications, such as ballistic armor to stop large-diameter (>14.5 mm) projectiles.
Boron Carbide (B4C). Boron carbide is the hardest material after diamond, giving it outstanding wear resistance. Its mechanical properties, especially its fracture toughness, are low, limiting its application. However, it is used extensively for ballistic armor and blast nozzles. Boron carbide is also a neutron absorber, making it a primary choice for control rods and other nuclear applications.
Silicon Carbide (SiC). Silicon carbide has outstanding wear and thermal shock resistance. It has good mechanical properties, especially at high temperatures. It is a semiconductor material with electrical resistivities in the 10^5 ohm-cm range. It can be processed to a very high purity. Silicon carbide is used extensively for mechanical seals because of its chemical and wear resistance.
Tungsten Carbide (WC). Tungsten carbide is generally made with high percentages of either cobalt or nickel as a second, metallic phase. These ceramic metals, or &#;cermets,&#; have wide use as cutting tools and other metal-forming tools. Pure tungsten carbide can be made as an advanced technical ceramic using a high-temperature hot isostatic pressing process. This material has very high hardness and wear resistance and is used for abrasive water jet nozzles; however, its weight limits its use in many applications.
Aluminum Nitride (AlN). Aluminum nitride has a very high thermal conductivity while being an electrical insulator. This makes it an ideal material for use in electrical and thermal management situations.
Boron Nitride (BN). Hexagonal boron nitride is a chalky white material and is often called &#;white graphite.&#; It has generally poor mechanical properties. It has outstanding high-temperature resistance (>ºC) in inert atmospheres but cannot be used above 500ºC in an air atmosphere. It is used as a high-temperature insulator and in combination with TiB2 in many ferrous and aluminum metallurgical applications.
Silicon Nitride (Si3N4). Silicon nitride has the best combination of mechanical, thermal and electrical properties of any advanced technical ceramic material. Its high strength and toughness make it the material of choice for automotive and bearing applications.
Source: Ceradyne Inc., Costa Mesa, Calif., www.ceradyne.com.
Note: Although we have no reason to doubt the accuracy of the data presented, this information is offered for comparison only. Exact properties will vary depending on the manufacturing method and part configuration, and can sometimes be tailored to meet specific requirements. Contact your component supplier for more detailed information. Ceradyne and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
Alumina represents the most commonly used ceramic material in industry. It provides superior abrasion, high temperature and chemical resistance, and is also electrically insulating. This material has an excellent cost-to-part life performance record. Purity levels are available from 85% through 99.9%. Applications include wear- and heat resistant liners, mechanical and pump seals, nozzles, semiconductor equipment components, insulators, etc.
Properties Units Test Value
Physical
Chemical FormulaAl2O3
Density, ρ g/cm3 ASTM C20 3.7-3.97 Color ivory/white Crystal Structure hexagonal Water Absorption % at room temperature (R.T.) ASTM C373 0.0 HardnessMohs
9
Hardness Knoop (kg/mm2) Knoop 100 g Mechanical
Thermal
Max. Use Temperature (in air) ºC No load cond. Thermal Shock Resistance ΔT (ºC) Quenching 200 Thermal Conductivity W/m-K @ R.T. ASTM C408 35 Coefficient of Linear
Electrical
Dielectric Constant 1 MHz @ R.T. ASTM D150 9.6 Dielectric Strength kV/mm ASTM D116 15 Electrical Resistivity Ωcm @ R.T ASTM D > Source: Ferro-Ceramic Grinding, Inc., Wakefield, Mass., www.ferroceramic.com.
Note: Although we have no reason to doubt the accuracy of the data presented, this information is offered for comparison only. Exact properties will vary depending on the manufacturing method and part configuration, and can sometimes be tailored to meet specific requirements. Contact your component supplier for more detailed information. Ferro-Ceramic Grinding and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
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Typical Aluminum Nitride (A1N) Properties
While AlN is not a new material, manufacturability developments over the past 15 years have made it an exciting and viable ceramic design option. One of the most useful applications AlN has found is in replacing beryllium oxide (BeO) in the semiconductor industry due to BeO&#;s toxicity. The thermal expansion coefficient of AlN is lower than BeO or alumina, and closely matches that of the silicon wafers used in electronics. While this was once a limitation for AlN&#;s use in electronic applications, there are now processes to metallize AlN. Electronic and structural grades of this material exist, classified as such by the thermal conductivity, which is controlled by the purity of the AlN. Pristine material is white, high-purity is tan, and a gray color indicates contaminants.
Properties Units Test Value
Physical
Chemical FormulaAIN
Density, ρ g/cm3 ASTM C20 3.25 Color white/tan/gray Crystal Structure hexagonal Water Absorption % at room temperature (R.T.) ASTM C373 0.0 HardnessMohs
5
Hardness Knoop (kg/mm2) Knoop 100 g Mechanical
Thermal
Max. Use Temperature (in air) ºC No load cond. Thermal Shock Resistance ΔT (ºC) Quenching 400 Thermal Conductivity W/m-K @ R.T. ASTM C408 82.3-170 Coefficient of Linear
Electrical
Dielectric Constant 1 MHz @ R.T. ASTM D150 8.0-9.1 Dielectric Strength kV/mm ASTM D116 15 Electrical Resistivity Ωcm @ R.T ASTM D > Source: Ferro-Ceramic Grinding, Inc., Wakefield, Mass., www.ferroceramic.com.
Note: Although we have no reason to doubt the accuracy of the data presented, this information is offered for comparison only. Exact properties will vary depending on the manufacturing method and part configuration, and can sometimes be tailored to meet specific requirements. Contact your component supplier for more detailed information. Ferro-Ceramic Grinding and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
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Typical Boron Carbide (B4C) Properties
Boron carbide is the hardest material after diamond, giving it outstanding wear resistance. Its mechanical properties, especially its fracture toughness, are low, limiting its application. However, it is used extensively for ballistic armor and blast nozzles. Boron carbide is also a neutron absorber, making it a primary choice for control rods and other nuclear applications.*
Physical
Chemical FormulaB4C
Density, ρ g/cm3 3.25 Color white/tan/gray Crystal Structure hexagonal Water Absorption % at room temperature (R.T.) ng HardnessVickers @ R.T. (GPa)
36 Hardness Knoop (kg/mm2) ng Mechanical
Thermal
Max. Use Temperature (in air) ºC Thermal Shock Resistance ΔT (ºC) ng Thermal Conductivity W/m-K @ R.T. 28 Coefficient of Linear
Electrical
Dielectric Constant 1 MHz @ R.T. ng Dielectric Strength kV/mm ng Electrical Resistivity Ωcm @ R.T ng Source: NIST, www.ceramics.nist.gov/srd/scd/Z.htm#M1P1.
Note: Typical values usually are representative of trends of values commonly found for a general class of B4C materials and are not necessarily the best or most appropriate values for any particular material. Exact properties will vary depending on the manufacturing method and part configuration, and can sometimes be tailored to meet specific requirements. Contact your component supplier for more detailed information. Ceramic Industry disclaims any and all liability from error, omissions or inaccuracies in the above chart.
* = information added by the editors; ng = not given in the original source
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Typical Boron Nitride (BN) Properties
BN is made using a hot pressing process and comes as a lubricious white solid. It can be machined using standard carbide drills. Due to its crystal structure, BN is anisotropic electrically and mechanically. It exhibits a high electrical resistance, low dielectric constant and loss tangent, low thermal expansion, chemical inertness, and good thermal shock resistance. There are several different purity levels for this material. All offer very high thermal conductivity and stability in inert and reducing atmospheres up to °C, and up to 850°C in oxidizing environments. Typical uses include vacuum components, low-friction seals, various electronic parts, nuclear applications and plasma arc insulators.
Properties Units Test Value
Physical
Chemical FormulaBN
Density, ρ g/cm3 ASTM C20 2.28 Color white Crystal Structure hexagonal Water Absorption % at room temperature (R.T.) ASTM C373 0.0-1.0 HardnessMohs
2
Hardness Knoop (kg/mm2) Knoop 100 g 25-205 Mechanical
Thermal
Max. Use Temperature (in air) ºC No load cond. 985 Thermal Shock Resistance ΔT (ºC) Quenching > Thermal Conductivity W/m-K @ R.T. ASTM C408 20 Coefficient of Linear
Electrical
Dielectric Constant 1 MHz @ R.T. ASTM D150 4.08 Dielectric Strength kV/mm ASTM D116 374 Electrical Resistivity Ωcm @ R.T ASTM D > Source: Ferro-Ceramic Grinding, Inc., Wakefield, Mass., www.ferroceramic.com.
Note: Although we have no reason to doubt the accuracy of the data presented, this information is offered for comparison only. Exact properties will vary depending on the manufacturing method and part configuration, and can sometimes be tailored to meet specific requirements. Contact your component supplier for more detailed information. Ferro-Ceramic Grinding and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
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Typical Cordierite Properties
Cordierite is mainly a structural ceramic and is often used for kiln furniture due to its extremely good thermal shock resistance. Like other structural ceramic materials, cordierite also has good thermal and electrical insulating capabilities.
Properties Units Test Value
Physical
Chemical Formula2MgO-2Al2O3-5SiO2
Density, ρ g/cm3 ASTM C20 2.60 Color tan Crystal Structure orthorhombic Water Absorption % at room temperature (R.T.) ASTM C373 0.02-3.2 HardnessMohs
7
Hardness Knoop (kg/mm2) Knoop 100 g - Mechanical
Thermal
Max. Use Temperature (in air) ºC No load cond. Thermal Shock Resistance ΔT (ºC) Quenching 500 Thermal Conductivity W/m-K @ R.T. ASTM C408 3.0 Coefficient of Linear
Electrical
Dielectric Constant 1 MHz @ R.T. ASTM D150 4.7 Dielectric Strength kV/mm ASTM D116 5.11 Electrical Resistivity Ωcm @ R.T ASTM D > Source: Ferro-Ceramic Grinding, Inc., Wakefield, Mass., www.ferroceramic.com.
Note: Although we have no reason to doubt the accuracy of the data presented, this information is offered for comparison only. Exact properties will vary depending on the manufacturing method and part configuration, and can sometimes be tailored to meet specific requirements. Contact your component supplier for more detailed information. Ferro-Ceramic Grinding and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
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Typical Graphite (C) Properties
Graphite oxidizes under (heated) use in an air (oxidizing) environment and therefore finds its use in inert and vacuum applications such as furnace insulation packages and semiconductors. This material has the same lubricious properties as boron nitride, thanks to the same crystal structure. In inert atmospheres, use temperatures can be upwards of °C.
Properties Units Test Value
Physical
Chemical FormulaC
Density, ρ g/cm3 ASTM C20 2.28 Color black Crystal Structure hexagonal Water Absorption % at room temperature (R.T.) ASTM C373 0.1-1.5 HardnessMohs
0.1-1.5
Hardness Knoop (kg/mm2) Knoop 100 g - Mechanical
Thermal
Max. Use Temperature (in air) ºC No load cond. Thermal Shock Resistance ΔT (ºC) Quenching 200-250 Thermal Conductivity W/m-K @ R.T. ASTM C408 24 Coefficient of Linear
Electrical
Dielectric Constant 1 MHz @ R.T. ASTM D150 - Dielectric Strength kV/mm ASTM D116 - Electrical Resistivity Ωcm @ R.T ASTM D 7 x 10-3 Source: Ferro-Ceramic Grinding, Inc., Wakefield, Mass., www.ferroceramic.com.
Note: Although we have no reason to doubt the accuracy of the data presented, this information is offered for comparison only. Exact properties will vary depending on the manufacturing method and part configuration, and can sometimes be tailored to meet specific requirements. Contact your component supplier for more detailed information. Ferro-Ceramic Grinding and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
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Typical Mullite Properties
Mullite is an excellent structural material due to its high temperature stability, strength and creep resistance. It has a low dielectric constant and high electrical insulation capabilities. Typical applications include kiln furniture, furnace center tubes, heat exchange parts, heat insulation parts and rollers.
Properties Units Test Value
Physical
Chemical Formula3Al2O3-SiO2
Density, ρ g/cm3 ASTM C20 2.80 Color tan Crystal Structure orthorhombic Water Absorption % at room temperature (R.T.) ASTM C373 0.0 Hardness Mohs 8 Hardness Knoop (kg/mm2) Knoop 100 g Mechanical
Thermal
Zmdy Ceramics Product Page
Max. Use Temperature (in air) ºC No load cond. Thermal Shock Resistance ΔT (ºC) Quenching 300 Thermal Conductivity W/m-K @ R.T. ASTM C408 3.5 Coefficient of Linear
Electrical
Dielectric Constant 1 MHz @ R.T. ASTM D150 6.0 Dielectric Strength kV/mm ASTM D116 9.8 Electrical Resistivity Ωcm @ R.T ASTM D 10-13 Source: Ferro-Ceramic Grinding, Inc., Wakefield, Mass., www.ferroceramic.com.
Note: Although we have no reason to doubt the accuracy of the data presented, this information is offered for comparison only. Exact properties will vary depending on the manufacturing method and part configuration, and can sometimes be tailored to meet specific requirements. Contact your component supplier for more detailed information. Ferro-Ceramic Grinding and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
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Typical Sapphire Properties
The advantages of sapphire as a design material are numerous. Extremely high use temperature, hardness, optical clarity, flexural strength and chemical resistance make it an increasingly popular choice. Applications include grocery store scanner windows, watch glasses, and countless semiconductor and aerospace/military applications.
Properties Units Test Value
Physical
Chemical Formulaα-Al2O3
Density, ρ g/cm3 ASTM C20 3.97 Color white/transparent Crystal Structure trigonal Water Absorption % at room temperature (R.T.) ASTM C373 0.0 Hardness Mohs 9 Hardness Knoop (kg/mm2) Knoop 100 g Mechanical
Thermal
Max. Use Temperature (in air) ºC No load cond. ~ Thermal Shock Resistance ΔT (ºC) Quenching 200 Thermal Conductivity W/m-K @ R.T. ASTM C408 40 Coefficient of Linear
Electrical
Dielectric Constant 1 MHz @ R.T. ASTM D150 9.3-11.4 Dielectric Strength kV/mm ASTM D116 15-50 Electrical Resistivity Ωcm @ R.T ASTM D Source: Ferro-Ceramic Grinding, Inc., Wakefield, Mass., www.ferroceramic.com.
Note: Although we have no reason to doubt the accuracy of the data presented, this information is offered for comparison only. Exact properties will vary depending on the manufacturing method and part configuration, and can sometimes be tailored to meet specific requirements. Contact your component supplier for more detailed information. Ferro-Ceramic Grinding and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
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Typical Silicon Carbide (SiC) Properties
SiC is an artificial (man-made) mineral known for its very high hardness and abrasion resistance. Common applications include pump seals, valve components, and wear-intensive applications such as rollers and paper industry retainers.
Properties Units Test Value
Physical
Chemical Formulaα-SiC
Density, ρ g/cm3 ASTM C20 3.21 Color dark gray Crystal Structure hexagonal Water Absorption % at room temperature (R.T.) ASTM C373 0.0 Hardness Mohs 9-10 Hardness Knoop (kg/mm2) Knoop 100 g Mechanical
Thermal
Max. Use Temperature (in air) ºC No load cond. Thermal Shock Resistance ΔT (ºC) Quenching 350-500 Thermal Conductivity W/m-K @ R.T. ASTM C408 41 Coefficient of Linear
Electrical
Dielectric Constant 1 MHz @ R.T. ASTM D150 10.2 Dielectric Strength kV/mm ASTM D116 - Electrical Resistivity Ωcm @ R.T ASTM D Source: Ferro-Ceramic Grinding, Inc., Wakefield, Mass., www.ferroceramic.com.
Note: Although we have no reason to doubt the accuracy of the data presented, this information is offered for comparison only. Exact properties will vary depending on the manufacturing method and part configuration, and can sometimes be tailored to meet specific requirements. Contact your component supplier for more detailed information. Ferro-Ceramic Grinding and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
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Terminology Commonly Associated with Silicon Carbide Processing
Recrystallized Silicon Carbide (RXSIC, ReSIC, RSIC, R-SIC). The starting raw material is silicon carbide. No densification aids are used. The green compacts are heated to over ºC for final consolidation. The resulting material has about 25% porosity, which limits its mechanical properties; however, the material can be very pure. The process is very economical.
Reaction Bonded Silicon Carbide (RBSIC). The starting raw materials are silicon carbide plus carbon. The green component is then infiltrated with molten silicon above ºC with the reaction: SiC + C + Si -> SiC. The microstructure generally has some amount of excess silicon, which limits its high-temperature properties and corrosion resistance. Little dimensional change occurs during the process; however, a layer of silicon is often present on the surface of the final part.
Nitride Bonded Silicon Carbide (NBSIC, NSIC). The starting raw materials are silicon carbide plus silicon powder. The green compact is fired in a nitrogen atmosphere where the reaction SiC + 3Si + 2N2 -> SiC + Si3N4 occurs. The final material exhibits little dimensional change during processing. The material exhibits some level of porosity (typically about 20%).
Direct Sintered Silicon Carbide (SSIC). Silicon carbide is the starting raw material. Densification aids are boron plus carbon, and densification occurs by a solid-state reaction process above ºC. Its hightemperature properties and corrosion resistance are superior because of the lack of a glassy second phase at the grain boundaries.
Liquid Phase Sintered Silicon Carbide (LSSIC). Silicon carbide is the starting raw material. Densification aids are yttrium oxide plus aluminum oxide. Densification occurs above ºC by a liquid-phase reaction and results in a glassy second phase. The mechanical properties are generally superior to SSIC, but the high-temperature properties and the corrosion resistance are not as good.
Hot Pressed Silicon Carbide (HPSIC). Silicon carbide powder is used as the starting raw material. Densification aids are generally boron plus carbon or yttrium oxide plus aluminum oxide. Densification occurs by a simultaneous application of mechanical pressure and temperature inside a graphite die cavity. The shapes are simple plates. Low amounts of sintering aids can be used. Mechanical properties of hot pressed materials are used as the baseline against which other processes are compared. Electrical properties can be altered by changes in the densification aids.
CVD Silicon Carbide (CVDSIC). This material is formed by a chemical vapor deposition (CVD) process involving the reaction: CH3SiCl3 -> SiC + 3HCl. The reaction is carried out under a H2 atmosphere with the SiC being deposited onto a graphite substrate. The process results in a very high-purity material; however, only simple plates can be made. The process is very expensive because of the slow reaction times.
Chemical Vapor Composite Silicon Carbide (CVCSiC). This process starts with a proprietary graphite precursor that is machined into near-net shapes in the graphite state. The conversion process subjects the graphite part to an in situ vapor solid-state reaction to produce a polycrystalline, stoichiometrically correct SiC. This tightly controlled process allows complicated designs to be produced in a completely converted SiC part that has tight tolerance features and high purity. The conversion process shortens the normal production time and reduces costs over other methods.* Source (except where noted): Ceradyne Inc., Costa Mesa, Calif., www.ceradyne.com.
*Source: Poco Graphite, Inc., Decatur, Texas, www.poco.com.
Note: The above information is for general reference only and is not intended to represent the processes used by all SiC suppliers. Consult your supplier for specific SiC processing information. Ceradyne, Poco Graphite and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
Typical Silicon Nitride (Si3N4) Properties
Si3N4 has the strongest covalent bond properties next to silicon carbide. It is used as a high-temperature structural ceramic due to its superior heat resistance, strength and hardness. It also offers excellent wear and corrosion resistance. Various types are available (sintered, CVD, HP), and they are used for different purposes. Main applications include heat exchangers, rotors, nozzles, bearings, valves, chemical plant parts, engine components and armor.
Properties Units Test Value
Physical
Chemical FormulaSi3N4
Density, ρ g/cm3 ASTM C20 3.31 Color dark gray Crystal Structure hexagonal Mechanical
Thermal
Max. Use Temperature (in air) ºC No load cond. Thermal Shock Resistance ΔT (ºC) Quenching 750 Thermal Conductivity W/m-K @ R.T. ASTM C408 27 Coefficient of Linear
Electrical
Dielectric Constant 1 MHz @ R.T. ASTM D150 7.0 Dielectric Strength kV/mm ASTM D116 17.7 Electrical Resistivity Ωcm @ R.T ASTM D Source: Ferro-Ceramic Grinding, Inc., Wakefield, Mass., www.ferroceramic.com.
Note: Although we have no reason to doubt the accuracy of the data presented, this information is offered for comparison only. Exact properties will vary depending on the manufacturing method and part configuration, and can sometimes be tailored to meet specific requirements. Contact your component supplier for more detailed information. Ferro-Ceramic Grinding and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
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Terminology Commonly Associated with Silicon Nitride Processing
Recrystallized Bonded Silicon Nitride (RBSN). Starting raw material is silicon. Formed by the reaction: 3Si+2N2 -> Si3N4 at ºC. No sintering additives are used, and no volume change occurs during the reaction. The resulting material is generally 99% pure with about 25% porosity.
Sintered Silicon Nitride (SSN). Starting raw material is silicon nitride powder. Sintering additives such as yttrium oxide and aluminum oxide are used. Sintering takes place at about ºC, depending on the amount of additives employed and 1 atmosphere of pressure. Densities are generally in the 98% range with strengths in the 600-700 MPa range.
Sintered Reaction Bonded Silicon Nitride (SRBSN). The starting raw material is silicon. Sintering additives such as yttrium oxide and aluminum oxide are used. The firing process is done in two stages. First is the reaction bonding process: 3Si+2N2 -> Si3N4 at ºC, and then sintering at >ºC at 1 atmosphere. Properties are similar to SSN. The advantages are low-cost raw materials and lower sintering shrinkages that help in dimensional control.
Gas Pressure Sintered Silicon Nitride (GPS-SIN). Similar to SSN, except the sintering is performed at 20 to 100 atmospheres. The densities are generally over 99%, and the mechanical properties are superior. Lower amounts of sintering additives can be used.
Gas Pressure Sintered Reaction Bonded Silicon Nitride (GPS-SRBSN). A combination of SRBSN and GPS-SIN. This fabrication process offers the best combination of mechanical properties and low-cost processing.
Hot Pressed Silicon Nitride (HPSN). Silicon nitride powder is used as the starting raw material. Densification aids are generally magnesium or yttrium oxide plus aluminum oxide. Densification occurs by a simultaneous application of mechanical pressure and temperature inside a graphite die cavity. The shapes are simple plates, and low amounts of sintering aids can be used. Mechanical properties of hot pressed materials are used as the baseline against which other processes are compared.
Hot Isostatic Pressed Silicon Nitride (HIPSN). Similar to GPS-SIN, except that the pressures are higher&#; to atmospheres. The sintering aids are similar to HPSN. Ultimate mechanical properties are achieved. This is the highest-cost near-net-shape processing route.
Source: Ceradyne Inc., Costa Mesa, Calif., www.ceradyne.com.
Note: The above information is for general reference only and is not intended to represent the processes used by all Si3N4 suppliers. Consult your supplier for specific Si3N4 processing information. Ceradyne and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
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Typical Steatite L-5* Properties
This material has applications where insulating and temperature resistance are a concern. Many insulators and other standoffs are made of steatite. The cost of this material is relatively low when compared with other ceramic materials.
Properties Units Test Value
Physical
Chemical FormulaH2Mg3(SiO3)4
Density, ρ g/cm3 ASTM C20 2.71 Color buff Crystal Structure hexagonal Water Absorption % at room temperature (R.T.) ASTM C373 0.0-0.2 Hardness Mohs 7.5 Hardness Knoop (kg/mm2) Knoop 100 g - Mechanical
Thermal
Max. Use Temperature (in air) ºC No load cond. Thermal Shock Resistance ΔT (ºC) Quenching 190 Thermal Conductivity W/m-K @ R.T. ASTM C408 2.9 Coefficient of Linear
Electrical
Dielectric Constant 1 MHz @ R.T. ASTM D150 6.3 Dielectric Strength kV/mm ASTM D116 9.3 Electrical Resistivity Ωcm @ R.T ASTM D 104 Source: Ferro-Ceramic Grinding, Inc., Wakefield, Mass., www.ferroceramic.com.
Note: Although we have no reason to doubt the accuracy of the data presented, this information is offered for comparison only. Exact properties will vary depending on the manufacturing method and part configuration, and can sometimes be tailored to meet specific requirements. Contact your component supplier for more detailed information. Ferro-Ceramic Grinding and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
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Typical Titanium Diboride (TiB2) Properties
The values presented here are trend values derived for polycrystalline TiB2 specimens with a purity (mass fraction of TiB2) of at least 98%, a density of (4.5±0.1) g/cm3 , and a mean grain size of (9±1) µm. Estimated combined relative standard uncertainties of the property values are listed in the last column. For example, a value of 3.0 with ur = 5% is equivalent to 3.0±0.15. A question mark (?) for ur means the uncertainty could not be determined with the available data.
Property [unit] 20°C 500°C °C °C °C °C ur [%]a Bulk Modulus [GPa] 240 234 228 24 Compressive Strength [GPa] 1.8 ? Creep Rateb [10-9 s-1] 0.005 3.1 20 Densityc [g/cm3] 4.500 4.449 4.389 4.363 4.322 4.248 0.07 Flexural Strength [MPa] 400 429 459 471 489 25 Fracture Toughness [MPa m1/2] 6.2 15 Friction Coefficientd 0.9 0.9 0.6 15 Hardnesse [GPa] 25 11 4.6 12 Lattice Parameterf a [Å] 3.029 3.039 3.052 3.057 3.066 3.082 0.03 Lattice Parameterf c [Å] 3.229 3.244 3.262 3.269 3.281 3.303 0.04 Poisson's Ratio 0.108 0.108 0.108 70 Shear Modulus [GPa] 255 248 241 5 Sound Velocity, longitudinal [km/s] 11.4 11.3 11.2 5 Sound Velocity, shear [km/s] 7.53 7.47 7.40 3 Specific Heat [J/kg-K] 616 1.5 Thermal Conductivity [W/m-K] 96 81 78.1 77.8 6 Thermal Diffusivity [cm2/s] 0.30 0.17 0.149 0.147 6 Thermal Expansiong, a axis [10-6K-1] 6.4 7.0 7.7 7.9 8.3 8.9 7 Thermal Expansiong, c axis [10-6K-1] 9.2 9.8 10.4 10.6 11.0 11.6 5 Thermal Expansionh, average [10-6K-1] 7.4 7.9 8.6 8.8 9.2 9.8 6 Wear Coefficientd [10-3] 1.7 24 Weibull Modulus 11i ?
a) Estimated combined relative standard uncertainty expressed as a percentage; b) Flexure creep rate at 100 MPa for density = 4.29 g/cm3, grain size = 18 µm; c) Single crystal density; d) Density = 4.32 g/cm3, grain size = 2 µm, vslide/Pload = 0.2 m s-1 MPa-1; e) Vickers indentation, load = 5 N; f) Single crystal, hexagonal unit cell; g) Single crystal, for cumulative expansion from 293 K (20ºC), CTE = (1/x293)(x-x293)/(T/K - 293), x = a or c; h) Bulk average, for cumulative expansion from 20ºC; i) Three values have been reported in the literature: 8, 11 and 29.
Source: NIST, www.ceramics.nist.gov/srd/summary/scdtib2.htm.
Note: The data presented here were derived from reported values for a narrowly defined material specification. Using trend analysis, property relations, and interpolation methods, the self-consistent trend values for the properties of polycrystalline TiB2 were determined for a mass fraction of TiB2 of at least 98%, a density of (4.5±0.1) g/cm3, and a mean grain size of (9±1) µm. Ceramic Industry disclaims any and all liability from error, omissions or inaccuracies in the above chart.
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Typical Tungsten Carbide (WC) Properties
Tungsten carbide is generally made with high percentages of either cobalt or nickel as a second, metallic phase. These ceramic metals, or &#;cermets,&#; have wide use as cutting tools and other metals-forming tools. Pure tungsten carbide can be made as an advanced technical ceramic using a high-temperature hot isostatic pressing process. This material has very high hardness and wear resistance, and is used for abrasive water jet nozzles; however, its weight limits its use in many applications.*
Physical
Chemical FormulaWC
Density, ρ g/cm3 13.0-15.3 Color metallic gray* Crystal Structure ng Water Absorption % at room temperature (R.T.) ng HardnessVickers @ R.T. (GPa)
ng Hardness Knoop (kg/mm2) -* Mechanical
Thermal
Max. Use Temperature (in air) ºC ng Thermal Shock Resistance ΔT (ºC) ng Thermal Conductivity W/m-K @ R.T. 71-121 Coefficient of Linear
Electrical
Dielectric Constant 1 MHz @ R.T. ng Dielectric Strength kV/mm ng Electrical Resistivity Ωcm @ R.T ng Source: NIST, www.ceramics.nist.gov/srd/scd/Z.htm#M1P1.
Note: Typical values usually are representative of trends of values commonly found for a general class of B4C materials and are not necessarily the best or most appropriate values for any particular material. Exact properties will vary depending on the manufacturing method and part configuration, and can sometimes be tailored to meet specific requirements. Contact your component supplier for more detailed information. Ceramic Industry disclaims any and all liability from error, omissions or inaccuracies in the above chart.
* = information added by the editors; ng = not given in the original source
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Typical Zirconia (ZrO2) Properties
Zirconia ceramics have a martensite-type transformation mechanism of stress induction, which provides the ability to absorb great amounts of stress relative to other ceramic materials. It exhibits the highest mechanical strength and toughness at room temperature. Zirconia has excellent wear, chemical and corrosion resistance, and low thermal conductivity. Common applications include extrusion dies, wire and pipe extension, guide and other wear rollers, pressure valves, and bearing materials.
Properties Units Test Value
Physical
Chemical FormulaZrO2
Density, ρ g/cm3 ASTM C20 6.04 Color white Crystal Structure tetragonal Water Absorption % at room temperature (R.T.) ASTM C373 0.0 HardnessMohs
6.5
Hardness Knoop (kg/mm2) Knoop 100 g Mechanical
Thermal
Max. Use Temperature (in air) ºC No load cond. 500 Thermal Shock Resistance ΔT (ºC) Quenching 280-360 Thermal Conductivity W/m-K @ R.T. ASTM C408 2.7 Coefficient of Linear
Electrical
Dielectric Constant 1 MHz @ R.T. ASTM D150 26 @ 100kHz Dielectric Strength kV/mm ASTM D116 9.0 Electrical Resistivity Ωcm @ R.T ASTM D >104 Source: Ferro-Ceramic Grinding, Inc., Wakefield, Mass., www.ferroceramic.com.
Note: Although we have no reason to doubt the accuracy of the data presented, this information is offered for comparison only. Exact properties will vary depending on the manufacturing method and part configuration, and can sometimes be tailored to meet specific requirements. Contact your component supplier for more detailed information. Ferro-Ceramic Grinding and Ceramic Industry disclaim any and all liability from error, omissions or inaccuracies in the above chart.
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Advanced ceramic materials are a type of advanced materials, called engineering ceramics or technical ceramics. Due to their excellent mechanical properties, thermal stability, corrosion resistance and electrical insulation properties, they are widely used in high-tech fields and harsh environments.
There are many kinds of advanced ceramic materials, each of which has unique properties and characteristics suitable for specific applications. Therefore, choosing the right ceramic material is very important for the application.
For more information, please visit custom ceramic components.