Silicon Carbide (SiC) Components — Technical Ceramics Properties, Grades and Applications
SiC · 碳化矽 · LONGYI grades SCB32 / SCB316
Advanced ceramics, technical ceramics and fine ceramics are three names for the same family of engineered materials — the term changes with the region, the material does not. Within that family, silicon carbide is the stiffness-and-hardness end of the range. LONGYI Precision Technology manufactures SiC ceramic components in two production grades — SCB32 and SCB316, both 99.8% purity — machined to drawing for wafer handling arms, large vacuum chucks and stages, optical mounts, seal faces and abrasive nozzles. Both grades are produced and finished in-house in Taiwan as an OEM / ODM manufacturer, not resold.
Material at a Glance
Hardness and stiffness both at the top of the range — and it still moves heat.
Silicon carbide reaches 22–23 GPa Vickers hardness and 430–440 GPa Young's modulus, the highest of any material we produce and more than twice the stiffness of steel, with 3900 MPa compressive strength behind it. It carries that at a density of only 3.2 g/cm³, and high stiffness divided by moderate density is what specific stiffness means — a large SiC stage or handling arm deflects less and settles faster than the same part in any other ceramic. Add 50–60 W/(m·K) thermal conductivity and a low 3.7 ×10⁻⁶/°C expansion and the part also holds its geometry while the tool heats up. The honest limit is electrical: at 10⁵–10⁸ Ω·cm silicon carbide is not an insulator, and at 450–540 MPa flexural strength it is not the material for thin walls or sharp corners.
How Silicon Carbide Compares
Six properties that decide most selections. SiC leads the two stiffness-related bars outright, sits mid-range on strength, and is at the conductive end of the resistivity bar — which is the single most common reason a SiC part is specified by mistake.
Markers are spaced evenly by rank, not to linear scale. Representative grades: Silicon Carbide = SCB32 / SCB316 · Alumina = AOW37 / AOI38 · Zirconia = ZOI60 · Silicon Nitride = three production grades · Aluminum Nitride = ANG34 · Porous Ceramic = SED90 · Machinable = BN-T2300. Values from LONGYI internal property testing.
Read this before specifying SiC as an insulator
Silicon carbide is a semiconductor, not a dielectric. Volume resistivity is 10⁵ Ω·cm for SCB32 and 10⁸ Ω·cm for SCB316 — between six and eleven orders of magnitude below alumina, and falling further with temperature (10³ Ω·cm at 500 °C for both grades). If the part has to stand off a voltage, specify alumina (Al₂O₃) or aluminum nitride (AlN) instead, both at >10¹⁴ Ω·cm. This is the single most common misuse of the material.
Silicon Carbide Properties by Grade
Typical values from LONGYI internal testing. Both grades are 99.8% purity, black, and fully dense with zero water absorption.
| Property | SCB3299.8% · Black | SCB31699.8% · Black · ESD |
|---|---|---|
| Physical | ||
| Bulk Densityg/cm³ | 3.2 | 3.16 |
| Water Absorption% | 0 | 0 |
| Mechanical | ||
| Vickers Hardness HV1GPa | 22 | 23 |
| Flexural StrengthMPa | 540 | 450 |
| Compressive StrengthMPa | 3900 | 3900 |
| Young's ModulusGPa | 430 | 440 |
| Poisson's Ratio— | 0.16 | 0.17 |
| Fracture ToughnessMPa·m½ | 4 – 5 | 2 – 3 |
| Thermal | ||
| Thermal Expansion 40–400 °C×10⁻⁶/°C | 3.7 | 3.7 |
| Thermal Expansion 40–800 °C×10⁻⁶/°C | 4.4 | 4.4 |
| Thermal Conductivity 20 °CW/(m·K) | 60 | 50 |
| Specific HeatJ/(kg·K) | 700 | 700 |
| Thermal Shock Resistance°C, quenched in water | 400 | — |
| Max Use Temperature°C | 1600 | 1600 |
| Electrical | ||
| Volume Resistivity 20 °CΩ·cm | 10⁵ | 10⁸ |
| Volume Resistivity 300 °CΩ·cm | 10⁴ | 10⁴ |
| Volume Resistivity 500 °CΩ·cm | 10³ | 10³ |
| Chemical Resistance — weight loss mg/cm² | ||
| Nitric Acid60%, 90 °C, 24 h | 0.04 | ≒0.00 |
| Sulphuric Acid95%, 95 °C, 24 h | 0.01 | ≒0.00 |
| Caustic Soda30%, 80 °C, 24 h | ≒0.00 | ≒0.00 |
Values are typical for the stated grade and test condition, not guaranteed minimums. A dash (—) means the property has not been measured for that grade, not that it is zero. Dielectric strength is not quoted for silicon carbide because the material is not used as a dielectric. Final part specification is governed by the approved drawing and order confirmation.
What Each Number Actually Buys You
Which Grade Do You Need?
The stronger, more conductive grade. Higher flexural strength, higher fracture toughness and better heat spreading make it the default for load-carrying structures, seal faces and thermal duty. Its 10⁵ Ω·cm resistivity is semiconductive, so it is not the grade to put under a bare die.
- Flexural540 MPa
- Fracture Toughness4 – 5 MPa·m½
- Thermal Cond.60 W/(m·K)
- Resistivity10⁵ Ω·cm
Resistivity raised to 10⁸ Ω·cm — inside the static-dissipative window, so charge bleeds away instead of accumulating and discharging into a wafer or a die. Slightly harder and stiffer as well. The cost is mechanical: flexural strength falls to 450 MPa and fracture toughness to 2–3, so keep sections generous.
- Flexural450 MPa
- Fracture Toughness2 – 3 MPa·m½
- Thermal Cond.50 W/(m·K)
- Resistivity10⁸ Ω·cm
Both grades share the same 99.8% purity, the same 3900 MPa compressive strength, the same 1600 °C limit and the same expansion behaviour — so temperature and stiffness are not the deciding factors between them. Electrostatic behaviour is. If the part touches a wafer, a panel or a bare die, start from SCB316; see also anti-static ceramic (ATC).
Two Process Routes: SSIC and RBSIC
Silicon carbide is classified by how it is densified, and the route changes what the part can be. Both routes are available; which one suits a given part depends on size, geometry, chemistry and quantity, and is confirmed at quotation.
| Property | SSICPressureless Sintered | RBSICReaction Bonded |
|---|---|---|
| Bulk Densityg/cm³ | 3.12 | 3.06 |
| Open Porosity% | <0.2 | <0.3 |
| Flexural StrengthMPa | >380 | >350 |
| Compressive StrengthMPa | >2500 | >2500 |
| Young's ModulusGPa | 410 | 400 |
| Fracture ToughnessMPa·m½ | 4 – 5 | 2 – 3 |
| Thermal Expansion 40–400 °C×10⁻⁶/°C | 3.5 | 3.4 |
| Thermal Expansion 40–800 °C×10⁻⁶/°C | 4.4 | 4.4 |
| Specific HeatJ/(kg·K) | 700 | 700 |
| Volume Resistivity 20 °CΩ·cm | 10⁵ | 10⁸ |
| Volume Resistivity 500 °CΩ·cm | 10³ | 10³ |
| Nitric Acid60%, 90 °C, 24 h · mg/cm² | 0.04 | ≒0.00 |
| Sulphuric Acid95%, 95 °C, 24 h · mg/cm² | 0.01 | ≒0.00 |
| Caustic Soda30%, 80 °C, 24 h · mg/cm² | ≒0.00 | ≒0.00 |
SSIC is sintered without free silicon, which is why it holds the higher strength, stiffness and fracture toughness and is the safer choice in aggressive chemistry. RBSIC is infiltrated with silicon during firing, so it barely changes dimension while densifying — that is what makes large, thick or complex geometry practical at lower cost. The trade-off is the residual free silicon, which is attacked by strong alkali and by hydrofluoric acid; for those environments specify SSIC and tell us the chemistry. Thermal conductivity for both routes is 50–60 W/(m·K) as measured on our production grades above. Values are typical, not guaranteed minimums.
Where Silicon Carbide Is Used
Semiconductor & Display
- Wafer handling arms and end effectors
- Large vacuum chucks, stages and platens
- Process chamber components
- ESD-safe fixtures in SCB316
Precision & Optics
- Mirror substrates and optical mounts
- Metrology reference plates and bases
- High-acceleration motion components
- Air bearing and guideway components
Wear, Flow & High Temperature
- Mechanical seal faces and seal rings
- Sandblast and waterjet nozzles
- Heat exchanger and burner components
- Pump and valve wear parts
When Silicon Carbide Is the Wrong Choice
We would rather tell you the limits up front than have you machine a part that fails in service. Each of these is a real boundary in the data above.
At 10⁵–10⁸ Ω·cm and falling to 10³ Ω·cm at 500 °C, silicon carbide cannot stand off a voltage. For feedthroughs, standoffs, high-voltage isolation or anything specified with a dielectric strength, use alumina (Al₂O₃) or aluminum nitride (AlN), both >10¹⁴ Ω·cm.
Thin walls, slender sections, threads and sharp internal corners will chip. At 450–540 MPa flexural strength and 2–5 MPa·m½ fracture toughness, SiC has roughly half the strength of zirconia (ZrO₂) at 1000 MPa, whose 200 GPa modulus lets it flex slightly instead of cracking.
400 °C is good, but it is no longer the top of the range. Silicon nitride (Si₃N₄) survives 800–900 °C — more than twice as much — because it combines 1020 MPa strength with the lowest expansion in the range at 2.8 ×10⁻⁶/°C. For repeated quenching under mechanical load, that is the material.
50–60 W/(m·K) moves heat well for a ceramic, but a power die needs more. Aluminum nitride (AlN) reaches 220 W/(m·K) — nearly 4× higher — while keeping >10¹⁴ Ω·cm resistivity, which SiC cannot offer at any conductivity.
SiC has zero water absorption, so vacuum reaches the workpiece only through drilled holes or machined grooves — which mark thin or fragile work. Porous ceramic (PC) is itself SiC-based but carries 35–45% open porosity with 2–100 µm pores, pulling vacuum evenly across the whole working face.
Both SiC grades are rated to 1600 °C. Beyond that use alumina at 1700 °C, aluminum nitride at 2200 °C, or boron nitride (BN), which runs to 2100 °C in inert atmosphere and 1500 °C in vacuum.
If the part is a plain wear liner, a guide or a general insulator with no stiffness or heat requirement, SiC is more material than the job needs and costs more to grind. Alumina at 15.2 GPa hardness handles most of that work at a fraction of the cost.
SiC must be formed, sintered and then diamond-ground, so a prototype takes weeks. For a one-off, a design still in revision, or a part needed in days, machinable ceramic is cut directly from stock with conventional tooling — no sintering, no shrinkage, no shrink compensation.
Parts We Make in Silicon Carbide
SiC is used as the stiff structural body, the wear face or the porous base in several of our standard product lines.
From Material to Finished Part
Choosing silicon carbide is the easy half. Whether the geometry can actually be produced — and held to tolerance in a material this hard — depends on forming, sintering, diamond machining and measurement.
Advanced Ceramics Manufacturing
SiC parts start as formed green bodies and shrink during firing, and the compensation is calculated per material and per process route rather than applied as a fixed percentage. Everything after that is diamond work — grinding and lapping are the only practical way to finish a 23 GPa surface, and best achievable flatness is 0.5 µm (0.0005 mm). Where the shrinkage is absorbed and which faces actually need grinding is what decides whether a feature is economical.
See our manufacturing processAbout LONGYI Precision Technology
We are a Taiwan-based technical ceramics manufacturer, not a trading house. Forming, sintering, CNC and 5-axis machining, brazing, Mo-Mn metallization and final inspection are handled in-house, which is what makes true OEM / ODM work — build to drawing, build to sample — practical at low volume.
About LONGYI Precision TechnologyNot Sure Whether SCB32 or SCB316 Fits Your Part?
Send a drawing, a sample, or just describe the operating condition — load, temperature, media, whether the part touches a wafer. Our engineers will come back with a grade recommendation and a quotation.
Talk to Our EngineersFrequently Asked Questions
What is silicon carbide (SiC)?
Silicon carbide is a sintered ceramic of silicon and carbon used where a part has to stay hard, stiff and dimensionally stable under load, heat or abrasion — the hardest and stiffest material in the technical ceramics family, at 22–23 GPa Vickers hardness and 430–440 GPa Young's modulus. Unlike most ceramics it is a semiconductor rather than an insulator, so it is specified for structure, wear and heat, not for electrical isolation.
Is "technical ceramics" the same as "advanced ceramics"?
Yes. Advanced ceramics, technical ceramics, engineering ceramics and fine ceramics all describe the same family of engineered materials — the term follows the region rather than the material. North America and Taiwan tend to say advanced ceramics, Europe and the UK say technical ceramics (German: Technische Keramik), and Japan says fine ceramics. A silicon carbide part specified under any of those headings is the same part.
Can silicon carbide be used as an electrical insulator?
No. Volume resistivity is 10⁵ Ω·cm for SCB32 and 10⁸ Ω·cm for SCB316 at 20 °C, dropping to 10³ Ω·cm at 500 °C — many orders of magnitude below a dielectric. For insulation use alumina or aluminum nitride at >10¹⁴ Ω·cm. SCB316's 10⁸ Ω·cm is deliberately in the static-dissipative window, which is a different requirement from insulation.
What is the difference between SCB32 and SCB316?
Electrostatic behaviour, and what it costs mechanically. SCB316 sits at 10⁸ Ω·cm so accumulated charge bleeds away continuously instead of discharging into a wafer or a bare die, and it is marginally harder and stiffer. SCB32 stays at 10⁵ Ω·cm but carries 540 MPa flexural strength against 450, fracture toughness of 4–5 against 2–3, and 60 W/(m·K) against 50. Choose SCB316 when the part touches static-sensitive product; otherwise SCB32.
SSIC or RBSIC — which route should I specify?
Specify the requirement, not the route, and let us match it. SSIC contains no free silicon, so it holds the higher strength, stiffness and fracture toughness and is the safer choice in strong alkali or hydrofluoric acid. RBSIC changes dimension very little during firing, which makes large, thick or complex geometry practical at lower cost. Send the drawing with the chemistry and the size and we will tell you which route the part should take.
Silicon carbide or silicon nitride for thermal shock?
Silicon nitride, if thermal shock is the design driver: it survives an 800–900 °C quench against 400 °C for SiC, and adds 1020 MPa flexural strength and 6–7 MPa·m½ fracture toughness. Silicon carbide is the better answer when hardness, stiffness or abrasion dominate — 22–23 GPa and 430–440 GPa against 12.7–14 GPa and 270–300 GPa. Many parts are decided by which of those two lists is longer.
What tolerance and surface finish can you hold on a SiC part?
As-fired surfaces move with sintering shrinkage, so critical dimensions are reached by diamond grinding and lapping — best achievable flatness is 0.5 µm (0.0005 mm). Because SiC is the hardest material we machine, grinding time drives the price: specify tolerance only on the faces that need it. Send a drawing with the critical dimensions identified and we will quote the finishing to match.
Do you supply silicon carbide to drawing, or only standard parts?
To drawing, and to sample. Custom OEM / ODM geometry is our normal work rather than an exception — most of what we ship is specific to one customer's tool. Send a 2D drawing or a 3D model with the critical dimensions identified, together with the operating condition, and we will come back with a grade, a process route and a quotation.
Explore All LONGYI Ceramic Materials
Ten material families, all manufactured and machined in-house.
Also Known As
silicon carbide, SiC, carbide of silicon, carborundum, 碳化矽, 碳化硅, 炭化ケイ素, Siliziumkarbid, silicon carbide ceramic, sintered silicon carbide, SSIC, pressureless sintered SiC, RBSIC, reaction bonded silicon carbide, siliconized silicon carbide, black ceramic, SCB32, SCB316, ESD silicon carbide, static dissipative ceramic, technical ceramics, engineering ceramics, fine ceramics, SiC wafer handling arm, SiC end effector, SiC vacuum chuck, SiC stage, SiC mirror substrate, silicon carbide seal face, silicon carbide nozzle, precision ceramic machining, custom silicon carbide components
Silicon Carbide Parts We Produce
A cross-section of the SiC work that leaves our shop — semiconductor, pump and seal, temperature measurement, and structural sections. Each is machined to a customer drawing rather than sold from a catalogue.
Photographs show representative parts. Grade, dimensions, tolerance and surface finish are specified per drawing and confirmed at order.
LONGYI | Advanced Ceramic Manufacturer
