B4C
B4C (boron carbide) is a covalent carbide ceramic covered by ASTM C750 and GB/T 33529, supplied hot-pressed (HP), pressureless-sintered (PS), reaction-bonded (RB) or as a CVD coating.
Reference datasheet — B4C is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the HP condition
B4C tempers and conditions
B4C is supplied in 3 conditions, soft to hard. HP is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Reaction bonded (silicon infiltrated) boron carbide, 8–20 % free Si | Pick silicon-infiltrated near-net shapes for large-area armour panels at the lowest cost; the 8–20 % free silicon lowers hardness and usable service temperature. | 2,400 HV | 55 W/m·K | |||
Pressureless sintered B4C | Choose pressureless sintering with C/SiC aids for complex shapes and large parts below hot-pressing cost, accepting slightly higher porosity and marginally lower strength and hardness. | 2,800 HV | 30 W/m·K | |||
HPDefault Hot pressed (pressure sintered) B4C, >99 % TD | Default when density, hardness and ballistic performance must be highest: pressure sintered to >99 % of theoretical density for armour plate, blast nozzles and neutron-absorbing elements. | 3,000 HV | 35 W/m·K |
Supply forms, finishes and certifications
Ways B4C is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
CVD | CVD/PBC | Coating |
What is B4C?
B4C (boron carbide) is a covalent carbide ceramic covered by ASTM C750 and GB/T 33529, supplied hot-pressed (HP), pressureless-sintered (PS), reaction-bonded (RB) or as a CVD coating. Engineers choose it for very high hardness at low mass — 2.51 g/cm³ density with a 450 GPa elastic modulus — and for neutron absorption from its boron content; usual forms are pressed tiles, nozzle bodies, shielding plates and control-rod components. Oxidation limits continuous service to about 800 °C, thermal conductivity is 35 W/m·K, and the material is brittle with a machinability score of 3. SiC is the lower-cost substitute where ballistic weight is not critical. B4C has a density of 2.51 g/cm³ (0.0907 lb/in³), lighter than 82% of ceramic grades. It melts at 2,450°C (4,442 °F). B4C has a tensile strength of 300 MPa (43.5 ksi), stronger than 68% of ceramic grades. The elastic modulus is 450 GPa (65.3 Msi).
What is B4C used for?
- body armor plates
- sandblasting nozzles
- neutron shielding
- wear-resistant components
Advantages
- Lightweight — 2.51 g/cm³ (0.0907 lb/in³), better than 82% of ceramic grades
- Good corrosion resistance — 90/100, better than 81% of ceramic grades
B4C properties
Typical room-temperature values for B4C-HP; bars are the position among ceramic grades.
Physical3
B4C has a density of 2.51 g/cm³ (0.0907 lb/in³), lighter than 82% of ceramic grades. It melts at 2,450°C (4,442 °F).
Mechanical12
B4C has a tensile strength of 300 MPa (43.5 ksi), stronger than 68% of ceramic grades. The elastic modulus is 450 GPa (65.3 Msi).
Thermal5
B4C is rated for continuous service to 800°C (1,472 °F). It conducts heat at 35 W/m·K (20.2 BTU/hr·ft·°F), better than 65% of ceramic grades. Thermal expansion is 4.5 µm/m·K (2.5 µin/in·°F).
Electrical2
B4C has an electrical resistivity of 0.05 Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (90/100), better than 81% of ceramic grades.
Sustainability4
Producing a kilogram of B4C takes about 260 MJ of energy and emits 22 kg of CO₂ — more than 69% of ceramic grades. Typical recycled content is 0%.
Manufacturability3
B4C's machinability is not recommended (3/100, worse than 95% of ceramic grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the ceramic family
Yield strength against density for every ceramic grade FabDigit runs. B4C is highlighted; hover a dot for its name, or open the interactive family chart.
Working with B4C
Is B4C easy to machine?
After sintering only diamond grinding, ultrasonic machining or laser processing are effective; wire EDM can be used where conductivity is sufficient. Green machining before sintering is the most economical route to complex geometry.
Can B4C be welded?
Not fusion weldable; join to metals by active brazing (Ti-bearing Ag-Cu-Ti fillers), diffusion bonding, or mechanical/adhesive clamping. Watch for reaction with Fe and Ni at high temperature.
Can B4C be formed, bent or molded?
Shaped from powder by dry pressing or isostatic pressing plus pressureless sintering above 2200 °C, hot pressing at 2100 °C/30 MPa, or silicon-infiltrated reaction bonding. Complex shapes are best made by the RB route.
B4C chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Bstoichiometric B4C is 78.3 wt% B; 10B abundance ~19.9% | 76 – 79.5 | 78.3 |
| free Cfree carbon | ≤ 1.5 | 0.6 |
| B2O3surface oxide | ≤ 0.5 | 0.2 |
| Fe | ≤ 0.3 | 0.1 |
| Sifree Si up to 8-20% in reaction-bonded grades | ≤ 0.3 | 0.1 |
| Ccombined carbon; free carbon usually <1.5% | ≥ 20 (balance) |
What surface finishes work on B4C?
Diamond lapping and polishing reach Ra < 0.05 µm. Armor parts are normally bonded to UHMWPE or aramid backing; electroplating and anodizing do not apply.
Equivalent designations
Standards and trade names that resolve to B4C in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- C750GB/T 33529
How much does B4C cost?
B4C is a high-cost ceramic ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
B4C — frequently asked
What is B4C used for?
B4C is typically used for body armor plates, sandblasting nozzles, neutron shielding and wear-resistant components. In short: hardest common structural ceramic; lowest-density armor ceramic; neutron-absorbing boron content.
What is the tensile strength of B4C?
B4C has a typical tensile strength of 300 MPa (43.5 ksi) — stronger than 68% of ceramic grades. Strength varies by condition: see the 3 listed tempers.
Is B4C easy to machine?
Not especially — machinability is rated not recommended (3/100, worse than 95% of ceramic grades). After sintering only diamond grinding, ultrasonic machining or laser processing are effective; wire EDM can be used where conductivity is sufficient. Green machining before sintering is the most economical route to complex geometry.
Can B4C be welded?
Not fusion weldable; join to metals by active brazing (Ti-bearing Ag-Cu-Ti fillers), diffusion bonding, or mechanical/adhesive clamping. Watch for reaction with Fe and Ni at high temperature.
What surface finishes work on B4C?
Diamond lapping and polishing reach Ra < 0.05 µm. Armor parts are normally bonded to UHMWPE or aramid backing; electroplating and anodizing do not apply.
Can B4C be formed, bent or molded?
Shaped from powder by dry pressing or isostatic pressing plus pressureless sintering above 2200 °C, hot pressing at 2100 °C/30 MPa, or silicon-infiltrated reaction bonding. Complex shapes are best made by the RB route.
What is the maximum service temperature of B4C?
B4C is rated for continuous use to about 800°C (1,472 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does B4C cost?
B4C is a high-cost ceramic ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM C750 — Nuclear-Grade Boron Carbide Powder — ASTM International (2015)
- ASM Engineered Materials Handbook Vol.4: Ceramics and Glasses — ASM International (1991)
- Boron Carbide (B4C) Technical Data — CoorsTek (2023)
- Hexoloy / Norbide boron carbide product data — Saint-Gobain Ceramics (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.