Solid Lubricant Additives

hBN Hexagonal Boron Nitride Lubricant Additive — White Graphite

Hexagonal Boron Nitride (hBN) solid lubricant additives for high-temperature grease, food-grade lubricants, and electrically insulating applications. White, inert, chemically stable, and suitable for demanding industrial formulations.

  • COF 0.01–0.12 — chemically inert solid lubricant
  • Stable to 900°C in air and 1,400°C in vacuum
  • Electrically insulating — unique among solid lubricants

What Is Hexagonal Boron Nitride (hBN)?

Hexagonal Boron Nitride (hBN, CAS 10043-11-5) is a white crystalline solid often called “white graphite” because of its structural similarity to graphite. Alternating boron and nitrogen atoms form hexagonal layers that can slide against each other under shear.

Unlike graphite, hBN is electrically insulating, chemically inert, and white in color. These properties open application areas where MoS₂, WS₂, or graphite may be unsuitable because of conductivity, color, oxidation behavior, or chemical compatibility requirements.

hBN maintains its structure and lubrication properties at temperatures up to 900°C in air and 1,400°C in vacuum, making it useful for high-temperature metal forming, sintering operations, ceramic processing, and electrically sensitive systems.

Powderful Solutions supplies hBN powder in four particle sizes optimized for different lubricant formulation requirements:

Solidex B004 — D50 = 0.4 μm

Sub-micron hBN for oil and grease systems. Designed for thin-film EHD contacts, food-grade lubricants, and electrically insulating applications.

Solidex BB025 — D50 = 0.25 μm

Ultra-fine hBN for precision tribological contacts and polymer composites requiring the smallest available particle size.

Solidex B050 — D50 = 0.5 μm

General-purpose hBN powder for grease formulation, metalworking compounds, and ceramic processing applications.

Solidex B250 — D50 = 2.5 μm

Larger-particle hBN for forging compounds, release agents, and sintering aids where coarser particle size improves surface coverage.

hBN Performance Characteristics

High-Temperature Lubrication

hBN can maintain a stable lubricant film at temperatures where MoS₂, graphite, and organic additive systems may lose performance.

Electrical Insulation

hBN is electrically insulating, making it useful for bearings, motors, electrical equipment, and sliding contacts where conductive additives would create risk.

Chemical Inertness

hBN resists many aggressive acids, alkalis, and reactive media, supporting compatibility in chemical, semiconductor, and pharmaceutical manufacturing environments.

White / Non-Staining Appearance

hBN does not discolor white or light-colored lubricant products, making it relevant for food-grade, cosmetic, pharmaceutical, and clean industrial applications.

Friction Reduction

COF 0.01–0.12 depending on particle size, treat rate, contact conditions, and carrier system. Effective in high-temperature, insulating, or chemically aggressive contacts.

Food-Grade Compatibility

hBN is chemically inert and non-toxic, making it suitable for lubricant formulations where food-grade or incidental food-contact compatibility is required.

hBN vs. Other Solid Lubricants

Property hBN MoS₂ WS₂ Graphite
COF (dry) 0.01–0.12 0.05–0.10 0.03 0.10–0.20
Max temp. in air 900°C 350°C 650°C 450°C
Electrically insulating Yes No No No
Color White Black Dark grey Black
Food-grade compatible Yes Limited Limited No
Chemical resistance Excellent Limited Good Good
The white, electrically insulating, chemically inert solid lubricant. When conductivity, color, or chemical reactivity rules out MoS₂, WS₂, or graphite, hBN provides a differentiated option for food-grade, high-temperature, electrical, and clean industrial applications.

hBN Products from Powderful Solutions

Solidex B004 — hBN Dry Powder
CAS 10043-11-5 | D50 = 0.4 μm | Hexagonal crystal
D50: 0.4 μm Crystal: Hexagonal Form: Dry Powder Packs: 1–25 kg

Sub-micron hBN powder optimized for oil and grease carrier systems. Suitable for high-temperature bearing greases, food-grade lubricants, and electrically insulating applications.

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Solidex BB025 — hBN Dry Powder
CAS 10043-11-5 | D50 = 0.25 μm | Hexagonal crystal
D50: 0.25 μm Crystal: Hexagonal Form: Dry Powder Packs: 1–25 kg

Ultra-fine hBN for precision tribological applications requiring the smallest particle size for thin-film EHD contacts and polymer composite blending.

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Solidex B050 — hBN Dry Powder
CAS 10043-11-5 | D50 = 0.5 μm | Hexagonal crystal
D50: 0.5 μm Crystal: Hexagonal Form: Dry Powder Packs: 1–25 kg

Mid-range particle size hBN for general-purpose grease formulation, metalworking compounds, and ceramic processing applications.

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Solidex B250 — hBN Dry Powder
CAS 10043-11-5 | D50 = 2.5 μm | Hexagonal crystal
D50: 2.5 μm Crystal: Hexagonal Form: Dry Powder Packs: 1–25 kg

Larger-particle hBN for high-temperature forging compounds, release agents, and sintering aids where coarser particle size improves surface coverage on metal surfaces.

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hBN Lubricant Additive Applications

High-Temperature Greases

hBN can be used in high-temperature base greases for oven conveyor bearings, kiln car bearings, and furnace equipment operating where conventional additives may decompose.

Food-Grade Lubricants

hBN is useful in food processing equipment greases, conveyor chain lubricants, and incidental food-contact applications where white, inert, non-toxic additives are preferred.

Electrical Equipment

Bearings and sliding contacts in electric motors, generators, and switchgear where conductive MoS₂ or graphite could cause insulation breakdown or short circuits.

High-Temperature Metal Forming

Forging lubricants, hot-pressing compounds, and sintering aids for steel, titanium, and aluminum alloy manufacturing at elevated process temperatures.

Ceramics & Semiconductor

Release agent and lubricant in ceramic pressing, semiconductor wafer processing, and refractory manufacturing where chemical inertness helps reduce contamination risk.

Composite & Polymer Systems

Dry lubricant additive in PTFE, nylon, PEEK, and other engineering polymer composites for bearing and bushing applications requiring low friction without discoloration.

Frequently Asked Questions

What is hBN used for in lubricant formulations?
Hexagonal boron nitride (hBN) is used as a high-temperature solid lubricant additive in greases, dry film coatings, and polymer composites. It is particularly valued for applications requiring electrical insulation, food-grade compatibility, chemical inertness, or operation above 350°C where MoS₂ and WS₂ may be unsuitable. Common applications include oven conveyor greases, food processing equipment, electric motor bearings, and high-temperature metal forming compounds.
Why is hBN called white graphite?
hBN has a hexagonal layered crystal structure similar to graphite, with boron and nitrogen atoms alternating in place of carbon. Like graphite, weak van der Waals forces between planes allow easy shear and low friction. Unlike graphite, hBN is white, electrically insulating, and chemically inert, making it suitable for applications where graphite’s electrical conductivity or black color is unacceptable.
Is hBN food-safe for use in food-grade lubricants?
hBN is chemically inert, non-toxic, and compatible with food-grade lubricant formulation requirements. When blended into approved base oils and thickeners, hBN-containing greases may be used in incidental food-contact lubricant applications. Powderful Solutions can provide purity and compliance documentation for food-grade applications.
What particle size hBN is best for grease additives?
Sub-micron hBN (D50 ≤ 0.5 μm) provides a strong balance of lubrication effectiveness and dispersion stability in oil and grease carriers. Powderful Solutions offers Solidex BB025 (0.25 μm), Solidex B004 (0.4 μm), and Solidex B050 (0.5 μm) for lubricant formulation. Solidex B250 (2.5 μm) is suited to forging compounds, release agents, and sintering aids where coarser particles improve surface coverage.
What is the recommended treat rate for hBN in high-temperature grease?
For high-temperature bearing greases such as oven conveyors, kiln cars, and furnace equipment, 3–10 wt% hBN powder in a PFPE, silicone, or calcium sulfonate complex base is typical. For metalworking and forging compounds, higher loadings of 10–30 wt% are common. Final treat rate should be validated in the specific lubricant matrix and operating environment.

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