What are metal borides?
Metal borides can be formed when a metal bonds with boron at high temperatures. The result is a compound with properties that exceed those of the metal or boron on its own. Depending on the metal used, the compound can be extremely hard, electrically conductive, chemically stable at high temperatures or capable of absorbing infrared radiation.
The two main groups of metal borides
The most commercially important metal borides fall into two groups. Rare earth metal borides, such as lanthanum hexaboride (LaB₆), are known for their strong infrared absorption and electron emission properties. Transition metal borides, such as titanium diboride (TiB2), are valued for their extreme hardness and resistance to wear and high temperatures.
Partners in Chemicals supplies both groups, as powders, nanoparticles and as part of coating formulations.
A new approach to metal boride coatings
Traditional coating methods such as CVD, PVD and sputtering require temperatures between 800 and 1800°C and expensive vacuum equipment. This limits the range of substrates that can be coated and makes the process costly and energy-intensive.
Partners in Chemicals offers a patented ink platform based on metal boride nanocrystals of 5 to 20 nm. This ink can be applied directly onto a substrate via inkjet printing, spray coating, blade coating or dip coating. Drying takes place at temperatures below 90°C, which means the coating works on flexible and heat-sensitive substrates as well.
The ink is stable for several months and can be formulated at concentrations up to 50 mg/mL. It can be used with a range of solvents and substrates, without changing existing printing or coating equipment. Curious about the chemistry behind our products? Curious about the chemistry behind our products? Read more on the Our Chemistry page.
Applications of metal boride coatings
Lanthanum hexaboride (LaB6) is one of the strongest near-infrared (NIR) absorbers in the 900-C1400 nm wavelength range known to men.. This is the part of the solar spectrum that causes heat build-up inside buildings and vehicles. By incorporating LaB6 nanoparticles into window films, architectural glazing or automotive glass, the amount of heat passing through is significantly reduced.
Compared to alternatives such as ITO or ATO, LaB6 works at much lower concentrations. A small quantity is enough to achieve a clear reduction in infrared transmission. LaB6 carries no hazard classification and requires no special handling precautions. SrB6 is another boride with infrared absorbing properties and is used in similar applications.
Titanium diboride (TiB2) is one of the hardest materials available, with a Vickers hardness of around 3000 HV (29.4 GPa). It remains stable at temperatures well above 1000°C. TiB2 coatings protect surfaces exposed to heavy wear, such as cutting tools, pump components, dies and moulds. Applying a boride coating to these surfaces reduces wear and extends the working life of the component.
CaB6 adds to this with a hardness of around 27 GPa and is used in applications where both hardness and chemical stability are required.
CeB6 has high electrical conductivity and remains stable at extreme temperatures. It is used as a cathode material in electron guns and scanning electron microscopes, where high current density and beam stability are required. Ni3B is a semiconducting material with applications in electronics and energy solutions.
LaB6 and SrB6 are used in solar energy applications for their infrared absorbing and UV coating properties. By filtering specific parts of the solar spectrum, these coatings can improve the energy output of solar panels or reduce heat load in building-integrated photovoltaics.
The metal borides in this technology
The ink platform is built around a selection of metal boride nanocrystals, each chosen for what it contributes to the final coating. Below is an overview of the borides used and their role within the formulation.
LaB₆ is the primary infrared absorber in the formulation. It absorbs NIR radiation in the 900–1400 nm range and has a hardness of around 20 GPa. It is used in coatings for thermal shielding and optical applications.
CeB6 brings high electrical conductivity to the formulation. It is a ceramic material that remains stable at extreme temperatures, with a hardness of around 20 GPa. It is used in conductive coatings and cathode applications.
CaB6 is the hardest boride in this formulation, reaching around 27 GPa. It has high electrical conductivity and shows superconducting behaviour at low temperatures. It also behaves as a weak ferromagnet at high temperatures.
SrB6 has semi-metallic behaviour and functions as an infrared absorber alongside LaB₆. It is a ceramic material that remains stable at extreme temperatures, with a hardness of around 28 GPa.
TiB2 is the primary hard coating material in the MB2 group. With a Vickers hardness of around 3000 HV (29.4 GPa), it provides wear resistance and mechanical protection in the final coating layer.
Ni3B is a semiconducting material with a hardness of around 11 GPa. It is used in the formulation for electronics and energy applications, where semiconducting behaviour in the coating is required.
Properties of metal borides
Mechanical properties
Metal borides are among the hardest inorganic materials known. Titanium diboride (TiB2) reaches a Vickers hardness of around 3000 HV (29.4 GPa). Lanthanum hexaboride (LaB₆) has a hardness of around 20 GPa, CeB6 around 20 GPa, SrB6 around 28 GPa and CaB6 around 27 GPa. Most metal borides also have high melting points. TiB2 melts at 3225°C and LaB₆ at 2210°C. This makes them reliable in applications where both surface durability and thermal resistance matter.
Chemical stability at high temperatures
Metal borides do not break down easily under heat and resist oxidation up to high temperatures. TiB2 remains stable in air up to around 1000°C. They are also resistant to most acids and alkalis under normal conditions. This makes boride coatings reliable in environments where other coating materials would degrade quickly.
The advantage of smaller particles
Smaller particles have a larger surface area relative to their volume. In practice, this means that nanoparticles of LaB₆ absorb infrared radiation more uniformly and at lower loadings than coarser powders. For hard coatings, finer TiB2 or ZrB2 particles produce denser, more homogeneous layers with fewer defects. This improves both hardness and adhesion. Nanoparticles also open up processing routes that are not possible with larger powders, such as inkjet printing or blade coating at low temperatures. The patented ink platform developed around metal boride nanocrystals (5–20 nm) is a good example of what becomes possible at the nanoscale.
Safety and handling
Metal borides do not carry hazard classifications under standard conditions. LaB₆, TiB2 and the other borides in this formulation are completely safe and environmentally benign.. No hazard symbols apply under normal storage and handling conditions. Standard industrial hygiene practices apply: avoid prolonged inhalation of fine dust and use gloves when handling powders. A Safety Data Sheet (SDS) is available upon request.
Frequently asked questions
Metal borides are inorganic compounds formed by combining a metal with boron at high temperatures. The resulting compound has properties that neither the metal nor boron has on its own, such as extreme hardness, high electrical conductivity or the ability to absorb infrared radiation.
LaB₆ is primarily used as an infrared absorber. It absorbs near-infrared radiation in the 900–1400 nm range, which is the part of the solar spectrum responsible for heat build-up. It is used in window films, architectural glazing and automotive glass to reduce heat transmission. LaB₆ is also used as a cathode material in electron guns and scanning electron microscopes.
The ink platform is based on metal boride nanocrystals of 5 to 20 nm. These nanocrystals are formulated into a stable ink that can be applied via inkjet printing, spray coating, blade coating or dip coating. The ink dries at temperatures below 90°C, which means it can be applied to flexible and heat-sensitive substrates without damaging them.
Conventional methods such as CVD, PVD and sputtering require temperatures between 800 and 1800°C and expensive vacuum equipment. This limits the substrates that can be used and makes the process costly. The metal boride ink platform works at temperatures below 90°C, requires no vacuum equipment and is compatible with existing industrial printing lines.
Metal borides do not carry hazard classifications under standard conditions. LaB₆, TiB2 and the other borides in this formulation are not listed as toxic, carcinogenic or environmentally hazardous. Standard industrial hygiene practices apply, such as avoiding prolonged inhalation of fine dust and wearing gloves when handling powders.
Nanoparticles have a much larger surface area relative to their volume. This means they absorb infrared radiation more uniformly, produce denser coating layers and perform better at lower concentrations. Working at the nanoscale also makes it possible to apply the material via inkjet printing and blade coating, which is not possible with larger particles.
The ink platform works on a wide range of substrates, including flexible and heat-sensitive materials. Because drying takes place below 90°C, substrates that would be damaged by conventional high-temperature coating processes can be used. The formulation can be tuned for different solvents and substrate types.
Metal boride coatings are used in solar energy, architectural glazing, automotive glass, electronics, industrial tooling and semiconductor manufacturing. LaB₆ and SrB₆ are used for infrared absorption and heat shielding. TiB2 and CaB6 are used for wear-resistant and ultrahard coatings. CeB₆ and Ni3B are used in conductive and semiconducting applications.
Disclaimer
The information provided on this page is based on current knowledge and intended for general guidance. Metal boride formulations should be tested in the specific application to confirm suitability, performance and compliance with regulatory requirements. While every effort has been made to ensure accuracy, Partners in Chemicals makes no representations or warranties regarding the completeness, reliability or suitability of the content. Users should verify details and consult official datasheets or regulatory guidance when making technical or industrial decisions.