Introduction
Electrical insulation and thermal conductivity are two of the most sought-after qualities most modern manufacturers look out for. No one wants a device or equipment that overheats or causes electrocution during usage. This is exactly why boron nitride ceramics seem to appear in almost any conversation involving ceramic parts. Not only that, it also has some other exciting properties. In today’s article, you’ll be shown the key properties and features of boron nitride ceramics, and get an answer to the very popular question - what is boron nitride used for? You’ll also be exposed to the various boron nitride uses available today and their product categories.
Boron Nitride Based Ceramics
Boron nitride ceramic materials are extremely hard ceramic materials made from the industrial combination of boron and nitride. Boron nitride (BN) in itself is a covalently bonded, powdered crystalline compound available in various forms that can perform efficiently well even under unfavorable or high-stress conditions. This is due to its rare ability to excellently conduct heat and resist electricity, almost the same way aluminum nitride ceramics does. So, think of boron nitride ceramics as very machinable super strong ceramic materials you need in most production projects.
After all, not many ceramic materials can boast of electrical insulation, thermal conductivity, and stability as boron nitride ceramic parts. Considering how the hexagonal boron nitride (Hbn) form even appears whitish at times, you might mistake it for white graphite because it doubles as an excellent lubricant and strong insulator material. The multidimensional nature of boron nitride ceramics makes it cut across many industrial sectors. It serves as a high-strength electrical insulator in high-power electronics devices, machine spare parts, rotors, engines, and ceramic feedthroughs.
Biomedical engineers, mechanical engineers, and aerospace technologists all use the various forms of BN ceramics to suit their high precision demands. The nearly unmatched strength and flexibility make it a stand-out material that can help you produce LED lights, refractories used in furnace settings, semiconductor components, lab crucibles, and heat sinks.
General Properties of Boron Nitride Ceramics
Boron nitride ceramics possess a wide range of properties that make them easy to use, and also very essential to virtually any industry. Some of them are:
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It has an impressive ability to withstand very high temperatures and high-stress conditions.
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It’s not easily dissolved by water, acids, or strong chemicals.
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It’s a good semiconductor material with a wide band gap of 10.7 eV.
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Its thermal coefficient of expansion is around 2.7.
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It possesses excellent resistance to wear and tear.
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It has a bulk modulus of about 400 GPa.
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It has a melting point that is above 2,800°C.
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It possesses a strong heat capacity of 19.5 J/K.mol.
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It has a molar mass of 24.82 g/mol.
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It has a high thermal conductivity of 740 W/m.K.
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It has a very high compressive strength and stability that ranks it second only to silicon carbide and aluminum nitride ceramics.
Product Categories of Boron Nitride Ceramics
Boron nitride is known to be available in three major forms and product categories - Hexagonal, Wurtzite, and Cubic boron nitride. Although the same boron nitride, there are some slight differences between these forms which has led to the several product categories of boron nitride you’ll find in today’s market. Here’s a quick look at them!
Hexagonal Boron Nitride (Hbn)
This is considered one of the best and most common forms of boron nitride ceramics due to its excellent stability, insulating, and lubricating power. It has a layered crystalline structure that can help you produce strong li-ion batteries, processors, and capacitors for the panel of some electronic devices. It’s a bit whitish in appearance and very slippery. You can get it produced industrially by the chemical combination of Nitrogen/Ammonia (NH3) and boric acid under high temperatures.
Some of the key features of hexagonal boron nitride are:
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It has a layered structure similar to that of Graphite.
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It’s very hard although not as compared to cubic or wurtzite boron nitride.
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It possesses a density of 2.1 g/cm³.
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It has a very high thermal conductivity.
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It’s used mainly as an electrical insulator or industrially as a solid lubricant.
Cubic Boron Nitride (CBN)
This is one of the hardest ceramic materials you can ever find globally, and it’s rated next to Diamond. It’s polycrystalline and commonly called Borazon. It sometimes appears black or gold and has a structure that is very similar to a diamond. With that, it can comfortably withstand high mechanical stress and extreme temperatures. It hardly reacts with other chemicals or gets rusted, making many industries use it for the manufacturing of cutting/grinding steel wheels for machines.
You can produce Cbn under high temperatures by sintering hexagonal boron nitride in high-pressure conditions. Some of the key features of cubic boron nitride are:
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It has a cubic structure similar to a diamond.
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It has a very high hardness second only to Diamond and wurtzite boron nitride.
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It has a maximum density of 3.48g/cm³.
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It possesses a very high level of thermal conductivity and stability.
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It can be used majorly as an abrasive or cutting tool.
Wurtzite Boron Nitride (Wbn)
The wurtzite form of boron nitride is not so common. It’s whitish in color and the hardest of all three product categories of boron nitride. Fun fact is that you don’t necessarily need very high temperatures to produce it industrially. It can serve as a very key component of optical instruments and semiconductors due to its wide band gap and optical transparency.
Some of the key features of wurtzite boron nitride are:
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It’s very efficient at heat dissipation and thermal conductivity.
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It has an extremely hard hexagonal crystal structure similar to a diamond.
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It’s an excellent electrical insulator like aluminum nitride ceramics.
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You can use ceramic parts in thermal management and the production of high-power electronics.
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It possesses a very good optical transparency that makes it suitable for other advanced manufacturing options.
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It’s long-lasting, stable, and can withstand mechanical stress.
Uses of Boron Nitride Ceramics
If you’ve ever wondered - “what is boron nitride used for?” This section will help you with answers. The fact is, boron nitride uses span across so many sectors. Here are some of them:
Electrical Industry
Boron nitride uses in the electrical industry are:
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Production of efficient electrical insulators for machine parts, seal rings, and hermetic/ceramic feedthroughs.
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Boron nitride ceramics can help produce semiconductor components, due to its light weight and impressive strength.
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Nanotechnology now produces faster and more reliable batteries for electric vehicles, microprocessors, and heat sinks with boron nitride.
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Electrical engineers use boron nitride ceramics as a major component in the production of high-power electronics, LED lights, electronic panels for TV sets, computers, MOSFETs, and many other similar products.
Metallurgical industry
The metallurgical industry is not left out when it comes to boron nitride uses. Some of these uses are:
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The production of refractory materials that can withstand heat and high temperatures.
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Boron nitride helps in producing efficient and long-lasting ceramic parts for kiln linings.
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The production of rods and furnace materials that are extremely resistant to wear and tear.
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Boron nitride ceramics is a major component in the production of cutting and grinding tools/wheels in machine parts.
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Boron nitride is used to produce thermally stable and strong metal casings.
Automotive and Aerospace Industries
Boron nitride ceramics are also useful in these important industries. Some of the ways you can use them here are:
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The production of vehicle parts that do not wear out easily.
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The production of aerospace or car engines that do not overheat due to effective heat dissipation.
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The production of long-lasting machine parts saves you the cost of production.
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The production of aerospace parts and equipment because of their lightweight.
Other uses of boron nitride ceramics in several other sectors include:
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The production of enamels used in dental facilities due to their ability to manage wear and tear.
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Production of laboratory crucibles, machine bearings, and rotors.
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You can even use boron nitride as a good ceramic feedthrough for hermetic systems/vacuums.
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Boron nitride is an essential component that industries use in manufacturing ceramic fillers, nanotubes, li-ion batteries, and solid lubricants.
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It’s a good material you can use in optical instruments, high-purity cosmetics, and glass production.
Frequently Asked Questions
What differentiates Hexagonal boron nitride (Hbn) from Graphite?
Even though they may look alike, graphite tends to be more of a conductor or semiconductor material while hexagonal boron nitride is an electrical insulator.
Why are boron nitride ceramics special to many manufacturers?
It’s special not only because it’s very affordable but also extremely hard (second only to Diamond), lightweight, thermally stable, and insulates electricity efficiently.
Does boron nitride have any defects?
Yes, it does and some of these defects are impurities caused by the production (growth) process, point defect antisites, and self-interstitials.
Conclusion
Boron nitride ceramics are already becoming a useful innovative outlet for new energy and global technological advancements today. Considering the perfect blend of properties and all-round usage in many sectors like the electrical, metallurgical, aerospace, and automotive industries, we can safely say, it’s a fast-rising ceramic material set to take over many industrial productions. Little wonder, it’s garnering global sales of over $130 million yearly. That said, you’re surely on the right path if you’re looking to purchase or invest in any of its product categories. You can contact GGSCeramics to check out some of the best BN products. Don’t snooze on this! Now is a perfect time!