Boron Nitride cbn is an advanced ceramic known for its superior properties. BN chemistry has Boorstikstof bonds that give rise to different structures. Of the structures of BN one such prominent structure of interest is Cubic Boron Nitride cbn. Let us try to understand c-bn and its relative aspects.
Table of Contents
- Structure of Hexagonal Boron Nitride
- Properties of Hexagonal Boron Nitride
- Toepassingen van hexagonaal boornitride
- What is cubic Boron Nitride?
- Structure of Cubic Boron Nitride
- Eigenschappen van kubieke boornitride
- Kubieke boornitride versus diamant
- Kubieke boornitride gebruikt
- Super abrasive wheels – or diamond c-BN wheel
Boornitride: An Overview
Boornitride is indicated by chemical formula “BN.” As earlier mentioned, Boornitride exist in different forms. Generally, it is the location of Boron and Nitrogen in lattice that creates various Boron Nitride structures. Some of them are quiet famous such as amorphous, hexagonal, cubic and Wurtzite.
When it comes to functionality, Boron Nitride ceramic is highly machinable. Once machined they does not really require any heat sintering or treatment for stabilization. In addition, Boornitride has higher heat capacity and is also a good electrical insulator.
For now, let’s try to understand derivatives of BN, Hexagonaal boornitride (h-BN) and another Kubieke boornitride (c-BN)
Hexagonaal boornitride (h-BN)
Structure of Hexagonal Boron Nitride
Hexagonaal boornitride is a constituent in many industrial products such as cosmetics. HBN has a structure controlled by covalent bonds. However, the layers in HBN obey wander Waals forces. The plate like geometry of HBN is the reason why it is ideal for lubrication.
Hexagonaal boornitride has elements of Boron and Nitrogen fixed to its lattice. The arrangement has three nitrogen atoms attached to a Boron Atom. The similarity in the honeycomb structure is the reason for its analogy with carbon. In addition to, properties of mechanical, chemical strength and electrical insulation are due to the planar triangular bonds
Properties of Hexagonal Boron Nitride
Hexagonaal boornitride is popularly manufactured through Boric Oxide nitridation at elevated temperatures. Since its stability is closer to graphene, Hexagonaal boornitride is often acclaimed as the most advanced technical ceramic. Some superior properties of Hexagonaal boornitride zijn de thermische geleidbaarheid en de lage wrijvingscoëfficiënt.
Toepassingen van hexagonaal boornitride
- HBN is used on nanoelectronics devices as a substitute to graphene substrate
- Hexagonaal boornitride in its thin form is used as coatings that resists corrosion
- HBN is often used in the manufacture of sensor materials. It is also used in electron tunneling due to its low value of dielectric constant.
Kubieke boornitride
What is cubic Boron Nitride?
c-BN is een derivaat van Hexagonaal boornitride (h-BN) produced under high temperature and pressure.
De grootste specialiteit van c-BN is dat het de tweede hardste materiaalsoort ter wereld is. De mechanische sterkte van Kubieke boornitride is populair en staat op gelijke voet met diamant. Het is een van de meest populaire polymorfen van boor. Nitride.
Structure of Kubieke boornitride
The basic structure of Kubieke boornitride is crystalline. It has density around 3.5 g/cm3 and appears in pale yellow or transparent complexion. C-BN follows alternate arrangement of Boron and Nitrogen atoms. Here, the Boorstikstof atoms follow covalent bonding which is the basic reason of its hardness and stability.
Cubic Boron Nitride Formula is given as c-BN. There are two popular types of c-Bn available today in the market. One is dense kubisch boornitride and the other polycrystalline cubic Boron Nitride.
Cubic Boron Nitride Properties
C-BN is a brilliant semiconductor whose bandgaps are susceptible to changes in applied pressure. These changes in bandgap helps them excel as electric insulators. Kubieke boornitride are generally inert and possesses low dielectric constant value. Their thermal conductivity is around 1300 KW/MK.
When it comes to reactivity, c-BN remains non-respondent even to ferrous materials. The optical range dealt by kubisch boornitride varies from Ultra violet to the visible spectrum.
Kubieke boornitride versus diamant
Hoewel niet harder dan diamant, kubieke boornitride heeft een bijzondere plaats vergeleken met diamant. Cubic boron Nitride hardness is 4500 Kg/mm2 whereas diamond has hardness around 600 Kg/mm2.The value of modulus both young’s and bulk are also in similar range of 800 – 1000 and 370 – 450.
Furthermore, when it comes to structure, like diamond, c-BN has its two base atoms that are different. The similarity of both diamond and c-BN is generally attributed to the lookalike structure they possess.
Kubieke boornitride gebruikt
cbn snijgereedschap materiaal
Kubieke boornitride exhibits both young’s and Bulk modulus greater than Boron Carbide and Silicon Carbide. This very reason strongly contributes to the hardness of cubic Boron Nitride. The hardness makes them suitable as abrasives and help them function as cbn snijgereedschap materiaal. Generally Dense c-Bn is used for cutting application and porous type for grinding requirements.
The inert nature of Cubic Boron Nitride also helps them function as cutting and machining material. Unlike diamond it doesn’t react to iron. However, conventional c-Bn requires manipulation for utilising it in cutting application. This is generally done during the conversion of h-Bn to c-Bn while sintering.
cbn as electrical insulators
Apart from hardness Kubieke boornitride also excels in electrical insulators. This is attributed to their wide bandgap.
cbn in semiconductor applications
By coating aluminium and Group 8 metals, C-BN functionality of becoming a sink is popular in electronic industry. C-BN is used as heat sink in lasers, microelectronic devices and LEDs.
Kubieke boornitride also adds value during semiconductor synthesis to obtain p and N type by proper doping. The common materials used for doping are Silicon or Beryllium. These semiconductors work at high temperature and are used in UV sensors.
c-BN slijpschijven
De uitvinding van c-BN slijpschijven merited precision manufacturing due to the increased efficiency. wheels made up of c-BN contributed to industries such as aerospace, machines, tool production and automobile. c-BN slijpschijven also offer high hardness and good performance on comparison with SiC and Alumina. They ensure structural integrity at higher temperature and undergo no degradation.
The wheels of c-BN can withstand high temperature and deals with the amount of heat generated during the process. The resistance to wear and tear is also economically beneficial while considering c-BN grinding wheels. c-BN grinding wheels offer excellent surface finish and keeps away the work piece wastage. It also ensures lesser cycle time as the tasks are done quickly and precisely.
Super abrasive wheels – or diamond c-BN wheel
The super abrasive wheels are the ones differ from conventional wheel of Sic and Alumina. They are made from combining c-Bn and diamond. The super abrasive wheel offers better thermal conductivity limiting the rise in temperature of the workpiece. The diamanten c-Bn wiel bieden ook een hoge nauwkeurigheid en precisie bij het snijden, wat bijdraagt aan een langere levensduur.
Conclusie
Kubieke boornitride is wenselijk in de moderne wetenschap en materiaalproductie. Ze zijn concurrerend in vergelijking met materialen zoals diamant. Ze blinken uit in eigenschappen zoals hardheid, sterkte en elektrische isolatie. De brede band gap, inerte aard, lage diëlektrische constante en optische specialiteiten zijn andere factoren die van belang zijn.