Boron Nitride cbn is an advanced ceramic known for its superior properties. BN chemistry has Nitrogênio de boro 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
Nitreto de boro: uma visão geral
Nitreto de boro hexagonal (h-BN)
- Structure of Hexagonal Boron Nitride
- Properties of Hexagonal Boron Nitride
- Aplicações do Nitreto de Boro Hexagonal
- What is cubic Boron Nitride?
- Structure of Cubic Boron Nitride
- Propriedades do nitreto de boro cúbico
- Nitreto de Boro Cúbico vs. Diamante
- Usos do nitreto cúbico de boro
- Super abrasive wheels – or diamond c-BN wheel
Nitreto de boro: An Overview
Nitreto de boro is indicated by chemical formula “BN.” As earlier mentioned, Nitreto de boro 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, Nitreto de boro has higher heat capacity and is also a good electrical insulator.
For now, let’s try to understand derivatives of BN, Nitreto de boro hexagonal (h-BN) and another Nitreto de boro cúbico (c-BN)
Nitreto de boro hexagonal (h-BN)
Structure of Hexagonal Boron Nitride
Nitreto de boro hexagonal 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.
Nitreto de boro hexagonal 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
Nitreto de boro hexagonal is popularly manufactured through Boric Oxide nitridation at elevated temperatures. Since its stability is closer to graphene, Nitreto de boro hexagonal is often acclaimed as the most advanced technical ceramic. Some superior properties of Nitreto de boro hexagonal são sua condutividade térmica e baixo coeficiente de atrito.
Aplicações do Nitreto de Boro Hexagonal
- HBN is used on nanoelectronics devices as a substitute to graphene substrate
- Nitreto de boro hexagonal 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.
Nitreto de boro cúbico
What is cubic Boron Nitride?
c-BN é um derivado de Nitreto de boro hexagonal (h-BN) produced under high temperature and pressure.
A maior especialidade de c-BN é que ele ocupa o lugar de segundo material mais duro do mundo. A resistência mecânica do Nitreto de boro cúbico é popular e está no mesmo nível do diamante. É um dos polimorfos mais populares do Boro Nitreto.
Structure of Nitreto de boro cúbico
The basic structure of Nitreto de boro cúbico 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 Nitrogênio de boro 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 nitreto de boro cúbico 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. Nitreto de boro cúbico 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 nitreto de boro cúbico varies from Ultra violet to the visible spectrum.
Nitreto de Boro Cúbico vs. Diamante
Embora não seja mais duro que o diamante, nitreto de boro cúbico tem seu lugar especial quando comparado ao diamante. 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.
Usos do nitreto cúbico de boro
material de ferramenta de corte cbn
Nitreto de boro cúbico 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 material de ferramenta de corte cbn. 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 Nitreto de boro cúbico 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.
Nitreto de boro cúbico 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.
rodas de desbaste c-BN
A invenção de rodas de desbaste c-BN 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. rodas de desbaste c-BN 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 roda de diamante c-Bn também oferecem alta precisão e exatidão de corte que contribuem para uma maior vida útil.
Conclusão
Nitreto de boro cúbico É desejável na ciência moderna e na fabricação de materiais. São competitivos quando comparados a materiais como o diamante. Destacam-se em propriedades como dureza, resistência e isolamento elétrico. A ampla lacuna de banda, a natureza inerte, a baixa constante dielétrica e as especialidades ópticas são outros fatores de mérito.