Introdução
Pyrolytic Boron Nitride (PBN) and Pyrolytic Graphite (PG) have taken center stage when dealing with the functionality of high-temperature applications. This is because they are very efficient materiais refratários. In this article, you will learn about PBN, and PG, their differences, real-world applications and how lucrative the business is in case you’re looking to invest.
Diferença entre nitreto de boro pirolítico (PBN) e grafite pirolítico (PG)
Pyrolytic boron nitride is a high-purity ceramic material produced through chemical vapor deposition. It is odorless and has a crystal structure that is hexagonal which makes people easily mistake it for Graphite. It goes by the trade name, PBN. Pyrolytic Boron Nitride is one of the strongest and purest forms of boron nitride (about 99.9% purity). The reason for this is because of the closely packed anisotropic structure and the intense heat it undergoes while being produced.
Pyrolytic graphite is a special graphite produced by decomposing hydrocarbon gas at extremely high temperatures in a vacuum furnace.
Characteristics of Pyrolytic Boron Nitride And Pyrolytic Graphite
PBN mostly has an orange or whitish appearance with a density of 2.15 g/cm3. The surface is smooth and without pores. The tensile strength of PBN is an impressive 153.84 N/mm2 and its elastic modulus is 235690 N/mm2. It has a dielectric strength of 56k V/mm and a very high thermal shock resistance which makes it able to withstand mechanical stress.
PBN’s strength increases with a rise in temperature until it reaches 2473o K. When the temperature rises to 3273o K, the pyrolytic boron nitride compound disintegrates into boron and nitride. Pyrolytic boron nitride has a low coefficient of expansion (2.1 x 10-6°/C) which makes it maintain a stable shape even under extreme temperatures and pressure.
Furthermore, the fact that it is chemically inert means it doesn’t get rust easily. Why? It’s sufficiently able to resist attacks from chemicals or acids.
Fig 1: Nitreto de boro pirolítico (PBN)
PG is a black solid that occurs mostly in the form of a disc, sheet, or plate. It has an ultimate tensile strength of 200 MPa. Its density falls between 1.30 and 2.265 g/cm3. It also has a perpendicular thermal conductivity of 80 W/m·K
Além disso, o PG pode suportar expansão térmica de até 20 µm/m·°C. Sua resistividade elétrica perpendicular varia entre 0,15 e 0,25 Ω·cm. Assim, sua resistência máxima à compressão, flexão e tração aumenta com o aumento da temperatura.
Fig. 2: Grafite pirolítico (PG)
Applications of Pyrolytic Boron Nitride (PBN) and Pyrolytic Graphite in High-Temperature Environments
Eletrônica de alta potência
PBN comprises ceramic matrix nanocomposites making it good for electrical insulation and allowing it to be stable and function effectively in high temperatures. It also means PBN can also help you produce high strength wafers for any high temperature demanding - power electronics device.
Pyrolytic Graphite tends to act more as an efficient heat dissipator in high-energy electronics you see today. It can make your equipment and gadgets last longer without overheating. PBN can also help you manufacture OLED Displays and LED Lights for electronics.
Fabricação de semicondutores
PBN and PG also play a significant role in the semiconductor industry. Crystal growth and efficient heat dissipation in semiconductors is enhanced using a Cadinho PBN devido às suas propriedades puras e à capacidade de garantir estabilidade térmica. Isso permite que os componentes eletrônicos tenham um desempenho ideal devido à ausência de contaminação.
Uniform heating in the wafer manufacturing process of semiconductors is the function of highly oriented pyrolytic graphite (HOPG). It’s this function that ensures the process of semiconductor fabrication. 
Fig 3: Cadinho PBN
Componentes do Reator Nuclear
O material cerâmico refratário presente em PBN e PG permite que eles resistam a radiação e calor extremos. O PG, em particular, possui um alto nível de estabilidade, tornando-o um material adequado para o projeto de núcleos de reatores. Em contraste, as propriedades de isolamento térmico e estabilidade química do PBN garantem a segurança e a eficiência dos componentes do reator.
Engenharia Aeroespacial
The refractory linings of aerospace machines, aeroplanes and jets make use of pyrolytic boron nitride materials because they tend to facilitate seamless function during flight and re-entry.
In particular, PG is composed of cmc composites that reinforce its capacity for thermal conduction which makes it a good heat shield to sensitive spacecraft components.
Medicamento
Most equipment used in sterilization use components made from PBN and PG due to the thermal stability it can provide as well as its biocompatible nature. This thermal stability allows for the production of medical implants that can survive intense conditions without being mordant.
Aplicações de micro-ondas e RF
The thermal stability and insulation properties of PBN allows it to function as major components of windows and substrates in microwaves. Highly Ordered Pyrolytic Graphite (HOPG) can also efficiently dissipate heat in RF devices and make them function at an optimal level.
O negócio lucrativo de PGN e PG
Pyrolytic boron nitride (PBN) and pyrolytic graphite (PG) carry huge potentials for major innovations in several lucrative industries. For instance, being in the PBN and PG business gives you an edge in the electrical industry. This is because of the rise in the interest of PBN-PG composite heating elements.
Os elementos de aquecimento compostos de PBN-PG são muito duráveis. A deposição química de vapor (CVD) é usada para depositar PG nos elementos de PBN, criando cerâmicas duráveis usadas em semicondutores. Esses semicondutores são componentes de microchips em laptops, celulares, robôs, etc. Isso significa que os elementos de aquecimento compostos de PBN-PG estão em alta demanda.
Se você deseja se aventurar neste negócio, certamente terá grande lucro e crescimento. Os elementos de aquecimento compostos de PBN-PG oferecem opções mais eficientes para engenheiros, especialmente fabricantes de laptops, celulares, tablets, etc., permitindo-lhes criar produtos que dissipam calor facilmente.
Fig 4: Elemento de aquecimento composto PBN-PG
PBN is an ideal product component of break rings for horizontal casting machines. If you also need an insulator for a high-temperature furnace or vacuum system, you would be better off using PBN.
Furthermore, highly oriented pyrolytic graphite (HOPG) is utilized in x-ray spectrometry as a dispersive component. Manufacturers in the plastic industry use PG to reinforce plastic products. PBN also plays a key role in the automotive industry due to its effective wear resistance as it helps to increase the longevity of motor spare parts or even the engines by reducing wear and tears from friction.
Perguntas Frequentes (FAQs)
Qual é a principal distinção entre nitreto de boro pirolítico (PBN) e grafite pirolítico (PG)?
A principal diferença entre PBN e PG reside em sua composição. O PG possui uma condutividade térmica significativamente maior que o PBN – o PG é um condutor elétrico, enquanto o PBN é um isolante. Devido a essas propriedades, o PBN é mais eficiente em termos de alta resistência térmica.
O que é um material refratário?
Um material refratário nada mais é do que um isolante térmico. São materiais com propriedades que os permitem suportar temperaturas extremamente altas. São também altamente resistentes a ataques químicos e choques.
Conclusão
O nitreto de boro pirolítico e a grafite pirolítica estão avançando a passos largos nas indústrias eletrônica e aeroespacial. Em particular, o PBN garante resistência térmica, protegendo componentes de dispositivos de alta temperatura contra danos causados por altas temperaturas. O PG dissipa o calor em componentes elétricos.