Introduction
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 have been identified as the most effective refractory materials for high temperatures. In this article, you will learn about PBN, and PG, their differences, their real-world application, and how viable the business can be if you have an interest in that area.
Difference Between Pyrolytic Boron Nitride (PBN) and Pyrolytic Graphite (PG)
PBN/PG
Pyrolytic boron nitride is a high-quality ceramic material produced through chemical vapor deposition. It’s sometimes called chemical vapor-deposited boron nitride – more commonly represented as PBN. On the other hand, Pyrolytic graphite is a special graphite produced by decomposing hydrocarbon gas at extremely high temperatures in a vacuum furnace.
Appearance, Strength, and Other Properties
PBN has either an orange or ivory appearance. The density of the material is 2.15 g/cm3, and the surface is very smooth without pores. The compound is odorless and has a slippery structure. Furthermore, the tensile strength that defines this refractory material is 153.84 N/mm2 and its elastic modulus is 235690 N/mm2, having a dielectric strength of 56k V/mm at room temperature. The ceramic composite doesn’t easily crack with changes in temperature due to its adequate thermal shock resistance.
More so, 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.
Fig 1: Pyrolytic boron nitride (PBN)
PG has a black solid appearance and can be in the form of a disc, sheet, or plate. It has an ultimate tensile strength of 200 MPa. In addition, its density falls between 1.30 and 2.265 g/cm3. It also has a perpendicular thermal conductivity of 80 W/m·K
Additionally, PG can withstand thermal expansion of up to 20 µm/m·°C. Its perpendicular electrical resistivity falls between 0.15 and 0.25 Ω·cm. Thus, its ultimate strength under compression, bending, and tension rises with increased temperature.
Fig. 2: Pyrolytic graphite (PG)
Application of Pyrolytic Boron Nitride (PBN) and Pyrolytic Graphite in High-Temperature Environments
High-Power Electronics
PBN comprises ceramic matrix nanocomposites making it good for electrical insulation. This allows it to function in high temperatures without suffering degradation. Therefore, they are ideal for ensuring the stability of extreme thermal energy generation.
On the other hand, the function of PG in high-energy electronics is that of a heat spreader. It effectively dissipates generated heat from electrical components to ensure prolonged reliability and functionality.
Semiconductor Manufacturing
PBN and PG also play a significant role in the semiconductor industry. Crystal growth in semiconductors is enhanced using a PBN crucible because of its pure properties and capacity to ensure thermal stability. This allows electronic components to perform optimally due to the absence of contamination.
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: PBN crucible
Nuclear Reactor Components
The refractory ceramic material in PBN and PG allows them to hold out under extreme radiation and heat. PG particularly has a high level of stability, making it a suitable material for designing reactor cores. In contrast, the properties of thermal insulation and chemical stability in PBN ensure the safety and efficiency of reactor components.
Aerospace Engineering
The ceramic composites of pyrolytic boron nitride and highly ordered pyrolytic graphite allow them to withstand extremely high temperatures. Hence the reason why they constitute the materials used for designing spacecraft. They are the refractory lining materials integrated by aerospace engineers into spacecraft to facilitate seamless function during flight and re-entry.
In particular, PG is composed of cmc composites that reinforce its capacity for thermal conduction. This allows them to function as heat shields to dissipate heat and protect sensitive spacecraft components.
PBN comprises refractory and ceramic properties allowing for chemical stability and thermal insulation, protecting the spacecraft components from corrosion and high temperature.
Medicine
PBN and PG form the components of applications used in the medical field, especially for high-temperature sterilization apps. PBN is specifically used in those high-temp apps to provide thermal stability and biocompatibility. This thermal stability allows for the production of medical implants that can survive intense conditions without being mordant.
Microwave and RF Applications
The thermal stability and insulation properties of PBN allow it to function as components of windows and substrates in microwaves. Where microwaves are utilized in high temperatures, PBN’s ceramic body material makes provision for efficiency.
Pyrolytic graphite can efficiently dispel heat in RF devices and ensure efficient functioning. To a large extent, RF devices can perform optimally due to the highly ordered pyrolytic graphite (hopg).
The Lucrative Business of PGN and PG
Pyrolytic boron nitride (PBN) and pyrolytic graphite (PG) carry huge potential 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.
PBN-PG composite heating elements are very durable. Chemical-vapor deposition (CVD) is used to place PG on the PBN elements to create durable ceramics used in semiconductors. These semiconductors are components of microchips in laptops, mobile phones, robots, etc. This means that PBN-PG composite heating elements are in high demand.
If you want to venture into this business, then you are sure of great profit and growth. PBN-PG composite heating elements offer more efficient options to engineers, especially producers of laptops, mobile phones, tablets, etc. giving them an option to create products that easily dissipate heat.
Fig 4: PBN-PG Composite heating element
PBN is an ideal product component of break rings for horizontal casting machines. If you also need an insulator for a high-temperature furnace, you would be better off using PBN. They also function as electric insulators for vacuum systems.
Furthermore, highly oriented pyrolytic graphite (HOPG) is utilized in x-ray spectrometry – it’s a dispersive component in HOPG spectrometers. Producers in the plastic industry use PG to reinforce plastic products, and it also plays a role in the automotive industry by applying a certain level of friction between two components.
Frequently Asked Questions (FAQs)
What is the Key Distinction Between Pyrolytic Boron Nitride (PBN) and Pyrolytic Graphite (PG)?
The key distinction between PBN and PG lies in their composition. PG has a significantly higher thermal conductivity than PBN – PG is an electrical conductor while PBN is an insulator. Due to those properties, PBN is more efficient in terms of high thermal resistance.
What Is A Refractory Material?
A refractory material is simply a thermal insulator. They are materials with properties that enable them to withstand extremely high temperatures. They are also highly resistant to chemical attacks and shocks.
Conclusion
Pyrolytic boron nitride and pyrolytic graphite are making giant strides in the electronic and aerospace industries. Particularly, PBN ensures thermal resistance, shielding components of high-temperature devices from damage due to high temperatures. PG dissipates heat in electrical components.