Properties And Applications Of Hexagonal Boron Nitride Ceramics

Characteristics of Boron Nitride Ceramics

(1) High heat resistance

h-BN ceramics are sublimated at 3000°C in 0.1MPa nitrogen, and the strength at 1800°C is twice that of room temperature.

(2) High thermal conductivity

The thermal conductivity of hot-pressed h-BN ceramic products is about 33W/m•k, which is similar to that of stainless steel, and is one of the materials with the highest thermal conductivity among ceramic materials.

(3) Low coefficient of thermal expansion

The coefficient of linear expansion of h-BN ceramics is (2.0~6.5)×10-6/℃, second only to quartz glass, and is the smallest among ceramics. In addition, it has high thermal conductivity, so h-BN ceramics are thermal shock resistant. The performance is very good.

(4) Excellent electrical insulation properties

The high-temperature insulation of h-BN ceramics is good. Its resistivity is 1014Ω•cm at 25°C, and can reach 103Ω•cm at 2000°C. The maximum volume resistivity of high-purity h-BN ceramics can reach 1016~1018Ω•cm, even at 1000 ℃ high temperature, there are still 104~106Ω•cm, which is the best high-temperature insulating material among ceramics.

(5) Good corrosion resistance

h-BN ceramics have good chemical stability and are not wetted by most molten metals, glasses and salts, so they have high corrosion resistance to acids, alkalis, molten metals and glasses, and good chemical inertness.

(6) Low coefficient of friction

h-BN ceramics have excellent lubricating properties, the friction coefficient μ is 0.16, does not increase at high temperature, and has higher temperature resistance than molybdenum disulfide and graphite. The oxidizing atmosphere can reach 900°C, and it can reach 2000°C under vacuum.

(7) Machinability

h-BN ceramics are very easy to use conventional metal cutting technology to finish the products, and the turning accuracy can reach 0.05mm, so products with complex shapes can be processed from h-BN blanks.

Application of Boron Nitride Ceramics

Boron nitride ceramics can be said to be a new industrial material developed with the development of the aviation and electronics industries, and has broad application prospects in the fields of metallurgy, chemical industry, electronics and new energy.

Utilizing the good high temperature resistance and electrical insulation of boron nitride products, it can be used as electrical insulation materials at high temperatures, and has excellent thermal shock resistance. Utilizing its high thermal conductivity and penetrating performance to microwave radiation, it can be used as a transmission window for radar in the electronics industry. Utilizing the high melting point, small thermal expansion coefficient and stable performance of almost all molten metals, h-BN products can be used as high-temperature metal smelting crucibles, heat-resistant materials, heat sinks and heat-conducting materials. Utilizing the excellent thermal stability of h-BN ceramics, it can be used under repeated rapid cooling and rapid heating conditions from 1500°C to room temperature.

Utilizing the good corrosion resistance of h-BN ceramics to acid, alkali and glass slag, and the performance of neither wetting nor reaction to most molten metals, it can be used as a crucible for melting non-ferrous metals, precious metals and rare metals, Vessels, pipes, delivery pumps and other components. The use of h-BN ceramics is not only a good conductor of heat, but also an electrical insulator, and can be used as an ultra-high temperature insulating material. The use of h-BN ceramics is transparent to microwaves and infrared rays, and can be used as a window for infrared and microwave transmission, such as radar windows .

The use of ceramics has a strong neutron absorption capacity, and can be mixed with various plastics and graphite in the atomic energy industry as a shielding material for atomic piles. Using h-BN ceramics has high thermal stability, chemical stability and electrical insulation, and also has the characteristics of high thermal conductivity, good dielectric properties, and easy processing of products, and can be combined with TiB2 to prepare conductive ceramic evaporation boats.

In addition, h-BN has stable performance under ultra-high pressure and can be used as a pressure transmission material and container. Utilizing h-BN is the lightest ceramic material, which can be used as a high-temperature structural material for aircraft and spacecraft. Utilizing the luminescence of h-BN, it can be used as an electroluminescent material.

In general, different levels of hexagonal boron nitride particles (nanoscale, several micron-scale, tens of micron-scale particles) have different applications. Among them, nano-sized particles have small particle size and good lubricity, and will be used in lubricating oil additives, cosmetics and other industries; several micron-sized particles have good heat resistance, low thermal expansion coefficient, and good electrical insulation, and will be used in high-temperature resistant coatings and synthetic cubic nitrogen. Boronization, preparation of special ceramics and other industries; dozens of micron-sized particles have good thermal conductivity and stable chemical properties, and will be used in thermal conductive materials, aerospace materials, electrical materials and other fields.

Shengyang New Material Co., Ltd. is committed to the production of boron nitride and boron nitride processed products, and can customize various boron nitride insulating ceramic parts according to customer needs. Contact us if necessary.

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