Hexagonal boron nitride is insoluble in cold water and hydrolyzes very slowly when boiled and produces small amounts of boric acid and ammonia. It does not react with weak acids and strong bases at room temperature, is slightly soluble in hot acids, and needs to be treated with molten sodium hydroxide and potassium hydroxide to decompose.

The advantages of boron nitride:

1, high heat resistance: 3000 ° C sublimation, its strength 1800 ° C for the room temperature of two times, 1500 ° C air cooling to room temperature dozens of times without rupture, inert gas 2800 ° C does not soften.

2, high thermal conductivity: hot pressing products for 33W/M.K and pure iron, as in 530 ℃ above the ceramic material is the largest thermal conductivity materials.

3, low coefficient of thermal expansion: coefficient of expansion is second only to quartz glass, is the smallest in ceramics, coupled with its high thermal conductivity, so the resistance to thermal shock performance is very good.

4, excellent electrical properties: high-temperature insulation is good, the resistivity at room temperature is greater than 10 ^ 14 Ω - cm, at 2000 ℃ can also reach 10 ^ 3 Ω - cm, is the best high-temperature insulation material in ceramics.

5, good corrosion resistance: and general metals (iron, copper, aluminum, lead, etc.), rare earth metals, precious metals, semiconductor materials (germanium, silicon, potassium arsenide), glass, molten salts (cristobalite, fluoride, slag), inorganic acids, alkalis do not react.

6, lower coefficient of friction: U is 0.16, high temperature does not increase, than molybdenum disulfide, graphite, high temperature, oxidizing atmosphere can be used up to 850 ℃, vacuum can be used up to 1800 ℃.

7, high purity: its impurity content is less than 10PPM, while the boron content is more than 43.6%.

8, machinability: low hardness, can be general machining methods into very high precision parts and components products.

Boron nitride ceramic materials have excellent machinability and can be machined into complex shapes with extremely tight tolerances as required.
Boron nitride ceramic materials should be processed with attention to the following matters:

1, boron nitride ceramic materials can be processed using standard high-speed steel cutting tools, for the processing of harder composite materials, the recommended use of carbide tools or diamond tools.

2、It can be ground and processed according to the needs, and can use standard taps and plate teeth to process threads.

3. The machining process should always be dry, without the use of cutting oil and coolant.

4, cutting tools should be sharp and clean, do not use negative inclination of the cutting tool.

5. When processing the material, care should be taken when jamming and clamping to avoid applying excessive pressure, and the smooth milling technique should be used to prevent the generation of missing edges and corners.