1. The lubricity of boron nitride
Boron nitride came out more than 100 years ago. The application polymorph is hexagonal boron nitride as a high-temperature lubricant, abbreviated as: h-BN, or a-BN, or g-BN (that is, graphite-type boron nitride), hexagonal nitride Boron is smooth, and the friction coefficient between the powders is very low. Each layer of its atomic structure contains boron and nitrogen. There is no BN bonding between the layers, so the planes slide between each other to obtain a soft and lubricating effect. It is suitable for application as a high temperature release agent. Monomer boron
From the application occasion or the downstream product system of the application, there are generally the following types:
Various optical glass release agents
Mold release agent for metal forming and lubricant for metal wire drawing
Metallurgical separation ring used for continuous steel casting, etc.
2. Advantages of Boron Nitride Release Agent
Good lubricity: special fine powder blending, strong and effective adhesion to the mold surface, forming an excellent lubrication effect.
Can prolong the life of the mold: effectively reduce mold loss and reduce the time required to clean the mold. During the glass processing, the surface defects of the glass product can be reduced to make the glass easier to demold.
Good operability: Special spray formula can be evenly coated on the surface of the mold using manual methods.
High temperature resistance: Excellent thermal shock resistance, even if the temperature is 1500℃, the rapid heating and cooling will be repeated several times, but it will not break, even if it is heated to 2200℃, it can still be used with peace of mind.
Fast drying speed: special quick-drying formula, fast drying speed, improve production efficiency and reduce costs.
Low friction coefficient: The friction coefficient u is only 0.16, which does not increase at high temperature. It is more resistant to high temperature than molybdenum disulfide and graphite. The oxidizing atmosphere can be used up to 800°C, and it can be used up to 2000°C under vacuum.
Good corrosion resistance: with general metals (iron, copper, aluminum, lead, etc.), rare earth metals, precious metals, semiconductor materials (germanium, silicon, potassium arsenide), glass, molten salt (crystal stone, fluoride, slag ), inorganic acids and alkalis do not react.
Machinability: Its Mohs hardness is 2, so it can be processed into high-precision parts products by general machining methods
Third, the application of boron nitride release agent in the release of glass molds
With the rapid development of my country's alcohol, food, beverage and other industries, the demand for all kinds of packaging glass bottles and cans has increased. The determinant bottle making machine has become the mainstream model for glass bottle production and is widely used, and the running speed of the determinant bottle making machine is getting faster and faster, and the requirements for the lubricating release agent of the glass mold are getting higher and higher. The traditional method of lubricating and demolding glass molds uses manual application or mechanical spraying of animal and vegetable oils, which generally do not work well.
The use of boron nitride lubricating material significantly improves the lubrication and demoulding effect. At present, the most widely used boron nitride release agents are mainly divided into the following three categories:
One type uses water as the medium, adding high-temperature adhesives and other additives to make a water-based lubricant, which is applied to the surface of the mold at one time, and used after drying to form a film.
The other type uses oil as the medium and adds additives to make oily lubricants, which are continuously brushed or sprayed during the operation of the line-type bottle making machine.
A commonly used boron nitride release agent is to coat high-viscosity mineral oil with boron nitride and mix with water under the action of an emulsifier to make an emulsified oil type lubricating release agent for glass molds. When boron nitride: grease: water = 1:4:10, and the emulsifier dosage is 7wt%, the prepared emulsified oil release agent has good stability, good release performance, and has the characteristics of thin oil film and uniform distribution. The use of boron nitride lubricating mold release agent improves the yield of bottle making, reduces the consumption of lubricating mold release agent, and purifies the production environment.
Boron nitride release agent can also be applied to flat glass processing, which can greatly improve the working environment and increase product efficiency. Especially used for curved glass processing, the effect is more significant:
Highly difficult deep bends, special shapes, hot melt, clear light, etc.
4. Application of Boron Nitride Release Agent in Metal Casting Melting and Welding
Hexagonal boron nitride has excellent chemical stability and can withstand the neutron radiation of nuclear reactors, and neither acid nor alkali can affect it. In an inert atmosphere (nitrogen or argon), the decomposition temperature is as high as 2500°C, which exhibits extreme conditions. Excellent chemical stability.
Hexagonal boron nitride can be made into boron nitride separation ring for horizontal continuous casting of steel. Hexagonal boron nitride is very stable to carbon and carbon monoxide at 1800°C, and it is not corroded by molten glass, silicon, boron, non-oxide slag, and molten salt (borax, cryolite) in steel.
Hexagonal boron nitride can be made into a composite shell for titanium casting. Titanium metal has poor chemical stability. When forging is severely deformed at high temperature, it is very easy to stick to the mold when the metal flows and produces a fresh surface, causing the forging and the mold to be scrapped at the same time. The boron nitride release agent composite shell layer is coated on the surface of the mold to avoid direct contact between the titanium metal and the mold.
Hexagonal boron nitride can also be used for welding and brazing in the furnace, which can protect the surface of the workpiece from damage due to the splash of welding slag, and can also play a protective role in the metal welding process.
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