Halogen-free composite flame retardants are essential for fire protection. Their main components are quite complex, and they are made up of several substances, each performing its own duties, in order to achieve flame retardant effect.
One is an inorganic flame retardant, and the common ones are aluminum hydroxide and magnesium hydroxide. When the two are heated, dehydration occurs. At about 200-300 ° C, aluminum hydroxide loses water and converts to aluminum oxide, and magnesium hydroxide has similar changes at slightly higher temperatures. The water loss process requires heat absorption, which can reduce the surface temperature of the material, and the generated water vapor can dilute flammable gases and slow down the combustion rate. Alumina and magnesium oxide are both stable solids, which can form a dense protective film on the surface of the material, isolating oxygen and combustible materials and preventing the spread of combustion.
The second is phosphorus-based flame retardants, such as phosphate esters, phosphonitriles, etc. When burned, phosphorus-based flame retardants will decompose to form phosphoric acid, metaphosphoric acid and other substances. These phosphorus-containing compounds can promote the dehydration and carbonization of the polymer to form a carbonaceous layer. This carbonaceous layer has poor thermal conductivity, can effectively block heat transfer, and can prevent oxygen from contacting the polymer, thus playing a flame retardant role. At the same time, the volatile phosphorus compounds produced by the decomposition of phosphorus-based flame retardants capture free radicals in the combustion reaction in the gas phase, inhibit the chain reaction of combustion, and extinguish the flame.
The third is nitrogen-based flame retardants, melamine and its derivatives are common examples. When nitrogen-based flame retardants are thermally decomposed, they release non-combustible gases such as nitrogen and ammonia. These gases can dilute the concentration of flammable gases and oxygen, reduce the oxygen content in the combustion area, and make combustion unsustainable. In addition, its decomposition products can promote the carbonization of polymers, enhance the stability of the carbon layer, and improve flame retardancy.
Another category is intumescent flame retardants, which are usually composed of acid sources, carbon sources, and gas sources. When heated, the acid source decomposes to produce acid, which prompts the carbon source to dehydrate and carbonize, and the gas source decomposes to release gas, causing the carbonization layer to expand to form a porous foam-like carbonaceous layer. This carbonaceous layer acts as a strong barrier, insulating heat and oxygen, effectively preventing the spread of flames and achieving good flame retardant effect.
Halogen-free composite flame retardants play a flame retardant role in the condensed phase and the gas phase by cooperating with each other. They not only ensure fire safety, but also meet the needs of environmental protection. They are widely used in many fields and contribute greatly to the protection of world safety.

The ballast resistance principle of ballastless composite track fasteners is a design that integrates mechanics, materials science and many other delicacies. Its core meaning is to realize the stability and restraint of the ballast through specific structures and material characteristics, so as to prevent it from displacing under the action of train loads.
Looking at the structure of its fasteners, there are many components working together. Taking the gusset as an example, its shape and installation angle are carefully designed. When it is pressed on the surface of the ballast, it will generate downward and inward forces through its own elastic deformation. This force is like an invisible hand, pressing the ballast tightly and restricting it to a specific position, making it difficult for the ballast to loosen and shift due to external impact.
Furthermore, the material used for the fastener is also crucial. It has moderate rigidity and toughness. The rigidity ensures that the fastener structure will not easily deform and fail when it bears the repeated load of the train; the toughness allows the fastener to buffer energy under long-term vibration and impact, and will not break due to stress concentration. It always maintains an effective constraint on the ballast.
There are anchoring components, which are firmly embedded in the track bed and closely integrated with the ballast. This component is like a root system rooted in the ground, providing a solid foundation for the entire fastener system, so that the fastener is still stable as before when it bears the lateral and vertical forces of the ballast, thus further strengthening the blocking of the ballast, making it difficult for the ballast to leave the established position, ensuring the stability of the track structure, and providing a strong guarantee for the smooth operation of the train. In this way, ballastless composite track fasteners with exquisite construction and high-quality materials achieve excellent ballast resistance and play a key role in railway engineering.

Flame-free composite flame retardants are suitable for many materials, and let me explain in detail why.
For materials such as wood, flameless composite flame retardants are very suitable. Wood is flammable and is widely used in construction, furniture and other fields. If the fire resistance is poor, it is easy to cause fires. Flame-free composite flame retardants can form a continuous and dense protective film on the surface of wood by physical or chemical action. This film can block the transfer of oxygen and heat to the interior of the wood, slow down the thermal decomposition rate of wood, and reduce the production of flammable volatiles, thereby achieving efficient flame retardancy and greatly improving the safety of wood in fire.
Plastic materials are also suitable for flameless composite flame retardants. Plastics are widely used, covering electronics, automotive interiors, and many other aspects. Flame-free composite flame retardants can be well compatible with plastics without affecting the original physical and mechanical properties of plastics. It can decompose non-gaseous bodies when heated, dilute the concentration of flammable gases, and the decomposition products can promote the carbonization of the plastic surface, forming a carbon layer. This carbon layer acts as a heat and oxygen barrier, effectively preventing further combustion of plastics and ensuring the safety of plastic products.
Fiber materials also benefit from flameless composite flame retardants. Whether it is natural fibers such as cotton and linen, or synthetic fibers such as polyester fibers, the flame retardant performance is greatly improved after being treated with flameless composite flame retardants. Its mechanism of action may be to change the thermal decomposition path of fibers and reduce the generation of flammable gases; or to form molten glass-like substances on the surface of fibers to cover fibers and isolate air, thereby achieving flame retardancy, making fiber products safer and more reliable when used in clothing, home textiles and other fields.
In short, flameless composite flame retardants are widely used in wood, plastic, fiber and other materials due to their unique principle of action and performance advantages, providing a strong guarantee for the safe application of these materials in various fields.

"Tiangong Kaiwu" says: "Where a bell is cast, the higher one is made of copper, and the lower one is made of iron. Today's lead-free composite crucibles, in order to achieve their best environmental performance, need to be carefully studied from the selection of materials and production methods.
First discuss the selection of materials. To achieve environmental protection, choose pure and less impurity raw materials. If you want to extract ore, carefully observe the ore veins, choose those with pure texture, and discard those with more contaminants. This is the basis. If the material is pure, there will be less harmful volatilization during casting, and light pollution to the surrounding environment.
Second words. First, the control of the fire is the key. The size and duration of the fire are all related to the product. If the fire is too strong, the raw materials may cause excessive wear and tear, and all kinds of harmful smoke will be produced; if the fire is insufficient, the raw materials will not be fully integrated and the products will be impure. When precise skills are used, the heat should be adjusted to the right extent, so that the raw materials can fully react and produce less filth. Second, the materials and systems of the casting mold are also exquisite. The mold materials are selected from natural and harmless ones, such as special clay, which is gentle in nature and does not produce toxic fumes. When making molds, strive for precision to avoid leakage of molten liquid and defacement of the environment. Third, post-casting treatment should not be ignored. When the utensils are ready, remove their burrs and debris, and properly dispose of the discarded things. They cannot be discarded at will, causing sewage and soil.
In this way, from the selection of materials, through the fineness of the production method, until after the casting, the lead-free composite crucible can be expected to have good environmental performance, and the environment is not damaged in the casting industry. It is also in the realm of harmony between heaven and man.

Compared with halogen-free flame retardants, halogen-free composite flame retardants have many advantages.
The first is the benefit of environmental protection. In today's world, environmental protection is the most important. When halogen-containing flame retardants are heated or burned, harmful gases such as hydrogen halide are often released. They are corrosive and highly toxic. They not only endanger human health, but also cause casualties in the event of a fire. They are also far-reaching to the environment and destroy the atmospheric ozone layer. Halogen-free composite flame retardants are not so worried. The release of harmful gases such as hydrogen halide during combustion is in line with the current trend of environmental protection and is friendly to the environment and human health.
Furthermore, halogen-free composite flame retardants have good thermal stability. In case of high temperature, it can maintain good flame retardant properties and does not easily decompose and fail. This characteristic allows it to play a long-term flame retardant effect in high temperature environments or materials that need to be heated for a long time to ensure the safety of the material.
Halogen-free composite flame retardants also have excellent compatibility. It is well compatible with many polymer materials. During the processing of the material, it will not affect the original physical and mechanical properties of the material. The strength, toughness and processability of the material can be maintained at an ideal level, unlike some halogen-containing flame retardants or damage the properties of the material.
Halogen-free composite flame retardants also have smoke suppression properties. In a fire, smoke is also a major hazard, which obscures the line of sight and hinders people's escape and rescue operations. The amount of smoke produced by halogen-free composite flame retardants during combustion is small, which helps to improve the visibility in the event of a fire, and strives for more opportunities for evacuation and fire fighting.
In summary, halogen-free composite flame retardants have shown significant advantages over halogen-containing flame retardants in many aspects such as environmental protection, thermal stability, compatibility and smoke suppression, and have gradually become the development trend in the field of flame retardant materials.