Mg-Al alloy, also known as Al-Mg alloy, molecular formula: Mg4Al3 molecular weight: 178.22 The color is taupe, the specific gravity is about 2. 15g/cm3, the melting point is 463℃, and the temperature generated during combustion reaches 2000℃-3000℃. It plays a very important role as reducing agent in fireworks production, and can also be used as white light agent and luminous agent. Magnesium-aluminum alloy is formed by melting magnesium ingots and aluminum ingots in protective gas at high temperature. There have been two opinions about the microstructure of magnesium-aluminum alloy for a long time. One theory holds that magnesium-aluminum alloy is a simple physical mixture; Another way of saying this is that the crystal structure of Mg-Al alloy is internally changed, not simply physically mixed. When magnesium ingot and aluminum ingot are higher than 1 150K, part of aluminum reacts with oxygen in the air to generate α-al2o 3. This crystalline chemical property of alumina is inert, which plays the role of barrier and isolation. When the temperature is lower than 1 150K, it is born in B-Al2O3, which reacts with acid and cannot protect the magnesium-aluminum alloy inside. The content of magnesium and aluminum in standard magnesium-aluminum alloy is about 50% respectively. The content of active aluminum has a great influence on the safety production and product quality of fireworks. However, most enterprises that produce magnesium-aluminum alloys are private enterprises. In recent years, aluminum ingots are more expensive than magnesium ingots, driven by interests, and most of them are not produced according to national standards. At present, the aluminum content in magnesium-aluminum alloy powder is generally below 50%, and some aluminum content is as low as 40%. With the increase of magnesium content, the performance of magnesium-aluminum alloy is close to that of magnesium powder, and the impact sensitivity and friction sensitivity of initiating explosive device are increased, which makes initiating explosive device more sensitive, thus increasing hidden dangers. We can use the following chemical mechanism to test the aluminum content in magnesium-aluminum alloy. Al-based alloy. The main alloying elements are copper, silicon, magnesium, zinc and manganese, and the secondary alloying elements are nickel, iron, titanium, chromium and lithium. Aluminum alloy has low density, but its strength is relatively high, close to or higher than that of high-quality steel. Good plasticity, can be processed into various profiles, and has excellent electrical conductivity, thermal conductivity and corrosion resistance. It is widely used in industry, and its usage is second only to steel. Aluminum alloys are divided into two categories: cast aluminum alloys, which are used as cast; Deformed aluminum alloy can withstand pressure processing, and its mechanical properties are higher than as-cast. Can be processed into various forms and specifications of aluminum alloy materials. Mainly used for manufacturing aviation equipment, daily necessities, building doors and windows, etc. Aluminum alloys can be divided into wrought aluminum alloys and cast aluminum alloys according to processing methods. Wrought aluminum alloys can be divided into non-heat treatment strengthened aluminum alloys and heat treatment strengthened aluminum alloys. Non-heat treatment strengthening type can not improve mechanical properties through heat treatment, but only through cold working deformation, mainly including high-purity aluminum, industrial high-purity aluminum, industrial pure aluminum and rust-proof aluminum. Heat-treatable strengthened aluminum alloys can improve their mechanical properties by means of heat treatment such as quenching and aging, which can be divided into hard aluminum, forged aluminum, superhard aluminum and special aluminum alloys. Some aluminum alloys can obtain good mechanical properties, physical properties and corrosion resistance through heat treatment. According to chemical composition, cast aluminum alloys can be divided into Al-Si alloy, Al-Cu alloy, Al-Mg alloy, Al-Zn alloy and Al-RE alloy. Among them, the Al-Si alloy is a simple Al-Si alloy (which can not be strengthened by heat treatment, with low mechanical properties and good castability), and the special Al-Si alloy (which can be strengthened by heat treatment, with high mechanical properties and good castability) is the abbreviation of plastic steel profile, and its main chemical composition is PVC, so it is also called PVC profile. This is a new building material that has been widely used in recent years. The material has excellent performance, convenient processing and wide application. Because of its excellent physical properties such as rigidity, elasticity, corrosion resistance and aging resistance, it is usually used as a good substitute for non-ferrous metals such as copper, zinc and aluminum. In building construction, it is mainly used for pushing and pulling, horizontally opening doors and windows, guardrails, pipes and ceiling materials. Advantages: affordable, good thermal insulation and sound insulation. ◆ The most popular and economical: Conch plastic steel and Shide plastic steel, national inspection-free products with guaranteed quality, are very good brands promoted in China. And the price is relatively economical, but the market is full of fake conch and Shide. How long should consumers be careful? ◆ Moderate price: LG Haojiaxi plastic steel. LG likes its performance characteristics. Good decorative effect and the like. It is a product of LG Chemical in the field of building materials, imported technology and produced in Tianjin. In the market, both the formula of profiles and the design of cavities are better than those of Conch and Shide, and their prices are slightly higher than those of Conch doors and windows and Shide doors and windows. ◆ More upscale: Kemeiling plastic-steel profile is the highest level in the industry in terms of wind pressure resistance, air tightness, water tightness and profile structure. As an expert in door and window system in Germany, Kemeiling can provide professional door and window solutions and achieve high-quality buildings, whether it is a door and window processing enterprise or a real estate user. To sum up, you can choose according to your own needs. References:

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