Application and performance characteristics of composite aluminum grease
author: Leila
2025-05-12
1. Basic concept of aluminum complex grease:
Compared with ordinary aluminum complex grease, aluminum complex grease has many advantages in performance. Since its introduction in the 1960s, the development of aluminum complex grease has been relatively slow compared with lithium complex grease, mainly due to the high requirements for production process and production equipment, and the slow breakthrough of some key performance. Now, with the development of some technical patents, the performance of aluminum complex grease has been greatly improved in water resistance, high temperature resistance and shear stability. Aluminum complex grease has also become a multi-functional grease with many performance advantages.
Like other types of grease, most of the components of aluminum complex grease are base oil, which is thickened with aluminum complex soap thickener, so it is called aluminum complex grease. Synthetic aluminum complex grease uses synthetic oil as base oil, and general base oil is mineral base oil. According to the different additive formulas, aluminum complex grease has extreme pressure aluminum complex grease, anti-oxidation and anti-rust aluminum complex grease and other types. For example, synthetic extreme pressure aluminum-based grease indicates that the thickener type is a composite aluminum-based thickener, the base oil uses synthetic oil, and the additive uses extrusion additives (EP).
2. Common uses of composite aluminum-based grease:
1) Lubrication of automobile wheel hub bearings: Under normal vehicle speeds and road conditions, the load and temperature of the wheel hub bearings are not high, mainly due to the heat generated by the friction of the bearings. However, when braking downhill, in mountainous areas with poor road conditions, or on bumpy roads, or when the vehicle is braking at too fast a speed, the friction heat of the brake drum will be transferred to the bearings, adding additional temperature to the wheel hub bearings, so the grease needs to have excellent high temperature performance. The high temperatures and large temperature differences that may be experienced, if general greases are not adapted to high temperature changes, will cause leakage. Common types of automobile wheel hub bearings are lithium-based grease, composite lithium-based grease, polyurea grease, and composite aluminum-based grease. When using automobile wheel hub grease, it should be noted that greases of different consistency grades and different types cannot be mixed.
2) Lubrication of mechanical parts in the manufacturing industry: composite aluminum-based grease can be used for lubrication of machine parts, and composite aluminum-based grease has good water resistance. The water resistance of grease is very important in industrial production. In addition, composite aluminum-based thickeners are also suitable for the preparation of food-grade greases. They can be used with food-grade additives and base oils to make food-grade composite aluminum-based greases.
3) Lubrication of iron and steel metallurgical equipment: Equipment in the iron and steel metallurgical industry generally faces high temperature and humid working conditions. Extreme pressure composite aluminum-based grease is suitable for the requirements of such working conditions, because composite aluminum-based grease has good low-temperature pumpability, centralized lubrication is easy to transmit, and also has the advantages of high temperature resistance and good water resistance. In addition, composite aluminum-based grease also has a special property: high-temperature reversibility. That is, after cooling down from high temperature, the consistency can remain stable. This is not available in other greases, so composite aluminum-based grease can maintain a relatively stable consistency characteristic in temperature changes, coupled with good water resistance, so that composite aluminum-based grease has good leakage prevention ability, suitable for the lubrication of iron and steel metallurgical equipment.
4) Marine trailers: Since composite aluminum grease has good water resistance, it is very suitable for marine trailers to use composite aluminum grease, which can be used for lubrication of trailer wheel hub bearings and trailer hitches.
5) Rubber and plastic industry: Composite aluminum grease can be used for internal mixer lubrication to meet the working conditions of internal mixers with high temperature, humidity and contact with corrosive gases.
6) Textile machinery: Composite aluminum grease can be used almost everywhere in the textile industry where grease is needed. Composite aluminum grease can adhere firmly to the bearings, and its good waterproofness can play a better sealing role and reduce the possibility of grease contamination of the fabric.
7) Agricultural machinery and engineering machinery: On these machines, composite aluminum can be used as a general grease. Composite aluminum grease can be used in most places where grease is needed, and it has good anti-rust and water resistance.
3. Advantages of composite aluminum grease:
1) Waterproofness: As long as the formula is reasonable, composite aluminum grease has excellent water resistance. Whether in bearings or on the surface of flat parts, composite aluminum grease shows good water resistance. This is very important because water resistance is very important in industrial applications. Although there are differences in the water resistance of different composite aluminum greases, in general, the water resistance of composite aluminum grease is the best among general greases. After contact with water, the shear stability of composite aluminum grease will be slightly reduced, but not very serious.
2) Heat resistance: Composite aluminum grease has good high temperature resistance, and the dropping point is generally between 232℃ and 246℃. Therefore, the use temperature is higher than that of general lithium grease (not composite lithium grease).
For high temperature grease, high dropping point ≠ good high temperature performance, and high dropping point is only a necessary condition. At high temperature, grease must also withstand mechanical and high temperature shear. At high temperature, grease must also have good thermal stability and good oxidation resistance. If the temperature fluctuates, the grease will be challenged even more. Some high-temperature greases may have unstable performance during the alternating high and low temperature process. The factors that affect the high-temperature properties of grease are of course determined by the base oil, thickener, and additives of the grease, but from the perspective of the thickener alone, the composite aluminum-based grease has excellent high-temperature properties. Because the composite aluminum-based thickener not only has a high dropping point, but also has special high-temperature reversibility. High-temperature reversibility means that after the use part is heated and cooled, the composite aluminum-based grease can still restore a good gel structure, which is an advantage that lithium-based grease does not have.
3) Low-temperature pumpability: The soap fibers of the composite aluminum-based grease are thin and short, and the thickening ability of mineral oil is strong, so the soap dosage is small, the oil content is high, and it is easy to pump at low temperatures, so it is also suitable for centralized lubrication systems.
4. Disadvantages of composite aluminum grease:
1) The preparation process of composite aluminum soap is relatively complicated. Since the 1970s, foreign composite aluminum grease manufacturers have used isopropyl aluminum trimer as raw material to produce composite aluminum grease, gradually replacing the production method of isopropyl alcohol to produce composite aluminum grease. However, the preparation process of isopropyl aluminum trimer is relatively complicated, so the production cost of composite aluminum grease is relatively high.
2) Composite aluminum soap has a strong thickening ability for mineral oil, but has a poor thickening ability for synthetic oils such as silicone oil, ester oil, PAG, etc., and even does not form grease.
3) Compared with composite lithium grease and urea grease, the bearing operation life of composite aluminum grease is not long.
2) Composite aluminum soap has a strong thickening ability for mineral oil, but has a poor thickening ability for synthetic oils such as silicone oil, ester oil, PAG, etc., and even does not form grease.
3) Compared with composite lithium grease and urea grease, the bearing operation life of composite aluminum grease is not long.
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