What is Abrasive Grain Technology?
It is crucial to select the appropriate abrasive mineral for each material during the grinding process. This not only prevents surface damage but also enhances the efficiency of the grinding operation, minimizing the overall time required. However, these minerals in abrasive grain technology do not possess the same hardness, leading to variations in their performance during grinding operations. Apart from structural differences, each mineral also exhibits unique characteristics, such as resistance to scratching, impact, and self-sharpening.
For instance, aluminum oxide (AO) is widely used for materials like metal, wood, and plastic, making it the most versatile mineral for various applications. On the other hand, silicon carbide (SiC) is commonly utilized for finishing applications and is suitable for hard materials like glass, minerals, ceramics, rocks, and even grinding iron. Additionally, zirconia alumina (ZA), ceramic abrasives (CER), and bonded abrasives are widely employed in coarse processing, grinding, and surface polishing applications.
VSM offers a comprehensive range of abrasive grain technology
The performance of abrasives is influenced by the hardness, size, and shape of the abrasive particles. Not all abrasives have the same hardness, and higher hardness abrasives tend to be more effective in rapidly removing material from surfaces and producing a finer finish. Larger abrasive particles also generate higher impact forces. The range of abrasives is vast, ranging from softer abrasives used in household cleaning agents to more durable gemstone abrasives, and even the toughest material, diamond, which is essential for manufacturing precision products. Among them, zirconia alumina, bonded abrasives, ceramic abrasives, silicon carbide, and aluminum oxide are widely employed to meet various grinding and polishing needs.
1. Zirconia Alumina Abrasive:
Zirconia alumina is a type of alumina that contains 10% to 40% zirconium dioxide (ZrO2). It is produced by melting raw materials, including aluminum oxide, and subjecting them to temperatures above 2000°C in an arc furnace. Through the melting and subsequent crystallization process, a eutectic composite consisting of α-Al2O3 and ZrO2 is formed, with the secondary phase being monoclinic zirconia and a small amount of glass phase. Zirconia alumina exhibits better toughness and lower hardness compared to pure aluminum oxide and typically appears as a gray-brown color. Depending on the ZrO2 content, it is classified as either 25% zirconia alumina (ZrO225%) or 40% zirconia alumina (ZrO240%).
| Applications | Zirconia alumina is well-suited for various applications involving cast steel, alloy steel, and high-speed steel. It is particularly suitable for machining titanium alloys, heat-resistant alloys, high-vanadium steel, and stainless steel. It is commonly used for both manual and machine grinding due to its ability to withstand heavy pressure and perform well in wet grinding conditions. |
2. Bonded Abrasives:
The bulk density of abrasive grains, particle shape, and composition are important parameters that collectively reflect the physical properties of bonded abrasives. It is closely related to the formability, product strength, and porosity of the abrasive tool, directly impacting its grinding performance. It is also an essential technical data for calculating the volume of storage bins. Therefore, according to the JB/T7984.2-1995 standard, each batch of abrasive should have its bulk density indicated on the packaging. Sandcloth, which is made by bonding bonded abrasives to a cloth substrate using organic polymer binders and related materials, is known as a bonded abrasive sandcloth. Converting bonded abrasive sandcloth into sanding belts results in bonded abrasive belts.
| Applications | Medium pressure wet grinding with longer lifespan is suitable for machine grinding, high-speed steel, high-temperature tempered steel, titanium alloys, and safety glass. |
Bonded abrasive belts, as a highly competitive high-tech product in the market, are particularly suitable for surface grinding, polishing, and brushing processes of titanium alloys, stainless steel, aluminum alloys, carbon steel castings, galvanized work pieces, heat-resistant steel, nickel-chromium alloys, and high-low alloy steels. Their market applications cover a wide range of specialty steel work pieces, such as metal cans, heads, pipes, hydraulic cylinders, engine cylinders, impellers, water tanks, sanitary ware, medical devices, and golf equipment, for polishing and grinding. They are also used in the grinding and polishing of cold-rolled steel sheets and strips, stainless steel wire drawing, steel coils, and automotive body polishing, among other fields.
3.Ceramic Abrasive:
Ceramic abrasives are a new type of abrasive with a micro crystalline structure that is obtained through the gel sintering method. They are not produced through traditional smelting methods but are made using fine particles of Al2O3 or SiC, typically below 5 μm. In the presence of acid, a gel is formed by adding certain oxides to the raw materials, which is then shaped into particles. The raw material requirements are strict, with sodium oxide content typically below 5%.
Ceramic abrasives are hard and tough, and their refined crystal structure allows for the orderly shedding of abrasive layers, resulting in systematic self-sharpening and maintaining the sharpness of the entire abrasive grain, leading to excellent processing results. Ceramic abrasives have two significant characteristics: high cutting capacity and the ability to perform cold grinding. Ceramic abrasives produced by vitrified bond have qualities such as “micro hardness of 2020HV0.2” and “grain size of 196.3 nanometers.” They exhibit exceptional sharpness, strong self-sharpening ability, and do not cause thermal damage to the work piece.
| Applications | Ceramic abrasives can be processed into various shapes such as spheres, cylinders, grains, and edges. They are formed through advanced processes and scientific processing of micro-powdered mullite. Ceramic abrasives have high Mohs hardness and exhibit high efficiency in ball milling, making them suitable as high-quality grinding media for various grinding machinery. They also have excellent corrosion resistance and a low coefficient of thermal expansion. |
4.Silicon carbide Abrasive:
Silicon carbide, commonly known as carborundum or SiC, is a ceramic compound consisting of silicon and carbon atoms. It is highly renowned for its extreme hardness, ranking second only to diamond as the hardest material known. Silicon carbide exists naturally in the form of a rare mineral called moissanite. Since 1893, silicon carbide powder has been widely used as an abrasive material.
By sintering silicon carbide powder, one can obtain hard ceramic silicon carbide particles. These particles can be utilized in various applications that require high durability, such as automotive brake pads, clutches, and bulletproof vests. Silicon carbide’s exceptional hardness and resistance to wear make it an ideal choice for demanding materials.
Overall, silicon carbide is a versatile compound with remarkable properties, including high hardness, wear resistance, and thermal stability. It finds extensive applications in industries ranging from abrasives and ceramics to electronics and aerospace.
| Applications | Silicon carbide has a high hardness, with a Mohs hardness of approximately 9.2-9.5, making it extremely resistant to wear. It exhibits excellent wear resistance, allowing it to withstand abrasive forces and maintain its integrity for extended periods. |
5.Aluminum oxide Abrasive:
Aluminum oxide, also known as alumina, exhibits a high surface hardness and excellent scratch resistance, making it suitable for use as a hard and wear-resistant coating. Its surface oxide film acts as an insulator, providing protection against corrosion. This oxide film also has the ability to retain selected oils within its pores, providing lubrication and wear resistance. As a result, aluminum oxide coatings also possess anti-static properties.
| Applications | It is suitable for various applications such as anti-static workstations on assembly lines, fire-resistant frames for conveyor belts, and non-toxic environments. It is particularly well-suited for enclosed spaces like clean rooms due to its high fire resistance. It does not ignite at temperatures up to 600 degrees Celsius, meeting fire safety and environmental requirements. Additionally, it exhibits strong resistance to staining, does not leave fingerprints, is easy to clean, and does not produce corrosive spots. |
Grinding abrasives exist in various particle sizes and are incorporated into different grinding and polishing tools, such as sandpaper, grinding wheels, and so on. These particles range in size from visible grains on coarse sandpaper to sizes as fine as flowing liquids. The reason for the wide variety of grinding tools lies in the fact that the only challenge in grinding is the shape of the object being worked on. Since the objects requiring grinding and polishing can have various shapes, a range of grinding tools is developed to correspond to the shapes of the objects. This is why there are so many different types of grinding tools available.
References:
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