Production process of sintered corundum

Sintered corundum, as a high-performance refractory material, is widely used in steel smelting, ceramic manufacturing, abrasives and electronic industries. Its excellent high temperature resistance, corrosion resistance and mechanical strength make it an indispensable key material in industrial production. This article will explore the production process of sintered corundum in depth, from raw material selection, preparation process, sintering process to post-processing and quality control, and comprehensively analyze its production process.

1. Raw material selection and preparation

The production of sintered corundum first depends on high-quality raw materials. The main raw material is industrial alumina (Al₂O₃), and its purity must reach more than 99% to ensure the performance of the final product. In addition, depending on the use of the product, a small amount of additives such as magnesium oxide (MgO) and silicon oxide (SiO₂) may be added to adjust the physical and chemical properties of the material.

The pretreatment of raw materials is an important link in the production process. Alumina powder needs to undergo strict screening, impurity removal and drying to ensure uniform particle size distribution and reduce defect formation during sintering. At the same time, the additives also need to be accurately measured and evenly mixed in the alumina powder to achieve the desired modification effect.

2. Preparation process

1. Molding

Molding is the process of making the pretreated powder raw materials into a blank with a specific shape and size. Common molding methods include compression molding, isostatic pressing and injection molding. Compression molding is widely used because of its simple equipment and convenient operation, but it is necessary to control the pressure to avoid cracks or uneven density inside the blank. Isostatic pressing can transmit pressure more evenly and is suitable for preparing large or complex shapes.

2. Drying

The blank after molding contains a high amount of water, and it needs to be dried to remove excess water to prevent cracking due to excessive evaporation of water during the sintering process. The drying process requires strict control of temperature and time to avoid deformation or cracking of the blank due to excessive drying.

3. Sintering process

Sintering is the core link in the production of sintered corundum and a key factor in determining product performance. The sintering process is carried out at high temperature, and the solid phase reaction forms a close bond between the particles, which improves the density and strength of the material.

1. Heating stage

The heating stage needs to be carried out slowly to avoid thermal stress inside the green body due to excessive temperature difference, which leads to cracking. At the same time, the atmosphere needs to be controlled during the heating process to ensure that the oxygen content in the sintering environment is moderate to avoid the reduction of alumina.

2. Sintering stage

The sintering temperature is a key parameter in the sintering process, which directly affects the density, phase composition and performance of the product. Generally speaking, the sintering temperature needs to be higher than the melting point of alumina, but too high a temperature will cause grain growth and affect the strength and toughness of the material. Therefore, determining the optimal sintering temperature is an important task in the sintering process.

3. Cooling stage

After sintering, slow cooling is required to prevent thermal stress caused by rapid cooling from causing product cracking. Control of cooling rate is also an important link to ensure product quality.

4. Post-processing and quality control

1. Post-processing

Sintered corundum products may need some post-processing, such as cutting, grinding, polishing, etc., to meet the size and surface quality requirements of the final product. In addition, surface coating treatment may also be performed to improve the corrosion resistance and wear resistance of the product.

2. Quality control

Quality control runs through the entire production process. From the entry of raw materials to the exit of products, each process requires strict quality inspection. It mainly includes the purity and particle size inspection of raw materials, the density and size inspection of green bodies, the density, phase composition and performance inspection of sintered products, etc. Through strict quality control, the stability and reliability of sintered corundum products are ensured.

5. Environmental protection and sustainable development

With the enhancement of environmental awareness, the production of sintered corundum also needs to pay attention to environmental protection and sustainable development. Waste gas, wastewater and solid waste generated during the production process need to be properly handled to reduce pollution to the environment. At the same time, promote the use of clean energy and energy-saving technologies to reduce energy consumption and emissions in the production process and achieve green production.

In summary, the production process of sintered corundum is a complex and delicate process, involving multiple links such as raw material selection, preparation process, sintering process, post-processing and quality control. By continuously optimizing the production process and improving product quality and production efficiency, sintered corundum will play an important role in more fields and contribute to industrial development.