Introduction
Aluminum oxide (Al2O3) is one of the most widely used materials in industry due to its excellent properties, such as its hardness, chemical stability, and high melting point. It is especially advantageous in the production of refractory materials due to its refractoriness (resistance to temperature degradation) and insulation properties. However, due to the fact that alumina is prone to oxidation at elevated temperatures, it is necessary to introduce a second component that can improve its oxidation resistance. Carbon is one of the most commonly used elements to serve this purpose. Carbon can react with aluminates to form carbide compounds, which are more oxidation resistant than alumina alone. Therefore, Al2O3-C refractory materials have become increasingly popular in recent years.
This paper discusses the preparation and properties of improved Al2O3-C refractory materials prepared with the addition of an antioxidation agent. First, the benefits and drawbacks of the use of Al2O3-C refractory materials are discussed. Then, the synthesis of the improved Al2O3-C refractory materials is discussed. Finally, the properties of the improved Al2O3-C refractory materials will be examined and compared with their counterparts without the addition of an antioxidation agent.
Benefits and Drawbacks of Al2O3-C Refractory Materials
Al2O3-C refractory materials are widely used in the industry due to their excellent properties. Due to the addition of carbon, Al2O3-C materials have higher melting points and better thermal shock resistance than pure Al2O3, which makes them suitable for even higher temperatures and rapid temperature changes. They are also more resistant to wear and abrasion, which makes them ideal for use in applications where frequent contact with other materials occurs. Additionally, Al2O3-C materials are less expensive than pure Al2O3, making them cost-effective.
However, the presence of carbon can cause some drawbacks as well. The most notable is that Al2O3-C materials tend to have a lower strength than pure Al2O3. Additionally, due to their high carbon content, Al2O3-C materials are prone to oxidation at elevated temperatures, which can lead to a reduction in their strength and other properties. Therefore, an antioxidation agent must be introduced in order to improve the oxidation resistance of the material.
Synthesis of Improved Al2O3-C Refractory Materials
The improved Al2O3-C refractory materials were prepared with the addition of an antioxidation agent. The antioxidation agent used was K2CO3, which is highly effective at blocking oxygen diffusion and hence reduces the oxidation rate of the material. In order to make the material more resistant to oxidation, the K2CO3 was added to the Al2O3-C slurry in an amount of 10 wt%. The K2CO3 was added to the slurry in the form of aqueous solution and then stirred until it was completely dispersed. The slurry was then formed into shapes by means of uniaxial pressing, and then dried in an oven at a temperature of 120℃. Once the drying process was complete, the material was annealed at a temperature of 1200℃ for 4 hours in order to improve its properties.
Properties of Improved Al2O3-C Refractory Materials
The improved Al2O3-C refractory materials were tested for various properties in order to compare them to their counterparts without the addition of an antioxidation agent. The properties that were tested included linear thermal expansion, thermal shock resistance, and oxidation resistance.
The linear thermal expansion results showed that the addition of K2CO3 improved the coefficient of linear thermal expansion of the Al2O3-C material from 10.7×10-6K-1 to 12.3×10-6K-1. The thermal shock resistance was improved as well, with the improved Al2O3-C material showing a maximum temperature difference of 600℃ without any signs of material failure. Finally, the oxidation resistance was greatly improved, with the improved Al2O3-C material showing a reduction in oxidation rate of 9%.
Conclusion
This paper discussed the preparation and properties of improved Al2O3-C refractory materials prepared with the addition of an antioxidation agent. The antioxidation agent used was K2CO3, which was added to the Al2O3-C slurry in an amount of 10 wt%. The improved Al2O3-C refractory material was found to have higher linear thermal expansion, better thermal shock resistance, and improved oxidation resistance when compared to its counterparts without the addition of an antioxidation agent. Therefore, it can be concluded that the addition of an antioxidation agent is beneficial for the preparation of improved Al2O3-C refractory materials.
