Electrothermal materials can convert electrical energy into thermal energy and are used to manufacture resistance heating elements, which are widely used in industrial and civilian equipment. In the field of high-temperature processing, operations under extreme working conditions increase constantly, making the selection of electrothermal materials critical. This article delves into the basic aspects of silicon carbon rods: their types, properties, materials used in their manufacture, application benefits, and application analysis.
1. Types and Characteristics of Electrothermal Materials
Electrothermal materials can be roughly divided into two types: metal and non-metal.
Metal electrothermal materials mainly include nickel-based alloys (such as nickel-chromium wire Ni-Cr) and iron-based alloys (such as iron-chromium-aluminum wire Fe-Cr-Al).
Non-metallic electrothermal materials include silicon carbon rods, silicon-molybdenum rods, PTC electrothermal elements, MoSi2, etc.
· Metal electrothermal materials
Since metal electrothermal materials have good thermal conductivity and electrical conductivity, and are easy to be molded, widely used as heating elements for the electric furnace in traditional industries and household appliances.
Nickel-chromium alloys have a maximum heating temperature of 1150°C, and iron-chromium alloys 1400°C. Generally, when the operating temperature exceeds 1000°C, there will be problems such as volatilization, deformation, and even melting.
Additionally, the oxidation rate of metal heating elements is relatively fast, and it is difficult to ensure stability and long-term effectiveness in continuous use. Moreover, the resistance rate of metal heating elements will increase at high temperatures, which reduces the thermal conductivity at high temperatures.
· Non-metallic electrothermal materials
Non-metallic electrothermal materials have the characteristics of high temperature resistance, good thermal stability, corrosion resistance, oxidation resistance, high electric heat conversion rate, and excellent mechanical properties.
Therefore, non-metallic electrothermal materials are stabler than metal materials in extreme high-temperature and corrosive industrial environments, seeing wide applications in electric furnaces and experimental electric furnaces in high-temperature industries as well as in aerospace, biomedicine, automotive and other fields.
2. Carbon Silicon Materials and Advantages of Silicon Carbide Rods
Silicon carbide (SiC) is a new inorganic non-metallic material produced by smelting silica sand and carbon-containing raw materials at a high temperature. Artificially synthesized silicon carbide was accidentally discovered by American scientist Edison in 1891 during an experiment.
Silicon carbide has many advantages, including high hardness, high thermal conductivity, high chemical stability, high thermal stability, and semiconductor properties. It has been widely used in various fields such as electronic devices, abrasives and cutting tools, refractory materials, aerospace, automotive industry, and other equipment.
Carbon silicon rods are made of high-purity green hexagonal silicon carbide as the main raw material, which is precisely formulated and processed into the desired shape, then fired at a temperature of 2200°C to form a rod-shaped or tube-shaped non-metallic high-temperature electric heating component.
The melting point of silicon carbide rods is very high, with the working temperature in an oxidizing environment able to reach 1,450°C, and it can operate continuously and stably for 2000 hours.
In addition to the characteristics of high temperature stability and strong oxidation resistance, silicon carbide rods also have the advantages of high wear resistance, excellent corrosion resistance, rapid heating, and easy installation and use.
Additionally, at certain temperatures, the resistivity of silicon carbide rods decreases significantly with an increase in temperature, thereby providing more efficient thermal conductivity than metal components at high temperatures.
In addition to serving as the core electric heating component for tunnel kilns, roller kilns, glass melting furnaces, vacuum furnaces and other various heating devices, silicon carbon rods can also work with advanced automated electronic control systems to achieve precise constant temperature control, and perform curve-type automatic temperature adjustment according to specific production process requirements.
3. Application Analysis of Silicon Carbide Rods
Although silicon carbon rods have many advantages that metal electric heating elements do not have, their use is limited due to their higher price than metal thermoelectric materials which are generally used when the operating temperature is below 1000°C. Silicon carbide rods are more commonly used in extreme working environments where metal thermoelectric materials cannot qualify.
Applications of Silicon Carbide Rods
· Industrial Furnace Equipment: Silicon carbide rods can be used as heating elements, hearths, and casting molds for various electric furnaces in industries such as metallurgy and manufacturing.
· The electronics industry: During the heat treatment process of materials such as semiconductors, silicon carbide rods can provide a precisely controlled high-temperature environment to meet stringent technical requirements.
· Preparation of magnetic materials: Silicon carbide rods are often used for sintering and annealing of magnetic materials, with their extremely high temperature stability ensuring the performance and quality of magnetic materials.
· The ceramics and glass manufacturing industry: silicon carbide rods can effectively maintain the constant high temperature required during preparation, ensuring uniform heating of the blank, thus improving the quality of the product.
· Scientific research: Silicon carbide rods are well suited for experimental environments that require rigorous control of temperature changes.
Furthermore, silicon carbide rods have shown great potential in the applications in fields such as medicine, food, environmental monitoring due to their excellent performance in chemical, mechanical, optical, and other properties.
4. Summary
In high-temperature industrial processes, the continuous operation of furnaces is particularly dependent on long-life materials to minimize the downtime and maximize the return on investment. Therefore, thermoelectric materials need to be highly specialized and have excellent performance to match various furnace types. Silicon carbide rods are therefore the ideal choice for high-temperature thermoelectric materials. With the continuous growth of the global economy and the advancement of the industrialization process, the application market of silicon carbon rods is steadily expanding.
