Application and Development of Ceramics in Automotive Coating

Release Time:

2013-01-31 16:53

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In recent years, ceramic thin-film spraying technology, widely used in aerospace technology, has begun to be applied in automobiles. The advantages of this technology include excellent heat insulation, the ability to withstand high temperatures and high pressure, mature processes, and stable quality. To achieve the goal of low heat dissipation, ceramic spraying can be applied to engine combustion chamber components, such as zirconia sprayed on the piston top and zirconia sprayed on the cylinder liner. Engines treated in this way can reduce heat loss, lighten the engine's own weight, reduce engine size, and decrease fuel consumption. Classification and characteristics of ceramics The performance of ceramics is determined by two factors. The first is the material structure, mainly the nature of chemical bonds and

　　In recent years, ceramic thin-film spraying technology, widely used in aerospace technology, has begun to be applied in automobiles. The advantages of this technology include good heat insulation, the ability to withstand high temperatures and high pressure, mature processes, and stable quality. To achieve low heat dissipation, ceramic spraying can be applied to engine combustion chamber components, such as zirconia sprayed on piston tops and zirconia sprayed on cylinder liners. Engines treated this way can reduce heat loss, lighten the engine's own weight, reduce engine size, and decrease fuel consumption.

　　Classification and Characteristics of Ceramics

　　The performance of ceramics is determined by two factors. The first is the material structure, mainly the nature of chemical bonds and crystal structure. These determine the properties of ceramic materials, such as high-temperature resistance, semiconductivity, and insulation. The second is the microstructure, including distribution, grain size, shape, pore size and distribution, impurities, and defects.

　　Common Ceramics

　　Common ceramics are made from clay, feldspar, and quartz as raw materials, processed and sintered. These ceramics are hard in texture, do not oxidize or rust, are corrosion-resistant, non-conductive, can withstand certain high temperatures, have good processability, and are low cost, but have relatively low strength. Generally, their maximum operating temperature does not exceed 1200 degrees Celsius. These ceramics are produced in large quantities, come in many varieties, and are widely used in electrical, chemical, and other industries.

　　Alumina Ceramics

　　Alumina ceramics, also known as high-alumina ceramics, mainly consist of alumina and silica. They have high strength, high hardness, corrosion resistance, good insulation, and can withstand temperatures up to 1600 degrees Celsius. However, they are brittle, have poor shock resistance, complex processing, and high cost. The excellent high-temperature and dielectric properties of alumina ceramics make them suitable for manufacturing engine spark plugs; their good wear resistance ensures pistons can be machined to very high precision and surface finish.

　　Silicon Carbide Ceramics

　　Silicon carbide ceramics are made from silicon carbide powder using powder metallurgy through reaction sintering or hot pressing sintering processes. Their main features are high strength at high temperatures, good thermal stability, and excellent wear and creep resistance. They are suitable for parts such as nozzles for metal casting, thermocouple sheaths, gas turbine blades, and bearings. Due to their high thermal conductivity, they are also suitable as heat exchanger materials under high-temperature conditions and can be used to make various pump seals.

　　Silicon Nitride Ceramics

　　Silicon nitride ceramics have abundant raw materials and good processability, allowing low-cost production of parts with precise dimensions, especially complex shapes, with a higher yield than other ceramic materials. Silicon nitride ceramics have good resistance to thermal shock and high hardness, second only to diamond and boron nitride. Using silicon nitride ceramic materials to manufacture engines, with operating temperatures raised to 1370 degrees Celsius, can improve engine efficiency by 30%. At the same time, the higher temperature allows fuel to burn fully, significantly reducing pollutants in exhaust gases, which not only lowers energy consumption but also reduces environmental pollution.

　　Other Ceramic Materials

　　There are many types of ceramic materials, each with unique features, capable of being made into various functional components. Lithium oxide ceramics are high-temperature materials; talc ceramics are high-frequency insulating materials; thorium oxide ceramics are dielectric materials; barium titanate ceramics are optoelectronic materials; borides, nitrides, and silicides are ultra-high-temperature metal ceramics. Ferrite ceramics are used for permanent magnets, memory magnets, and magnetic heads; rare earth cobalt ceramics are storage materials; semiconductor ceramics are used for sensitive components and solar cells.

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Development Trends of Silicon Carbide Products

Cubic nanometer silicon carbide micropowder, also known as β-silicon carbide, β-SiC is close to diamond, with surface finish and polishing performance far superior to white corundum and α-SiC (black silicon carbide and green silicon carbide); at temperatures above 1600°C, β-SiC still possesses ultra-high strength; β-SiC has several times higher electrical conductivity than α-SiC; β-SiC has excellent thermal conductivity and low expansion coefficient, resulting in minimal thermal stress during heating and cooling; β-SiC is a low-temperature crystal form and can undergo a phase transformation above 1800°C; in terms of specific gravity, β-SiC is half that of most alloys, 40% that of steel, and roughly the same as aluminum.

Cubic Nanometer Silicon Carbide Micropowder

Basic Knowledge of Silicon Carbide

Silicon carbide includes black silicon carbide and green silicon carbide. Among them, black silicon carbide is made primarily from quartz sand, petroleum coke, and high-quality silica through high-temperature smelting in a resistance furnace. Its hardness lies between corundum and diamond, with mechanical strength higher than corundum, and it is brittle and sharp.

Application and Development of Ceramics in Automotive Coating

Development Trends of Silicon Carbide Products

Silicon carbide products are increasingly used in petroleum, chemical, automotive, machinery, and aerospace fields. There is an urgent need to continuously improve manufacturing technology and reduce production costs while enhancing the performance of silicon carbide products. Achieving low-temperature sintering of silicon carbide products can significantly reduce energy consumption, markedly lower production costs, and promote the industrialization of silicon carbide products.