Silicon carbide is one of the hardest materials available, second only to diamond and cubic boron nitride. Due to this property, silicon carbide is widely used in high performance applications like machining/cutting tools, armor materials and electronic components.
Budget constraints often play a factor in material selection decisions. This article compares alumina ceramics and silicon carbide materials and discusses their unique properties and applications.
Hardness
Silicon carbide ceramic is an inert material used in various applications that demand toughness, hardness and high temperature resistance, such as wear-resistant parts for their hardness; refractories for its strength at elevated temperatures; electronic components for thermal conductivity.
Friedrich Mohs (1873-1839), an internationally recognized mineralogist and geologist, developed the Mohs hardness scale as an objective way of quantifying materials’ ability to scratch one another. This scale provides mineral samples with easily understandable physical values which allow comparison of their ability to resist abrasion and impact resistance.
Alumina boasts an approximate hardness rating of 9 on the Mohs scale and is one of the hardest known materials, making it an excellent choice for applications involving abrasive forces, such as bearings and seals.
Alumina displays excellent mechanical strength, particularly its flexural properties. This quality makes alumina an invaluable material for use in ceramic abrasion-resistant products as it enables significant strain to be applied without cracking or breaking. Furthermore, its relative hardness and strong mechanical strength is offset by lower thermal conductivity than silicon carbide ceramics.
Thermal Conductivity
Silicon carbide (also referred to as carborundum) is a hard chemical compound of silicon and carbon that occurs naturally as the rare mineral moissanite and manufactured commercially since 1893 in powder and granular forms for use as an abrasive material. Silicon carbide ranks third-hardest material after diamond and sapphire for hardness; however, through sintering technology it can also create ceramic materials with superior wear resistance and thermal conductivity properties.
Silicon carbide ceramics offer unique properties that make it ideal for industrial applications requiring high heat tolerance and strength, such as applications involving applications up to 1400degC that demand hardness and strength, making it the strongest and most corrosion-resistant structural ceramic. Silicon carbide also makes an excellent abrasive that can be easily formed into sharp grits for grinding steel alloys such as brake pads – an example of how its full potential is utilized by consumer automobile manufacturers.
Other Fine Ceramics can meet a range of industrial needs. Aluminum nitride has excellent thermal conductivity and low coefficient of thermal expansion rates, making it the ideal choice for semiconductor packages needing to dissipate excess heat effectively. Zirconia blocks heat but comes at a relatively high cost; use must be carefully managed in order to prevent brittleness.
Electrical Properties
Silicon carbide (SiC) is an inert ceramic material widely used for mechanically demanding applications. As a hard and strong material that resists corrosion and heat, SiC can be easily molded to produce products such as wear-resistant parts, refractories and ceramics, electronic components as well as being deoxidized as part of an antioxidation treatment. Furthermore, SiC can even serve as a deoxidizer and high temperature resistant material in metalworking environments.
Silicon carbide possesses excellent electrical properties. It features low dielectric loss, making it suitable for applications involving high voltages or friction/compression loads, while its thermal conductivity makes it an excellent option for heat dissipation applications – a factor which explains why silicon carbide forms the basis of many advanced devices and systems, including light-emitting diodes (LEDs) and semiconductor electronics.
Silicon carbide boasts excellent electrical and thermal properties, as well as a low coefficient of expansion that provides exceptional resistance to thermal shock in environments with rapid temperature variations. This feature makes silicon carbide particularly well suited for applications where rapid temperature fluctuations exist.
Ceramic and silicon carbide have subtle but distinct differences, each offering its own benefits to engineers and manufacturers alike. Understanding these distinctions will allow engineers and manufacturers to choose a material best suited for their particular application based on hardness, chemical resistance and thermal conductivity criteria.
Corrosion Resistance
Silicon carbide ceramics exhibit exceptional chemical corrosion resistance at elevated temperatures, making them suitable for use in environments exposed to acids found in flue gas desulphurization plants and acid baths. Furthermore, they have great abrasion and impact resistance, making them suitable for components prone to physical wear such as spray nozzles and cyclone components.
Silicon carbide ceramics stand out as being highly thermal conductive materials, which allows them to rapidly dissipate heat when temperatures fluctuate rapidly – an invaluable quality in applications where temperatures may change rapidly. Their hardness also keeps them stable even under such harsh environments.
Silicon Carbide is one of the hardest materials known to man, second only to diamond and cubic boron nitride. Due to its chemical inertness, high strength, low coefficient of thermal expansion, and high hardness properties it has quickly found application across a range of industries such as ceramic ball bearings, valves, semiconductor materials gyroscopes measuring instruments aerospace.
SiC ceramics can be produced through various techniques, with reaction bonding being one of the most widely utilized approaches. This process involves infiltrating liquid or gaseous reactants into porous ceramic preforms to form dense objects. Furthermore, SiC can also be machined prior to sintering to facilitate creating complex shaped parts more quickly.