Ceramic Engineering is the technology of manufacturing and usage of ceramic materials. Many engineering applications benefit from ceramics characteristics as a material. The characteristics of ceramics have garnered attention from engineers across the world, including those in the fields: Electrical Engineering, Materials Engineering, Chemical Engineering, Mechanical Engineering, and many others. Highly regarded for being resistant to heat, ceramics can be used for many demanding tasks that other materials like Metal and Polymers can not.
Traditional ceramic raw materials include clay minerals such as kaolinite, more recent materials include aluminium oxide, more commonly known as alumina. The modern ceramic materials, which are classified as advanced ceramics, include silicon carbide and tungsten carbide. Both are valued for their abrasion resistance, and hence find use in applications such as the wear plates of crushing equipment in mining operations. Advanced ceramics are also used in the medicine, electrical and electronics industries.
Ceramic Engineers are found in a wide variety of manufacturing, research and educational fields. These include mining, aerospace, medicine, refinery, food industry, chemical industry, packaging science, electronics, industrial electricity, and transmission electricity.
Traditional ceramic raw materials include clay minerals such as kaolinite, more recent materials include aluminium oxide, more commonly known as alumina. The modern ceramic materials, which are classified as advanced ceramics, include silicon carbide and tungsten carbide. Both are valued for their abrasion resistance, and hence find use in applications such as the wear plates of crushing equipment in mining operations. Advanced ceramics are also used in the medicine, electrical and electronics industries.
Ceramic Engineers are found in a wide variety of manufacturing, research and educational fields. These include mining, aerospace, medicine, refinery, food industry, chemical industry, packaging science, electronics, industrial electricity, and transmission electricity.
The Ceramic Process
A general definition of a ceramic material could be: A ceramic is any inorganic crystalline oxide material. It is solid and inert. Ceramic materials are brittle, hard, strong in compression, weak in shearing and tension. They withstand chemical erosion that occur in an acidic or caustic environment. In many cases withstanding erosion from the acid and bases applied to it. Ceramics generally can withstand very high temperatures such as temperatures that range from 1,000°C to 1,600°C (1,800°F to 3,000°F). Exceptions include inorganic materials that do not have oxygen such silicon carbide. Glass by definition is not a ceramic because it is an amorphous solid (non-crystalline). However, glass involves several steps of the ceramic process and its mechanical properties behave similarly to ceramic materials.
The ceramic process generally follows this flow.
Milling→ Batching→ Mixing→ Forming→ Drying→ Firing→ Assembly→
Milling is the process by which materials are reduced from a larger size to a smaller size. Milling may involve breaking up cemented material, thus the individual particle retain their shape or pulverization which involves grinding the particles themselves to a smaller size. Pulverization is actually fracturing the grains and breaking them down.
Generally milling is done through mechanical means. The means include attrition which is particle to particle collision that results in agglomerate break up or particle shearing. Compression which is applying compressive forces that result in break-up or fracturing. Another means is impact which involves a milling media -or the particles themselves- that cause break up or fracturing.
Examples of equipment that achieve attrition milling is a planetary mill or an wet attrition mill, also called wet scrubber. A wet scrubber is a machine that has paddles in water turning in opposite direction causing two vortexes turning into each other. The material in the vortex collide and break up.
Equipment that achieve compression milling include a jaw crusher, roller crusher, and cone crushers.
Finally impact mills may include a ball mill with media that tumble and fracture material. Shaft impactors cause particle to particle attrition and compression which achieve size reduction.
Batching is the process of weighing the oxides according to recipes, and preparing them for mixing and drying.
Mixing occurs after batching and involve a variety of equipment such as dry mixing ribbon mixers (a type of cement mixer), Mueller mixers, and pug mills. Wet mixing generally involve the same equipment.
Forming is making the mixed material into shapes, ranging from toilet bowls to spark plug insulators. Forming can involve: 1) Extrusion, such as extruding "slugs" to make bricks 2) Pressing to make shaped parts. 3) Slip casting, as in making toilet bowls, wash basins and ornamentals like ceramic statues. Forming produces a "green" part, ready for drying. Green parts are soft, pliable, and over time will lose shape. Handling the green product will change its shape. For example, a green brick can be "squeezed", and after squeezing it will stay that way.
Drying is removing the water or binder from the formed material. Spray drying is widely used to prepare powder for pressing operations. Other dryers are tunnel dryers and periodic dryers. Controlled heat is applied in this two-stage process. First, heat removes water. This step needs careful control, as rapid heating causes cracks and surface defects. The dried part is smaller than the green part, and is brittle, necessitating careful handling, since a small impact will cause crumbling and breaking.
Firing is where the dried parts pass through a controlled heating process, and the oxides are chemically changed to cause sintering and bonding. The fired part will be smaller than the dried part.
Assembly This process is for parts that require additional subassembly parts. In the case of a spark plug, the electrode is put into the insulator. This step does not apply to all ceramic products.
The ceramic process generally follows this flow.
Milling→ Batching→ Mixing→ Forming→ Drying→ Firing→ Assembly→
Milling is the process by which materials are reduced from a larger size to a smaller size. Milling may involve breaking up cemented material, thus the individual particle retain their shape or pulverization which involves grinding the particles themselves to a smaller size. Pulverization is actually fracturing the grains and breaking them down.
Generally milling is done through mechanical means. The means include attrition which is particle to particle collision that results in agglomerate break up or particle shearing. Compression which is applying compressive forces that result in break-up or fracturing. Another means is impact which involves a milling media -or the particles themselves- that cause break up or fracturing.
Examples of equipment that achieve attrition milling is a planetary mill or an wet attrition mill, also called wet scrubber. A wet scrubber is a machine that has paddles in water turning in opposite direction causing two vortexes turning into each other. The material in the vortex collide and break up.
Equipment that achieve compression milling include a jaw crusher, roller crusher, and cone crushers.
Finally impact mills may include a ball mill with media that tumble and fracture material. Shaft impactors cause particle to particle attrition and compression which achieve size reduction.
Batching is the process of weighing the oxides according to recipes, and preparing them for mixing and drying.
Mixing occurs after batching and involve a variety of equipment such as dry mixing ribbon mixers (a type of cement mixer), Mueller mixers, and pug mills. Wet mixing generally involve the same equipment.
Forming is making the mixed material into shapes, ranging from toilet bowls to spark plug insulators. Forming can involve: 1) Extrusion, such as extruding "slugs" to make bricks 2) Pressing to make shaped parts. 3) Slip casting, as in making toilet bowls, wash basins and ornamentals like ceramic statues. Forming produces a "green" part, ready for drying. Green parts are soft, pliable, and over time will lose shape. Handling the green product will change its shape. For example, a green brick can be "squeezed", and after squeezing it will stay that way.
Drying is removing the water or binder from the formed material. Spray drying is widely used to prepare powder for pressing operations. Other dryers are tunnel dryers and periodic dryers. Controlled heat is applied in this two-stage process. First, heat removes water. This step needs careful control, as rapid heating causes cracks and surface defects. The dried part is smaller than the green part, and is brittle, necessitating careful handling, since a small impact will cause crumbling and breaking.
Firing is where the dried parts pass through a controlled heating process, and the oxides are chemically changed to cause sintering and bonding. The fired part will be smaller than the dried part.
Assembly This process is for parts that require additional subassembly parts. In the case of a spark plug, the electrode is put into the insulator. This step does not apply to all ceramic products.
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