Topics in Basic TechnologyType of Lines in Technical Drawings Len Academy questions for Basic Technology, JSS2, 2nd Term Len Academy questions for Basic Technology JSS2, 2nd Term, Part 2 Maintenance, Types of Maintenance Wood, Characteristics of Hardwood and Softwood Ceramics, Types and Properties
Academic Questions in Basic Technology
Ceramics are not metals, neither are they plastics. They are all around us and include things like tile, bricks, spark plugs, diamond and glass. Ceramics as a topic and a product is indeed very broad and this had made it's defination somewhat complex. Infact, often times, It is defined as what it's not. Defining ceramics by it's characteristics can be a little complicated because not all of them share the same feature. For instance ceramics like glass and mugs tend to be hard and also are bad conductor of electricity. Graphite on the other hand is a ceramic (because it is inorganic and metallic), but it's brittle (soft) and also a good conductor of electricity. That's why you would see a lot of textbook define it as an inorganic and non-metallic material. They are also refractory by nature and require a very high amount of heat and subsquent cooling to be formed.
Note: inorganic imply that they they do not have their origin from any living organism while refratory means that they are capable of withstanding a variety of abuses like very high temperatures and chemical attacks.
Normally, ceramics are generally made by taking clay from the ground and mixing it with water. It is then shaped into any form and fired inside an oven (called kiln) at a very high temperature. They may then be decorated with a waterproof, paint-like substances called glazes.
Ceramics may be classified into two. These are:
They are made completely form clay. We can put them into:
They are based on metallic oxides or non-oxides (or combinations of both) and are not generally clay based. The main oxides used in advanced ceramics are aluminium oxide (Al2O3), Magnesium oxide (MgO) and zirconium oxide (ZrO2). The non-oxides are mainly carbides, borides and silicides, e.g, boron carbide (B4C) and silicon carbide (SiC). Regarding how they are produced, firstly, these oxides are thoroughly grounded into very fine powders and then shaped into a green body fired at a very high-temperature (1,600–1,800°C) in an oxygen-free atmosphere (and allowing the tiny grains of each ceramic components to join together, a process called sintering). The end result is a very hard, durable and corrosion-resistant product. Advanced ceramics are used in metal production and electronics.
Ceramics may have constrasting physical and chemical properties, but in general,
Amazing facts in Basic Technology
Volkswagen group of companies own some of the top cars of the world. These are Audi, Bentley, Bugatti, Ducati, Lamborghini and Porsche
NOTABLE POINTS IN Basic Technology