Toughened glass is used over certain styles of glass when the main properties need to be strength, thermal resistance and safety as the main important considerations. Tempered glass is mostly seen in the side and rear windows in automobiles this is because its able to shatter into small cubes rather than sharp-edged shards. Tempered glass is also used in buildings for unframed structures like frameless doors, structurally-loaded applications, and any other application that would become dangerous if impact was made.
Toughened glass is made from via a thermal tempering process. The glass is placed onto a roller table, taking it through a furnace that heats it to above its annealing point of about 600 °C. The glass is then rapidly cooled with forced draughts of air while the inner portion of the glass remains free to flow for a short time.
Another way to produce toughened glass is a chemical process. This involves forcing a surface layer of glass at least 0.1mm thick into compression. The of the sodium ions in the glass surface with the 30% larger potassium ions, by immersion of the glass into a bath of molten potassium nitrate. Using the meathod of chemical toughening makes it have anincreased toughness compared with thermal toughening, and can be used for glass objects that have complex shapes.
The term toughened glass is generally used to describe fully tempered glass but is sometimes used to describe heat strengthened glass as both types undergo a thermal 'toughening' process. The strength of the glass does not change the deflection it just means that it can deflect more before breaking. Annealed glass deflects less than tempered glass under the same load.
Toughened glass must be cut to size or pressed to shape before toughening and cannot be re-worked once toughened. So if any mistakes are made there is no erasing them. Also all Polishing the edges or drilling holes in the glass is carried out before the toughening process starts so no changes can be made after. Also as the glass has balanced stresses inside, damage to the glass will eventually result in the glass shattering into thumbnail sized pieces. The glass is most susceptible to breakage due to damage to the edge of the glass where the tensile stress is the greatest, but shattering can also occur in the event of a hard impact in the middle of the glass pane or if the impact is concentrated. This means it would need to be striked with something with a point. Another disadvantage is that can be unsecure as it has Using toughened glass can pose a security risk in some situations due to the tendency of the glass to shatter completely upon hard impact rather than leaving shards in the windowsill.
Ceramics
Ceramics are non toxic ceramics, inorganic ceramic that is made up of porous clay which contains a mixture of kaolin, clay, quart (quartz is a crystalline form of silica) and feldspar. Feldspar is the name of a group of rock-forming which make up as much as 60% of the 's . Earthenware is a common material, which is used mainly for tableware and decorative objects.
The term ceramics concerns non materials which are formed by the action of heat. Most ceramic materials are hard, porous, and brittle.
Earthenware is one of the oldest materials used in . Another variation is red earthenware made from red clays this is very familiar and recognizable. Also white and buff colored earthenware clays are also commonly used.
For it to be used successfully earthenware needs to be fired to temperatures in the range of 1000 and 1150 degrees . The exact temperature will be influenced by the raw materials used and how the manufacturer wants the characteristics of the finished ware. The higher firing temperatures are likely to cause earthenware to bloat. After the firing has occurred the body of the ceramic is porous and opaque with colours ranging from white to red depending on the raw materials used.
Earthenware may sometimes be as thin as and other , though it is not translucent and is more easily chipped. Disadvantage of Earthenware is it is also less strong, less tough, and more than . But advantages are that its low cost and easier working making up for its disadvantages. Due to its higher , earthenware must usually be in order to be watertight.
Types of earthenware
Conclusion
Having looked at all the physical properties for the two examples I was given I feel that overall tempered glass are the more likely to be more successful as a mug.
Mugs made of earthenware have been proved to be most popular as they are cheap, easy to produce and can provide all different variation to please all sorts of consumers.
However I feel tempered glass are more aesthetically pleasing and stylish. They also were chosen as their compressive strength and malleability is far greater then that of ceramics.
This means even though they will be slightly more expensive then ceramics they will last longer. As they are less likely to break during manufacture and use. This is because they are not porous and more malleable.
