Question

How does the processing and structure of glasses affect fracture toughness for

1. annealed glass

2. silica glass

3. pyroceram

Answer 1

ANSWER

1.

Annealed glass

In this type of glass manufacturing, the glass is slowly cooled after it has been formed. To do proper annealing operation it is a must to heat the glass to its annealing temperature, for most of the glass the annealing temperature varies from 454 ⁰C - 480 ⁰C.

Annealing helps the glass to relieve the residual thermal stresses which were induced during the manufacturing process and quenching, and thus have high strength and durability

Applications-

• Window glass
• utensils

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2.

Silica Glass

Silica glass is a type of glass containing amorphous silica, and silica is the majority constituent of this glass, it is manufactured by fusing high purity silica sand which also consist of quartz crystals and the fusion temperature is about 1650 ⁰C. Fused silica glass has very low metallic impurities close to 10ppm. Silica glass has superior thermal and optical properties due to its high purity, it also has high melting and working temperature. Also, its low coefficient of thermal expansion makes it ideal for the manufacturing of precision mirrors.

Applications -

• Semiconductor devices
• Optical mirrors and lenses
• halogen lamps

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3.

Pyroceram

It is a ceramic glass material discovered by company Corning Glass, It is consist of magnesium aluminosilicate with titania nucleating agent. Pyroceram is extremely transparent thus used widely in optical applications, it's harder and stronger compared to normal soda-lime glass.

Applications -

• Microwave ovens
• Aerospace components
• High-temperature experiment equipments