Tempered Glass
Structure of Typical Glass
-
Made of: Silica (sand), silicon dioxide, sodium carbonate and other compounds.
-
Atoms and molecules are not arranged in orderly planes, have low mobility, cannot rearrange themselves.
Impact on Properties
Red Line: Movement of particle
Hard but breaks easily without high stress
-
Very Brittle: Lacks high mobility to shift in response to stress, external stress can't be redistributed.
-
Cracks To Shattering
-
At the tip of the cracks, stress can only be redistributed to a few number of atoms/molecules.
-
Stress will be concentrated → Shatter easily.
-
Brittle: Hard but breaks easily.
Tempered Glass: The Ultimate Solution
How Each Type of Glass Shatters
How The Tensile Strength of Tempered Glass Is Improved
In the manufacturing process...
-
Outer surface: Hardens faster than inner core, leading to compressive stress.
-
Inner core: Contracts slower than outer surface, tendency but inability to contract leads to tensile stress.
​​To deform the glass, external tensile stress exerted will have to overcome the already present compressive stress first.
Tensile Stress ("Pulling force")
Compressive Stress ("Pushing force")
Fun Fact: The colour of glass can be changed by adding specific minerals. For example, adding nickel oxide turns glass violet.