Method of chemical strengthening - Coursework Example

 A glass has low tensile strength compared to other solids. Glass is considered to be a liquid solid, an amorphous solid. It lacks crystalline structure which other solid used to have. Lacking crystalline structure, a glass has a very slow moving set of molecules with no definite arrangement. There are several techniques to strengthen tensile strength of a glass material. One technique is strengthening by means of so much heat and cold. The glass material is first heated at an extremely high temperature and then suddenly cooled.

The effect of heating is by loosing more the molecules and the sudden cooling is to compress it thereafter. Another method of strengthening is called chemical strengthening. This is where the glass material is submerged into a potassium nitrate solution. The high-mass potassium molecule, which is bigger, then replaces the sodium molecule in the glass material. It compresses the surface of the glass material and thus, making it more tough. 3. Griffith is concerned not for the strength of a material but for more, the defects.

His equation is to know the ability of a material to resist a flaw and fractures. He used Young’s modulus or the stress over strain ratio to get how much stress energy is needed for a material to rupture from a certain length of fracture. Needless to say, the less stress over strain ratio a material has the little stress energy it will need to rupture and collapse. Now steel in general has 200 GPa and a glass only has 90 GPa.