Name Two solid materials having very low linear expansivity ?
To find two solid materials with low linear expansivity, we can start by understanding the concept of linear expansivity. Linear expansion refers to the increase in length of a material when it is heated.
One method to determine the linear expansivity of a material is by referring to its coefficient of linear expansion (α). The coefficient of linear expansion is a proportionality constant that relates the change in length of a material to the change in temperature. It is expressed in units of temperature inverse (e.g., 1/°C or 1/°F).
Materials with low linear expansivity will have low coefficients of linear expansion.
Now, to find two solid materials with low linear expansivity, we can consider:
1. Invar (also known as Invar 36 or Ni-Fe 36) - This is an iron-nickel alloy known for its extremely low coefficient of linear expansion. Invar has a coefficient of linear expansion of around 1.3 × 10^-6/°C, making it highly resistant to dimensional changes with temperature variations.
2. Pyrex - Pyrex glass is a borosilicate glass that is known for its low coefficient of linear expansion. It has a coefficient of linear expansion of approximately 3.25 × 10^-6/°C. Compared to regular soda-lime glass, Pyrex glass exhibits less expansion when exposed to heat, making it suitable for applications that involve thermal changes.
These are just two examples of solid materials with low linear expansivity. There are other materials with similar characteristics, and their coefficients of linear expansion may vary slightly depending on the specific composition and manufacturing processes.