If you own a good quality watch, chances are you are holding in your hands one of the toughest substances in the world. Sapphire is commonly used in many Apple watches. Also, almost all mobile phone cameras use sapphire for their lenses.
So, what is sapphire? Sapphire is found naturally as a precious stone, blue in color, and is used in jewelry. However, sapphire can be synthetically produced as well. It is this synthetically prepared sapphire that holds value in several industries due to its incredible mechanical and chemical properties.
Synthetic sapphire can be cut into different shapes and forms including sapphire windows, sapphire rods, etc. So, if you are interested in learning more about sapphire, please read on.
What Makes Sapphire Special?
So, why is sapphire so special and what makes it one of the most sought-after materials across industries? We will go into the details of the properties of sapphire later on in this blog, but here are a few reasons regarding what makes sapphire valuable.
- Sapphire is extremely hard and is resistant to any type of scratches. So, it’s an ideal material for camera lenses and watches.
- It allows a range of wavelengths to pass and is completely transparent to a wide range of wavelengths from infrared to ultraviolet.
- Sapphire can withstand a large range of temperature and pressure without deforming.
- Sapphire is incredibly resistant to chemicals including acids.
- It can be manufactured synthetically.
Having said that, why don’t we see wider use of sapphire? Why do we see Gorilla glass and not sapphire in most mobile phones? The reason is, sapphire is extremely hard so it gets difficult to work with it. Also, it’s much expensive, so if gadgets use sapphire, the prices automatically rise.
Optical and Mechanical Properties of Sapphire
One property that sapphire is most well-known for is its hardness. There are different ways to measure the hardness of a material. One such way is the Mohs scale that determines how difficult it is to scratch a material. Diamond comes first in the Mohs scale, so it makes diamond the hardest substance to scratch. Next on the scale comes silicon carbide, and sapphire holds third place in the Mohs scale.
The compressive strength of sapphire is also excellent. The compressive strength of a material determines the pressure it can support before breaking.
Sapphire has a compressive strength of around 2GPa which is equivalent to 40 elephants stacked on top of each other. In comparison, steel has a compressive strength of 250MPa which is almost 8 times less than sapphire. And Gorilla glass has a compressive strength of 900 MPa which is less than half of sapphire.
Another important property of Sapphire is that it is extremely resistant to chemicals. Sapphire Rod is almost inert to all chemicals, and thus, it is suitable for use where corrosive materials are used.
It has a very low thermal conductivity and also a very low thermal expansion coefficient. Meaning, it doesn’t deform or expand under high pressure or high heat.
Due to this excellent strength and scratch-resistant properties, sapphire is widely used in medical lasers, marine spectrometers, and underwater cameras.
Coming to the optical properties, sapphire has an excellent transmission window in the region of 300nm to 5500 nm thus covering the ultraviolet, visible, and infrared regions.
Because of this transmission property across a wide range of wavelengths, sapphire is often used in the infrared lens where normal glass won’t be suitable.
It is due to these excellent properties that sapphire is widely used across many different industries. The most excellent property of sapphire is that it can be manufactured synthetically and can be shaped into different forms including sapphire windows, sapphire rods, etc.