Understanding Nanoscience & Our Process
In order to understand how hypersonic plasma particle deposition (HPPD) enhances coating performance, it can be helpful to understand the fundamentals of material properties and nanoscience. All materials interact with the world around us in different ways. We are familiar with properties such as color, texture and volume, however, at the nanoscale there are three important properties help us determine the performance characteristic and quality of our coatings.
Hardness determines the materials resistance to deformation under pressure and is measured by indentation – the smaller the indentation the harder the material. Tests for hardness are commonly performed and are non-destructive. Pictured left is a chart of 5 common materials and their degree of hardness. As you can see, a diamond is a very hard material.
However, high hardness does not equal high toughness.
While hard, a diamond will crack or fracture easily. Window glass also cracks very easily, but most steel and metals do not. A fracture is the separation of materiel into two or more pieces in response to stress or temperature. Fracture toughness is a measure of a material’s resistance to fracture when a crack is present. Fracture toughness is measured using indentation and scanning electron microscopes (SEM). A shorter crack is equivalent to higher fracture toughness.
How much stress can a material take without breaking? This is elasticity. A material can stretch like a spring absorbing energy when a force is applied. A high elasticity means a large force can be applied then removed, and the material will return to its original shape.
The hardness, fracture toughness and elasticity all combine to dictate a material property called Wear Resistance . You can think about how all of the above three properties come together to create an overall material behavior. A diamond is hard but also fractures easily. Steel is resistant to cracking and has high elasticity making it an ideal structural material.
Smaller is Stronger.
Materials at the nanoscale will behave much differently than their larger “bulk” counterparts. The same materials will behave differently just because of their size. For example, a sugar cube will dissolve more slowly in water than fine grained sugar. A large block of ice melts more slowly than crushed ice.
Old fashioned windows were made of many smaller panes, stronger panes, and this reduced the chances of cracking ( fracture ). Glass makers soon began incorporating wire mesh into glass creating many tiny panes. When a crack forms, it is quickly stopped by the wire mesh.
Safety glass and engineered glass of today takes a different approach to preventing breakage. With a better understanding of how cracks form and grow, safety glass has been designed internally to control how the cracks grow, and this type of glass will fracture into many smaller pieces.
In essence, if you want to make something stronger, make it smaller. This idea is the cornerstone of understanding nanostructured films and the foundation of our coatings at Hypersonix.