metalling

Metalling refers to the process of laying down a surface of crushed stone or gravel, typically on roads or pathways. This material is often referred to as "metalling" itself. The process involves excavating the existing surface, laying down a sub-base layer, and then compacting several layers of increasingly fine aggregate on top. This creates a durable and permeable surface that can withstand traffic. Historically, metalling was a common method for road construction before the widespread adoption of asphalt and concrete.

The term "metalling" can also refer to the application of metal coatings to other materials, such as metal plating on plastic or other metals. This is often done for decorative purposes, to enhance corrosion resistance, or to improve electrical conductivity. Common metalling processes include electroplating, hot-dip galvanizing, and sputtering. The specific method and type of metal used depend on the substrate and the desired properties of the final product.

In some contexts, metalling might also describe the process of mixing metal powders with a binder to create a composite material. These metal-based composites can offer a unique combination of properties, such as high strength, wear resistance, and thermal conductivity. Applications range from aerospace components to specialized industrial parts. The exact definition can vary depending on the industry or specific field of application.