Abrasives - What Are They and How Do They Work

In the aerospace and aviation industries, every rough surface, sharp edge, or imperfection has the potential to lead to disastrous consequences. Or, at the very least, cost a lot of money as a result of decreased efficiency caused by higher friction and wear-and-tear. As a result, abrasives are an important part of the manufacturing process.

Abrasives are the hard crystals either manufactured or found in nature are materials used to clean, grind, or polish hard surfaces like metals and alloys. They’re also commonly used to work with other materials such as stone, glass, plastic, wood, and rubber. Abrasives work by scratching. The particles will first penetrate the surface and then cause a tearing off of particles. However, it only works if the abrasive is has a higher hardness rating than the abraded material. As a result, the most common abrasives are made of materials like aluminum oxide, silicon carbide, cubic boron nitride, and even diamond, which have Mohs hardness ratings of 9+.

However, for the last 100 years or so, manufactured abrasives have largely begun to replace natural abrasives. Synthetic diamonds and lab-made silicon carbide and aluminum oxides have replaced their natural counterparts. And that’s mostly because manufactured materials are more superior in their uniformity and controllable properties.

In most industries, what kind of abrasive being used will depend on what the application is. Hard and brittle abrasives like silicon carbide and aluminum oxide tend to form sharp edges so they’re best for precision and finish grinding. On the other hand, tougher abrasives that resist fracture and last longer are used for rough grinding. The application also dictates which of the 3 types of abrasives are used,

1) bonded to form solid tools such as a grinding wheel;

2) coated on backings made of paper or cloth like sandpaper;

3) loose and held in some liquid or solid carrier such as sandblasting.