Hard particles cause abrasive wear. In everyday life, a well-known form of abrasive wear is sanding with sandpaper. Abrasive wear also occurs when a medium containing sand flows through a gutter or pipe. The grains of sand 'chip' the surface. Another example is contaminated lube oil. The hard parts in the contaminated oil cause a cutting movement between bearings or gears for example. Especially when the surfaces of these materials are insufficiently wear-resistant.