What's the cavitation? And what's the difference between cavitation and abrasion?

1. Cavitation is defined as the process of formation of bubbles inside a liquid as a result of being subjected to low pressures at constant ambient temperature rather than addition of heat. It is said to occur in a liquid when bubbles of vapour form and grow inside a liquid as a consequence of reduced pressure. 

2.In two-phase liquids (containing suspended solid particles or gas bubbles), the impact of the particles can damage or even eliminate the protective layers or passive films that are normally stable in the absence of particles, and the local corrosion rate is then markedly accelerated. This phenomenon is called abrasion-corrosion.

Cavitation is decrease pressure inside the pipeline or valves leading to the water turned on or liquid inside the tube of liquid case of the situation and soft spoken this case at the entrance to the pump speed excess and difference pressure and thank you