Particle board is the lower end material for kitchen cabinets for your kitchen remodel.
The biggest advantage is they are less expensive.
The biggest disadvantage is they are the least durable.
It is wood particles (wood chips, sawmill shavings, saw dust) pressed together with a resin or other binder, which is pressed and extruded (which means it is squeezed out of a machine).
Please do not confused it with fiber board, which is different.
All particle board cabinets are covered in a veneer, which is a very thin layer of wood (almost a paper) that is carefully glued onto the wood, giving it the desired look and feel.
If cost is your greatest concern in the selection of your kitchen cabinets, particle board is the way to go.
I hope this information is useful to you. Other details about cabinet construction is available in other articles.