Hi Gaurav,
Check this link. It might be helpful to understand the basics.
SAP EAM - SAP Enterprise Asset Management, SAP Plant Maintenance: Maintenance Processing
Breakdown maintenance is an maintenance activities performed in order to make equipment UP & Running when it is under breakdown
E.g. Crane stopped working suddenly which is needs breakdown maintenance to make it up & running.
Corrective maintenance When you observe that breakdown was due to some specific issue e.g. Engine motor damage. And you observe that whole Equipment may stop again due to engine motor. So permanent fix is to replace engine motor. Hence you schedule a work order to replace this engine motor. Such kind of maintenance is termed as Corrective maintenance.( It starts with notification OR you can directly create an order)
Regards,
Amol