For some years I have used Ceramica muffin fans for low noise and long life. They use a ceramic bearing which is quieter than ball bearings, but longer life than sintered bronze bearings which dry out.
In the last month, I have replaced three Ceramica fans that have failed, one with less than a year’s service and two with less than one month’s service.
Above, a pic of the 125mm impeller which has cracked radially from the centre. This fan had been in service in a computer power supply for less than one year.
The fan above is the one that was used to replace the one in the first pic, failed after less than one week.
The fan above was installed in another computer just three weeks ago and was removed as a matter of course due to the reliability issues with the two fans pictured earlier. This one has developed a cracked frame (upper right spar).
Though I have had better success with Ceramica fans in the past, this recent experience has convinced me to not only not use them again, but to replace them in the various power supplies where they have been installed.
I wrote to Ceramica informing them of the problem, my email was ignored.
Update 26/05/2016: The distributor has recently supplied three replacement fans, and I have installed one for trial… more if it fails.