Permanent magnets are generally characterized by a "maximum operating temperature", above which point there is a loss of magnetization. This maximum temperature is significantly less than the Curie temperature, at which point all magnetization is lost. Maximum operating temperatures are dependent on the specific magnet, but the temperature range of concern is 80 C to 200 C.
Mechanical properties of the PCB suffer at around 120 C, however, high temperature withstanding and high glass-transition temperature circuit board materials are available, and can be incorporated into an E-circuit motor, increasing temperature withstanding to 180 C, which is comparable to "H" rated induction machines.