The term fading denotes a reduction in brake effect.
Fading occurs at high load, for example when driving on steep roads or during hard braking after prolonged driving at high speed. The resulting high temperatures of up to about 700 °C cause the binding agent to be released from the brake pad. This forms a lubricating film between brake pad and brake disc, with a resulting loss of friction coefficient and therefore braking power.
To counteract this effect, the brake pads can be heat-treated by scorching, which eliminates any binding agent that has not cured.
When you change the pads, check that the contact areas of the caliper are free from dirt and grease.