Electroless plating Co–P films for high performance magnetic rotary encoders

The recording media is of crucial importance for magnetic rotary encoders of high resolution and accuracy. In the present study, the potential use of electroless plating Co–P films as the recording media for magnetic encoders was investigated. The microstructure and chemical states were analyzed by field emission scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The results indicated that Co and P co-existed as elementary substances in the as-deposited Co–P films, where Co grains had an hexagonal closed-packed structure with c-axis in the plane. The read and write characteristics revealed that the Co–P films could be recorded 2048 original magnetic poles while the amplitudes of the output square and sinusoidal waves were uniform. It is suggested that the Co–P films can be a promising candidate as recording media for high performance magnetic rotary encoders, which may greatly improve the resolution and accuracy of rotational speed or displacement measurements in industrial and automotive applications.