Downhole motors include a stator, which may be formed from a steel material and comprise a bore. At least one surface of the stator may be treated with a surface treatment. The surface treatment includes a nitrided region comprising nitrogen diffused into the steel material and a ceramic material adjacent to the nitrided region; the ceramic material defining an interior surface of the stator defining the bore. Methods of making downhole motors may include exposing a stator to an elevated temperature to heat the stator in a nitrogen-rich environment. Nitrogen may be diffused into a steel material of the stator and a nitrided region may be formed at one or more surfaces of the stator. The stator may be cooled. The stator may be removed from the nitrogen-rich environment. A ceramic material may be coated on the nitrided region of the stator.