Study on Manufacture Process, Micro-Hardness and Hall-Petch Relation of Pure Rutile Phase TiO<sub>2</sub> MAO Coating

A pure rutile TiO 2 coating was produced on titanium substrate by MAO processing in Al (OH) 3 colloidal solution. It is proved that Al (OH) 3 in the solution blocks the produce of anatase phase TiO 2 . The rutile MAO coating has the advantage of high micro-hardness. Phase composition of the coating is analyzed by XRD in the study. Relation between rain size and micro-hardness of the coating is discussed and it is proved that the two parameters conform to the Hall-Petch relation.