even lower level the material subjected to the surface treatment of the present invention is aluminum or an aluminum alloy specific examples thereof include pure aluminum flattened aluminum material cast aluminum and die cast aluminum material and the present invention may be applied to any type of material the surface treatment is effective in improving wear resistance corrosion resistance and like properties as a pretreatment for the material to be treated it is sufficient to remove contaminants e g oil adhering thereto however the surface treatment may be carried out after the material is subjected to an alkali etching with sodium hydroxide or the like or and to acid cleaning in order to carry out the surface treatment of the present invention the aluminum or aluminum alloy to be treated is soaked in the aforesaid treating fluid i e the heated aqueous solution the temperature of the treating fluid in which the aluminum or aluminum alloy is soaked is usually in the range of 70 to 100 u00b0 c preferably 75 to 99 u00b0 c and more preferably 80 to 98 u00b0 c if the temperature of the treating fluid is lower than 70 u00b0 c the reaction will undesirably be retarded to prolong the treating time on the other hand if the temperature of the treating fluid is higher than 100 u00b0 c the evaporation of the treating fluid will increase to an undesirable degree as to the treating time it is sufficient to soak the material for about 2 minutes because the film forming reaction is completed in about 1 minute or so however since the resulting film.