A titanium or titanium alloy material for a separator of a polymer electrolyte fuel cell having high contact conductivity with carbon and high durability, and including an oxide film formed on a titanium or titanium alloy substrate by a stabilization treatment performed after a passivation treatment, and one or more kinds of conductive materials selected from carbide, nitride, carbonitride, and boride of tantalum, titanium, vanadium, zirconium, and chromium, the conductive materials being dispersed in the oxide film and having a major axis diameter of from 1 nm to 100 nm. A contact resistance value with a carbon paper is 20 m.Math.cm.sup.2 or less at a surface pressure of 10 kgf/cm.sup.2 before and after an accelerated deterioration test in which the titanium or titanium alloy material is immersed in a sulfuric acid aqueous solution having an adjusted pH of 4 at 80 C. for four days.

The composition ratio of a titanium hydride [I.sub.TiH/(I.sub.Ti+I.sub.TiH)]100 found from the maximum intensity of metal titanium (I.sub.Ti) and the maximum intensity of the titanium hydride (I.sub.TiH) of the X-ray diffraction peaks measured at a surface of a titanium or a titanium alloy at an incident angle to the surface of 0.3 is 55% or more, a titanium oxide film is formed on an outermost surface of the titanium or the titanium alloy, and C is at 10 atomic % or less, N is at 1 atomic % or less, and B is at 1 atomic % or less in a position where the surface has been subjected to sputtering of 5 nm with argon. The titanium oxide film is formed by performing stabilization treatment after performing passivation treatment in prescribed aqueous solutions, and has a thickness of 3 to 10 nm.

The composition ratio of a titanium hydride [I.sub.TiH/(I.sub.Ti+I.sub.TiH)]100 found from the maximum intensity of metal titanium (I.sub.Ti) and the maximum intensity of the titanium hydride (I.sub.TiH) of the X-ray diffraction peaks measured at a surface of a titanium or a titanium alloy at an incident angle to the surface of 0.3 is 55% or more, a titanium oxide film is formed on an outermost surface of the titanium or the titanium alloy, and C is at 10 atomic % or less, N is at 1 atomic % or less, and B is at 1 atomic % or less in a position where the surface has been subjected to sputtering of 5 nm with argon. The titanium oxide film is formed by performing stabilization treatment after performing passivation treatment in prescribed aqueous solutions, and has a thickness of 3 to 10 nm.

A method of making a treated article having a metal surface. The method includes treating the metal surface with a primer composition comprising a secondary or tertiary amino-functional compound having at least two independently selected silane groups to provide a primed metal surface and subsequently treating the primed metal surface with a treatment composition comprising a fluorinated compound represented by formula Rf{X[Si(Y).sub.3-x(R).sub.x].sub.y}.sub.z. An article treated by such a method is also disclosed. The use of a secondary or tertiary amino-functional compound having at least two independently selected silane groups as a primer for a metal surface before treatment with the fluorinated silane and a method of treating a metal surface with a treatment composition including the secondary or tertiary amino-functional compound having at least two independently selected silane groups and certain fluorinated silanes are also disclosed

A method of making a treated article having a metal surface. The method includes treating the metal surface with a primer composition comprising a secondary or tertiary amino-functional compound having at least two independently selected silane groups to provide a primed metal surface and subsequently treating the primed metal surface with a treatment composition comprising a fluorinated compound represented by formula Rf{X[Si(Y).sub.3-x(R).sub.x].sub.y}.sub.z. An article treated by such a method is also disclosed. The use of a secondary or tertiary amino-functional compound having at least two independently selected silane groups as a primer for a metal surface before treatment with the fluorinated silane and a method of treating a metal surface with a treatment composition including the secondary or tertiary amino-functional compound having at least two independently selected silane groups and certain fluorinated silanes are also disclosed

An object of the present invention is to provide a method for treating an object to be treated, which has an excellent etching amount with respect to a metal layer containing at least one selected from the group consisting of molybdenum and tungsten and has excellent flatness of a surface of the metal layer after the treatment. The method for treating an object to be treated according to an embodiment of the present invention includes a step 1 of bringing the object to be treated, which has a metal layer containing at least one selected from the group consisting of molybdenum and tungsten, into contact with a first treatment liquid to form a metal oxide layer, and a step 2 of bringing the object to be treated, which has the metal oxide layer, into contact with a second treatment liquid to remove the metal oxide layer, in which the first treatment liquid contains an organic solvent and an oxidizing agent, and the second treatment liquid contains water.

An object of the present invention is to provide a method for treating an object to be treated, which has an excellent etching amount with respect to a metal layer containing at least one selected from the group consisting of molybdenum and tungsten and has excellent flatness of a surface of the metal layer after the treatment. The method for treating an object to be treated according to an embodiment of the present invention includes a step 1 of bringing the object to be treated, which has a metal layer containing at least one selected from the group consisting of molybdenum and tungsten, into contact with a first treatment liquid to form a metal oxide layer, and a step 2 of bringing the object to be treated, which has the metal oxide layer, into contact with a second treatment liquid to remove the metal oxide layer, in which the first treatment liquid contains an organic solvent and an oxidizing agent, and the second treatment liquid contains water.