Preparing method for high-strength and large-specific-surface-area titanium black coating

Abstract

The invention relates to a preparing method for a high-strength and large-specific-surface-area titanium black coating. The preparing method comprises the following steps that firstly, a titanium or titanium alloy base body is pretreated; secondly, a porous titanium dioxide coating is prepared; thirdly, sample plasma cleaning is conducted; fourthly, TiOx modification treatment is conducted; and fifthly, TiNxOy doping treatment is conducted. According to the preparing method, the large-specific-surface-area titanium black coating which is endowed with optical and electrical conduction functional characteristics and is capable of meeting the requirements for friction, strength and binding force can be obtained.

Description

technical field [0001] The invention relates to the field of surface technology, in particular to a method for preparing a titanium black coating with high strength and large specific surface area. Background technique [0002] Titanium black (TiO x , 0<x<2; or TiN x o y , 0<x<1, 0<y<2) is a material with very good blackness, not only has TiO 2 It has the characteristics of high temperature resistance, anti-oxidation, anti-electrochemical corrosion, and biological activity, and has functional properties such as non-magnetism, high electrical conductivity, and optics, and is non-toxic and edible, and it is more environmentally friendly and edible; therefore, titanium Black is widely used in food, cosmetics, fuel cells, photovoltaics, chemicals and other fields. [0003] At present, the research on the preparation of titanium black materials mainly focuses on two aspects of powder and thin film materials. The specific preparation methods are: (1) At 800 °...

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Problems solved by technology

[0004] There are obvious deficiencies in these methods: (1) a coating structure with a certain strength cannot be obtained; if the obtained titanium black powder is sprayed twice and sintered, some functional properties of titanium black will be destroyed; The film material has low mechanical strength, poor bonding with the substrate, and no anti-friction and anti-scratch capabilities; (2) High temperature processing is required, high equipment requirements, and there are deficiencies in high energy consumption and low efficiency; (3) Technical difficulty Large, temperature, atmosphere, mixing uniformity, a slight change in any of the three parameters can lead to changes in the composition of titanium black, and then affect the performance of the product

[0005] Chinese patent authorization announcement number CN103214032A discloses "a method for preparing black titanium dioxide by hydrogen plasma-assisted hydrogenation at low temperature, which is characterized in that the method includes: placing titanium dioxide in a closed system, and vacuuming the closed system so that the pressure is less than 30Pa ; Pass a mixed atmosphere of hydrogen and argon into the closed system, wherein the molar ratio of argon and hydrogen in the mixed atmosphere is (0~20): 1, and the content of argon cannot be 0; heating the Titanium dioxide to 100-600°C, adjust the flow rate of the mixed atmosphere so that the pressure in the closed system is 50-500pa; turn on the radio frequency power supply to generate active hydrogen plasma to treat the titanium dioxide for a specified time, wherein the radio frequency is used The power supply ionizes hydrogen molecules to generate active hydrogen plasma for reducing the titanium dioxide to obtain black titanium dioxide"; successfully reduces the preparation temperature of titanium black; but this method is also only suitable for the production of powder or thin film titanium black, and cannot be obtained with the matrix Coating structure with good bonding force and high mechanical strength; and this process requires special professional equipment to complete

[0006] China Patent Authorization Announcement No. CN101177773A "A preparation method of a black titanium oxide film on the surface of titanium, the titanium or titanium alloy sample with a clean surface is subjected to atmospheric oxidation, anodic oxidation or micro-arc oxidation to form a thick film on the surface of the titanium or titanium alloy sample. For a titanium oxide film larger than 0.01 μm, after washing and drying the sample with a titanium oxide film on its surface, it is placed in a vacuum environment or a non-oxidizing atmosphere for heat treatment, and a black titanium oxide film is formed on the titanium surface; The vacuum environment mentioned above refers to a vacuum environment with a vacuum degree higher than 5 Pa, and the non-oxidizing atmosphere refers to an inert atmosphere"; it is announced that TiO2 is prepared on the surface of titanium by atmospheric oxidation, anodic oxidation or micro-arc oxidation. 2 Oxide film, in vacuum or inert gas protection heat treatment, to obtain black oxide film; this method also has shortcomings: (1) when using atmospheric oxidation and anodic oxidation as the basic modification layer, the strength of the coating is limited (the resistance of the oxide layer rubbing and scratching are poor), and the coating is thin and the specific surface area is small; (2) but the essence of this method is through the element diffusion between the coating and the substrate, that is, Ti reduces TiO at high temperature 2 (such as the aforementioned preparation method 1 of titanium black); the reaction process is carried out from the substrate to the coating surface. In order to improve the blackness of the coating surface and obtain a high-performance coating, it is necessary to increase the heat treatment temperature (above 800°C) and prolong the heat treatment time. , resulting in low efficiency and high cost; on the other hand, in the TiO 2 In the process of converting into titanium black, the change of grain volume will inevitably occur, which will cause coating pulverization, coating adhesion and coating mechanical strength to be greatly reduced; therefore, this method cannot protect the high adhesion strength and mechanical properties. Coating materials; and this process is not suitable for processing thin-walled parts of composite materials such as titanium aluminum and titanium copper (it takes a long time and is prone to deformation); The element ratio cannot be effectively controlled; even if the titanium black layer with the ideal oxygen-titanium ratio is obtained, the effective layer is too thin, and the overall coating has almost no functional properties

[0007] US patent document US20006093259A "COLORDEVELOPMENTMETHODOFMETALLICTITANIUMANDBLACKANDCOLOREDTITANIUMMANUFACTUREDBYTHISMETHOD" announced the use of hot alkaline chemical solution oxidation combined with high temperature nitriding to obtain black TiN x o y The method of coating; compared with the above-mentioned patent, this process is simple and easy; however, this process also has obvious deficiencies: (1) the coating obtained is thinner and has poor mechanical properties; (2) a large amount of Sodium titanate, resulting in a large amount of sodium titanate in the coating, the coating hardly has the functional characteristics of titanium black materials; (3) and this process requires nitriding treatment above 900 ° C, and there are also the same problems as the above patents Insufficient, almost no functional properties; and the obtained coating has low mechanical strength; (4) The specific surface area of ​​the coating is small

[0011] Therefore, the main component of the coating prepared by this process is TiO 2 -TiN gradient coating, the black coating surface obtained at lower temperature is also a mixture of TiN and titanium dioxide, which has poor uniformity and does not have the functional characteristics of titanium black; on the other hand, the TiN produced by this process is mainly It is preferentially formed in the micropores on the surface, which closes the micropores on the surface and reduces the specific surface area of ​​the coating, which is not conducive to the function of the coating.

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