Preparation method of fuel cell metal pole plate ceramic phase low-temperature nucleation nano coating

Abstract

The invention relates to a preparation method of a fuel cell metal pole plate ceramic phase low-temperature nucleation nano coating, which comprises the following steps: sequentially depositing a metal transition layer and a ceramic phase nanocrystalline coating on the surface of a metal bipolar plate, and then carrying out chemical etching treatment or dry etching on the bipolar plate coated with the coating, and finally, cleaning and drying to obtain the high-crystallinity ceramic phase nanocrystalline coating. Compared with the prior art, the method has the advantages that nucleation and crystallization of the ceramic phase can be promoted, meanwhile, the influence of high deposition temperature on the metal pole plate base material is avoided, the performance stability of the ceramic phase coating in the proton exchange membrane fuel cell can be improved through surface metal phase etching removal, and the service life of the fuel cell metal pole plate is prolonged.

Description

technical field [0001] The invention belongs to the technical field of fuel cells, and relates to a low-temperature preparation method of a high-crystalline ceramic nanocrystalline coating of a metal electrode plate of a fuel cell. Background technique [0002] Proton Exchange Membrane Fuel Cell (PEMFC) has been widely used in transportation, national defense, electronic products and other fields due to its high conversion efficiency, no pollution to the environment, low working temperature, and long working life. In the structure of the proton exchange membrane fuel cell, the bipolar plate occupies most of the space and cost, and the service environment of the fuel cell is a kind of SO-containing 4 2- ,Cl - ,F - The high temperature (60~90℃) and strong acid (pH=1~3) environment of plasma, so higher requirements are put forward for the physical and chemical properties of the bipolar plate: the ideal bipolar plate material must be electrical and thermal It is a good condu...

AI Technical Summary

Problems solved by technology

Although graphite coating and noble metal coating have good chemical stability and electrical conductivity, the deposition rate of the former is too slow, resulting in high time cost, and the latter is not suitable for mass production due to its high material cost; conductive polymers The chemical properties of the coating are not very stable, and the degree of bonding with the substrate cannot meet the requirements

Metal-based ceramic coatings, especially metal carbide coatings, have been widely used in actual production due to their excellent corrosion resistance and electrical conductivity, fast deposition rate, and low preparation cost. Patent application CN201911269627.6 discloses A composite coating for fuel cell plates and its preparation method, the invention points out that the conductive corrosion-resistant coating is one or more composite layers of metals, metal carbides or carbon materials deposited on the surface of fuel cell plates The carbide coating is composed of carbides of chromium (Cr), carbides of nickel (Ni), carbides of titanium (Ti), carbides of niobium (Nb), and carbides of tantalum (Ta). One of carbides, carbides of tungsten (W) elements, or carbides of zirconium (Zr) elements, but there is no mention of how to control the crystallinity of the carbide coating and the control method of the elemental metal phase in the coating

Patent CN201810219089.9 proposes a method for improving the electrical conductivity and corrosion resistance of the carbide coating on the bipolar plate of the fuel cell, which includes depositing a metal transition layer and a metal carbide coating on the surface of the metal bipolar plate, and then The bipolar plate of the first layer is etched to change the surface structure and composition of the carbide coating. Finally, after cleaning and drying, a carbide coating with improved corrosion resistance and conductivity is obtained. The invention proposes to use an etching method to remove the carbide coating. However, there is no technical way to enhance the crystallization of metal carbide coatings, which leads to harsh requirements for etching process parameters.

[0004] At present, the main problems faced by ceramic coatings are: (1) The nucleation of ceramic nanocrystals is difficult, the size is small, the nucleation temperature is high, and the influence on the metal substrate is large; (2) The ceramic nanocrystal coatings using vapor deposition are difficult to avoid The existence of the phase has a significant impact on the stability of its service performance in fuel cells

However, the methods for improving the performance of metal carbide coatings in the above-mentioned published patents are relatively complicated, which increases the cost of coating preparation, and does not directly use the etching process to improve the corrosion resistance and conductivity of metal carbide coatings. to improve

Lewin E et al. Nanocomposite nc-TiC / a-C thin films for electrical contact applications published in "Journal of Applied Physics" (2006, Vol. 100, No. 5, pp. 85-88) TiC intercalation prepared by non-reactive magnetron sputtering The composite coating in the amorphous carbon network structure, in which the embedding of TiC can reduce the internal stress of the coating, and change the amorphous carbon structure to affect the wear resistance of the coating, but the coating is mainly used to improve the mechanical properties of the amorphous carbon film. Performance, does not have corrosion resistance under high potential in complex vehicle working conditions

Images