Composite ceramic coating containing precious metal intermediate layer and preparation process thereof

Abstract

The invention provides a preparation process of a composite ceramic coating containing a precious metal intermediate layer. The preparation process comprises the following steps that (1) surface oxides of a titanium-based alloy substrate are removed, and washing and drying are carried out; (2) a precursor solution A is prepared by sulfuric acid and a platinum compound; (3) the titanium-based alloyis used as a working electrode, metal platinum or graphite is used as a counter electrode, the titanium-based alloy and the metal platinum or graphite are placed in the precursor solution A for electro deposition, washing and drying are carried out, and a platinum-plated titanium-based alloy is obtained; (4) anhydrous ethanol, a sodium nitrate solution and precursor alkyl silicate are prepared into a mixed solution, the pH value of the mixed solution is adjusted with acid, stirring is carried out, and a precursor solution B is obtained; (5) the platinum-plated titanium-based alloy is used asa working electrode, and metal platinum or graphite is used as a counter electrode, the platinum-plated titanium-based alloy and the metal platinum or graphite are placed in the precursor solution B for secondary electro deposition, washing and drying are carried out, and a micro-nano-oxide coating on the surface of the substrate is obtained; and (6) the platinum-plated titanium-based alloy with the micro-nano-oxide coating on the surface is subjected to heat treatment, and the composite ceramic coating containing the precious metal intermediate layer is obtained on the surface of the substrate after the heat treatment.

Description

technical field [0001] The invention relates to the field of metal-ceramic composite materials, in particular to a composite ceramic coating with a noble metal intermediate layer, which uses a titanium-based alloy as a matrix, has excellent high temperature resistance and good oxidation resistance, and a preparation method thereof. Background technique [0002] Titanium-aluminum alloy has the advantages of low density, high specific strength, high elastic modulus, and good high-temperature creep resistance. It is a high-temperature material with great application prospects. part. However, the actual use temperature of titanium-aluminum alloy is limited to below 750°C, because at higher temperatures, titanium and aluminum have similar affinity with oxygen, and TiO is formed on the surface of the alloy. 2 and Al 2 o 3 In the mixed layer, the growth rate of the oxide film is very fast, and it is easy to peel off. [0003] In order to overcome the above shortcomings, scholar...

AI Technical Summary

Problems solved by technology

[0004] On January 19, 2018, the Chinese Patent Office disclosed a patent application for a high-temperature-resistant titanium alloy plate. The application publication number is CN107604210A. It is also actively doped with elements such as Si, V, C, Mn, Mo and Co, and introduces elements such as Nb, Re, Y and Ce among the inevitable elements, that is, in essence, adding alloy elements to improve its high temperature resistance. Oxidation performance, but it also leads to a decrease in the mechanical properties of alloys with titanium and aluminum as the main component, which brings adverse effects

[0005] On February 2, 2018, the Chinese Patent Office disclosed the authorization of an invention patent for a preparation method of a titanium-based alloy anti-high temperature oxidation composite coating. The authorized announcement number is CN105714294B. A micro-nano oxide coating is prepared on the surface of the substrate, and the coating is coated with a metal aluminum coating with a thickness of 1-30 μm to form a double-coating structure, which greatly improves its high-temperature oxidation resistance and avoids the metal coating. The interdiffusion between the substrate and the substrate leads to the problem of easy precipitation of hard and brittle phases. However, because the intermediate layer is a micro-nano silica coating, it is also a ceramic coating. Although micro-nano silica and titanium-aluminum alloy There is chemical bonding between the substrates, which can greatly reduce the influence of the low bonding strength between the ceramic coating and the substrate, but this is still an unavoidable problem. layer, and its bonding strength with the middle layer is also low, so although its high temperature oxidation resistance has been significantly improved, the bonding strength between the coating and the substrate and between the coating and the coating is still unsatisfactory.

[0006] In addition, the article "Effect of a magnetron sputtered (Al 2 o 3 -Y 2 o 3 ) / (Pt-Au)laminated coating on hot corrosion resistance of 8Nb-TiAl alloy"records the tests and results of improving the hot corrosion resistance of high-niobium titanium aluminum alloys with aluminum yttrium oxide and platinum composite coatings. Platinum coating on the surface has a significant effect on improving the thermal corrosion resistance of high-niobium titanium-aluminum alloys. However, platinum is easily corroded by many substances such as various oxidants, strong alkalis, easily reduced heavy metal elements and sulfur under high temperature conditions, while aluminum yttrium The oxide itself is difficult to produce a good protective effect on platinum, resulting in extremely limited applicability, and it is prone to early corrosion damage in many use environments, which leads to a rapid decline in performance

Images