Composite coating for titanium alloy investment casting, surface coating and preparation method and application thereof

Abstract

The invention discloses a composite coating used for the titanium alloy investment precision casting, a surface coating and a preparation method and application thereof. Preparation materials of the composite coating used for titanium alloy investment precision casting comprise a refractory material, an adhesive, an anti-hydration agent and a regulator, wherein the refractory material comprises yttrium oxide, and the anti-hydration agent is a derivative of a saturated fatty acid. The structural formula of the derivative of the saturated fatty acid is shown in the following formula (1) that R represents an alkyl group, X and Y independently represent a substituent group, wherein the substituent group contains one or more of an alkyl group, a hydroxyl group, a phenyl group or a carboxyl group. The surface coating comprises the composite coating, and further comprises a wetting agent and a defoaming agent. The composite coating used for the titanium alloy investment precision casting andthe surface coating have the advantages of being simple in component, stable in performance, not easy to gel, not easy to dissolve in water, long in service life and low in production cost, and the reaction degree of yttrium oxide ceramic type shell and the titanium alloy prepared by using the coating is small, and the formed alpha adhesion layer is small in thickness.

Description

technical field [0001] The invention relates to the technical field of alloy investment precision casting, in particular to a composite coating for titanium alloy investment precision casting, a surface coating, a preparation method and application thereof. Background technique [0002] Titanium and titanium alloys are widely used in the aerospace industry, energy industry, marine transportation, and chemical industry due to their excellent properties such as low density, high specific strength, corrosion resistance, and good biocompatibility. However, titanium and titanium alloys have high chemical activity at high temperatures. At high temperatures, titanium will undergo chemical reactions to various degrees with various gases and commonly used refractory materials. The chemical reaction between the liquid titanium and the mold will not only cause a contamination layer on the surface of the titanium alloy casting, affecting its performance, but also deteriorate the surface...

AI Technical Summary

Problems solved by technology

The surface layer and adjacent layer coatings of oxide ceramic shells mainly use oxides such as yttrium oxide, zirconium acetate, zirconia, and calcium oxide that are less reactive with titanium liquid. Among them, the surface layer coating with yttrium oxide as filler The casting performance is good, but yttrium oxide is prone to hydration, and its slurry is very sensitive to pH changes and is easy to gel; zirconium acetate is usually used together with yttrium oxide or zirconia powder to make slurry, but due to the It does not have water resistance, so that the stability and reliability of the slurry coating prepared with yttrium oxide or zirconia powder are not as good as the coating of ethyl silicate and silica sol, and it will return to water after drying. Melting, causing the coating to peel off and bulge

In addition, the coating stability time in the prior art is usually only 1 to 2 days, and the temperature of the coating must be kept below 10°C, which increases the complexity of process control, and these defects seriously affect the coating process and mold shell. the quality of

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