CN117550809A - Enamel coating highly thermally matched with metal matrix and preparation method thereof - Google Patents

Abstract

The invention provides an enamel coating that is highly thermally matched with a metal substrate and a preparation method thereof, and belongs to the technical field of surface protective coatings. The enamel coating is characterized by core-shell structure complex quartz particles dispersedly distributed in the enamel parent phase. By crushing the original single-phase quartz particles by ball milling, fine quartz particles with fresh cleavage surfaces are obtained. After high-temperature activation, core-shell structure multi-phase quartz particles are obtained, which are added to the mother phase of the enamel glaze to obtain a high degree of thermal contact with the metal matrix. Matching enamel coating. It can effectively solve the problem that the enamel coating is prone to cracking and peeling due to insufficient thermal matching with the metal substrate. The technical solution provided by the invention is energy-saving, environmentally friendly, low-cost, and has better process stability and controllability than the existing technology.

Description

An enamel coating highly thermally matched to a metal substrate and its preparation method

Technical field

The invention belongs to the technical fields of surface engineering and protective coatings, and specifically relates to an enamel coating that is highly thermally matched to a metal substrate and a preparation method thereof.

Background technique

As a technology with a long history, enamel coating still plays a unique and irreplaceable role in modern industry. For example, the hot-end components of aerospace engines serving in the marine environment are faced with severe high-temperature thermal corrosion problems. In this field of protection technology, Russian and Chinese researchers have shown that enamel coatings have significantly better high-temperature corrosion resistance than traditional alloy coatings. . According to reports, due to the high density brought by the glassy state of the enamel coating, some hot-end components of the Russian PД120 liquid oxygen/kerosene high-pressure afterburning rocket engine also use enamel coating to protect metal parts from combustion. In addition, Russia also uses enamel coatings to achieve good results in terms of hydrogen penetration resistance of nuclear reactor components. Storage water heaters require enamel coating to improve their corrosion resistance. Thermal power plants use the acid-resistant characteristics of enamel coatings to improve the corrosion resistance of air preheaters. It can be seen that the ancient enamel technology still plays an important role in modern industry. As we all know, the thermal expansion coefficient of enamel coatings is usually much lower than that of common metal materials, which leads to frequent chipping of enamel coatings due to excessive thermal stress. Therefore, improving the thermal matching between the enamel coating and the metal substrate is crucial to improving the service life and safety of the enamel coating.

There are current reports on improving the anti-flaking performance of enamel coatings. One solution is to redesign and optimize the enamel glaze formula [see literature: Chen Tao, a high-performance enamel glaze, Chinese patent, CN201210548990.3], so as to obtain the same effect as the metal matrix. The overall performance of the adaptation, however, the effectiveness of this method is limited by the type of metal substrate. Another solution is to increase its strength by adding refractory ceramic oxide particles or metal particles such as alumina [see literature: Du Zhuan, Chen Lin, Meng Guohui, Zhu Changfa, Zhao Ding, Wang Guoqiang, Enamel coating modification technology and application research progress, Material Protection, 2023(56)158-168+182], thereby improving its ability to resist thermal stress damage. This method worked to a certain extent, but it failed to solve the problem of thermal matching from the source.

The present invention adopts a brand-new solution, that is, the phase change of active multi-phase particles is used to coordinate the deformation of uranium enamel to form a high thermal expansion effect to achieve a high degree of thermal matching with the metal matrix. This solution can be based on existing enamel glazes, without the need to redesign the formula for high-temperature melting, regulate its thermal expansion coefficient, and can be applied to a variety of metal substrates. At the same time, the process cost is low, energy saving and environmental protection. Adopting this solution will more effectively improve the service life and safety of the enamel coating.

Contents of the invention

The invention provides an enamel coating that is highly thermally matched with a metal substrate and a preparation method thereof, which effectively solves the problem that the enamel coating is prone to cracking and peeling due to insufficient thermal expansion coefficient and the metal substrate.

The technical solution of the present invention is:

An enamel coating that is highly thermally matched to a metal substrate and a preparation method thereof. The enamel coating contains a core-shell structure complex quartz particle phase and a silicate enamel glaze parent phase. The preparation method is as follows: first, coarse-sized original single-phase quartz particles are ball-milled to obtain fine quartz particles with fresh cleavage surfaces, and then the above-mentioned newly prepared fine quartz particles are put into a high-temperature furnace for activation to obtain core-shell. Structural multiphase quartz particles, and then mix the above activated multiphase quartz particles into the enamel glaze and spray or brush on the substrate, and then control the dissolution and phase transformation process of the multiphase quartz particles by adjusting the firing temperature and time to obtain Highly thermally matched enamel coating to the metal substrate.

The core-shell structure of the multi-phase quartz particle phase is a particle structure composed of cristobalite or phosphoquartz phase as the shell quartz phase as the core.

The particle size of the core-shell structure composite quartz particle phase is 2-6 microns, and the initial core/shell size ratio of the particles is 100-1000.

The core-shell structure composite quartz particle phase particle content is 35%-65% by volume.

The mother phase of the enamel is a silicate glass phase. In addition, it may contain ceramic phase particles such as alumina, zirconium oxide, and chromium oxide with a total volume fraction of no more than 25%.

The size of the original single-phase quartz particles is 10-50 microns, and the size of the quartz particles with fresh cleavage surfaces obtained by ball milling is controlled at 2-6 microns.

The temperature of the high-temperature activation furnace is 1000℃-1400℃, and the activation time is 2-10 minutes.

The complex quartz particles are mixed into the enamel glaze using a slow stirring method, with a rotation speed of 20-200 rpm and a stirring time of 2-5 minutes.

The enamel firing temperature is 800℃-1000℃ and the time is 10-1200min.

Advantages of the invention:

The enamel coating prepared by the present invention can achieve the effect of regulating the thermal expansion coefficient of the enamel coating without changing the glass phase composition of the enamel glaze. Therefore, for the existing enamel glaze system, there is no need to redesign the formula for a high-energy-consuming high-temperature smelting process, which can significantly improve Its thermal compatibility with the metal substrate.

The preparation method provided by the invention has the advantages of energy saving, environmental protection, low cost, and high process stability and controllability.

Description of the drawings

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments:

Figure 1 Thermal expansion curve of multi-phase particle modified enamel coating;

Figure 2 Microstructure morphology of the multi-phase particle modified enamel coating after phase transformation.

Detailed ways

The present invention will be further explained below in conjunction with specific embodiments, but the invention is not limited. The structures, proportions, sizes, etc. shown in the drawings of the description are only used to coordinate with the content disclosed in the description to facilitate familiarity with this invention. Those skilled in the art understand and read, but they are not intended to limit the implementation of the present invention, and therefore have no technical substantive significance. Any structural modifications, changes in proportions, or adjustments in size will not affect the performance of the present invention. The effect and the purpose that can be achieved should still fall within the scope of the technical content disclosed in the present invention.

Example 1

This embodiment describes an enamel coating that is highly thermally matched to a metal substrate and a preparation method thereof. First, the original single-phase quartz particles with D90 = 50 microns are ball milled for 40 hours to obtain fine quartz particles with fresh cleavage surfaces with D90 = 5 microns. Then the fine quartz particles are put into a high temperature furnace of 1050°C for activation for 3 minutes. Obtain core-shell structure multi-phase quartz particles, then mix the above-mentioned activated multi-phase quartz particles into the enamel glaze at a volume ratio of 55%, stir at 100 rpm for 5 minutes, spray on the substrate, and bake at 1000°C for 10 minutes. , the obtained thermal expansion curve of the enamel coating is shown in Figure 1, and the thermal expansion coefficient is increased by more than 60%.

Example 2

This embodiment describes an enamel coating that is highly thermally matched to a metal substrate and a preparation method thereof. First, the original single-phase quartz particles with D90 = 40 microns are ball milled for 20 hours to obtain fine quartz particles with fresh cleavage surfaces with D90 = 4 microns. Then the fine quartz particles are put into a high temperature furnace at 1000°C for activation for 4 minutes. Obtain core-shell structure multi-phase quartz particles, then mix the above-mentioned activated multi-phase quartz particles into the enamel glaze at a volume ratio of 45%, stir at 80 rpm for 3 minutes, brush on the base material, and bake at 1000°C for 60 minutes, the thermal expansion curve of the enamel coating obtained is shown in Figure 1. The thermal expansion coefficient at 200°C increases by more than 90%.

Example 3

This embodiment describes an enamel coating that is highly thermally matched to a metal substrate and a preparation method thereof. First, the original single-phase quartz particles with D90 = 15 microns are ball milled for 10 hours to obtain fine quartz particles with fresh cleavage surfaces with D90 = 3 microns. Then the fine quartz particles are put into a high temperature furnace of 1000°C for activation for 2 minutes. Obtain core-shell structure multi-phase quartz particles, and then mix the above-mentioned activated multi-phase quartz particles into the enamel glaze at a volume ratio of 45% and alumina 10%, stir at 150 rpm for 2 minutes, and spray on the base material, 1000 After firing at 180°C for 180 minutes, the thermal expansion curve of the enamel coating obtained is shown in Figure 1. The thermal expansion coefficient at 200°C increases by about 400%.

Example 4

This embodiment describes an enamel coating that is highly thermally matched to a metal substrate and a preparation method thereof. First, the original single-phase quartz particles with D90 = 10 microns are ball milled for 5 hours to obtain fine quartz particles with fresh cleavage surfaces with D90 = 3.5 microns. Then the fine quartz particles are put into a high temperature furnace of 1000°C for activation for 2 minutes. Obtain core-shell structure multi-phase quartz particles, and then mix the above-mentioned activated multi-phase quartz particles into the enamel glaze at a volume ratio of 45% and zirconium oxide 3%, stir at 50 rpm for 5 minutes, and spray on the base material, 1000 After firing at 1200°C for 1200 minutes, the thermal expansion curve of the enamel coating is shown in Figure 1. The thermal expansion coefficient at 200°C increases by about 550%. The microstructure morphology of the multi-phase particle modified enamel coating after phase transformation is shown in Figure 2. Matters not covered in the present invention are known technologies.

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art will understand that various changes, modifications, and substitutions can be made to these embodiments without departing from the principles and spirit of the invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (10)

1. An enamel coating that is highly thermally matched to a metal substrate, characterized in that: the enamel coating contains a core-shell structure complex quartz particle phase and a silicate enamel glaze parent phase. 2. The core-shell structure multi-phase quartz particle phase according to claim 1, characterized in that: the core-shell structure multi-phase quartz particle phase, the outer shell is composed of cristobalite or phosphoquartz phase, and the inner core is composed of quartz phase. 3. The enamel coating highly thermally matched with the metal substrate according to claim 1, characterized in that: the core-shell structure complex quartz particle size is 2-6 microns, and the initial core/shell size ratio of the particles is 100- 1000. 4. The enamel coating highly thermally matched with the metal substrate according to claim 1, characterized in that: the core-shell structure multi-phase quartz particle phase, the particle content of the core-shell structure multi-phase quartz particle phase is a volume fraction of 35 %-65%. 5. The enamel coating highly thermally matched with the metal substrate according to claim 1, characterized in that: the enamel coating, the enamel parent phase is a silicate glass phase, and in addition, the total volume fraction can contain no more than 25% ceramic phase particles such as alumina, zirconia, and chromium oxide. 6. A method for preparing an enamel coating that is highly thermally matched to a metal substrate according to claim 1, characterized in that: The specific preparation method is: ① First, ball mill the coarse original single-phase quartz particles to obtain fine quartz particles with fresh cleavage surfaces; ② Put the above-mentioned newly prepared fine quartz particles into a high-temperature furnace for activation and obtain the core and shell. Structural multi-phase quartz particles; ③ Mix the above-mentioned activated multi-phase quartz particles into the enamel glaze and spray or brush on the substrate; ④ Control the dissolution and phase transformation process of the multi-phase quartz particles by adjusting the firing temperature and time to obtain Highly thermally matched enamel coating to the metal substrate. 7. The method for preparing an enamel coating that is highly thermally matched to a metal substrate according to claim 6, characterized in that: the size of the original single-phase quartz particles is 10-50 microns, and the quartz particles obtained by ball milling and crushing have fresh cleavage surfaces. The size is controlled at 2-6 microns. 8. The method for preparing an enamel coating that is highly thermally matched to a metal substrate according to claim 6, characterized in that the temperature of the high-temperature activation furnace is 1000°C-1400°C, and the activation time is 2-10 minutes. 9. The method for preparing an enamel coating that is highly thermally matched to a metal substrate according to claim 6, characterized in that: the complex quartz particles are mixed into the enamel glaze using a slow stirring method, the rotation speed is 20-200 rpm, and the stirring time 2-5 minutes. 10. The method for preparing an enamel coating that is highly thermally matched to a metal substrate according to claim 6, characterized in that: the enamel firing temperature is 800°C-1000°C and the time is 10-1200min.