阅读说明：本技术 一种梯度涂层预应力增强建筑陶瓷制品及其制备方法 (Gradient coating prestress reinforced building ceramic product and preparation method thereof ) 是由 孙熠 包亦望 李月明 沈宗洋 于 2019-11-04 设计创作，主要内容包括：本发明公开了一种梯度涂层预应力增强建筑陶瓷制品,由建筑陶瓷坯体、以及涂覆于坯体表面的涂层构成；所述涂层至少为二层,由坯体底部至表面的各涂层其热膨胀系数递减、弹性模量递增而形成梯度涂层。此外,还公开了上述梯度涂层预应力增强建筑陶瓷制品的制备方法。本发明通过在建筑陶瓷坯体表面,采用表层匹配法、通过叠加的方式形成热膨胀系数递减、弹性模量递增的梯度涂层,为建筑陶瓷坯体提供预应力,从而显著提高了建筑陶瓷的强度。(The invention discloses a gradient coating prestress reinforced building ceramic product, which consists of a building ceramic blank and a coating coated on the surface of the blank; the coating is at least two layers, and the thermal expansion coefficient and the elastic modulus of each coating from the bottom to the surface of the blank are gradually decreased to form a gradient coating. In addition, a preparation method of the gradient coating prestress reinforced building ceramic product is also disclosed. The invention forms the gradient coating with the decreasing thermal expansion coefficient and the increasing elastic modulus by adopting a surface matching method and a superposition mode on the surface of the architectural ceramic blank, thereby providing prestress for the architectural ceramic blank and obviously improving the strength of the architectural ceramic.)

1. A gradient coated prestressed reinforced architectural ceramic article characterized by: the building ceramic coating is composed of a building ceramic blank and a coating coated on the surface of the blank; the coating is at least two layers, and the thermal expansion coefficient and the elastic modulus of each coating from the bottom to the surface of the blank are gradually decreased to form a gradient coating.

2. A method of making a gradient coated pre-stressed reinforced architectural ceramic article in accordance with claim 1, comprising the steps of:

(1) separately preparing the slurries for each coating

The slurry of each coating consists of respective base material and binder solution, and the weight ratio of the base material to the binder solution is 1: 1.0-1.6; preparing the components of the base material, adding the binder solution as a ball milling medium, carrying out ball milling mixing, and sieving to obtain slurry;

(2) applying slurry serving as a bottom coating on the surface of the architectural ceramic blank, drying in the shade at room temperature to form a coating with a large thermal expansion coefficient and a small elastic modulus, then repeating the same method, and continuously applying slurry of other layers to form a gradient coating with a decreasing thermal expansion coefficient and an increasing elastic modulus from the bottom of the blank to the surface, so as to obtain a ceramic blank with the gradient coating;

(3) and sintering the ceramic blank with the gradient coating, and naturally cooling to room temperature to obtain the co-sintered prestress-reinforced building ceramic product.

3. The method of making a gradient coated pre-stress reinforced architectural ceramic article according to claim 2, wherein: the gradient coating is composed of a base coating and a face coating.

4. A method of making a gradient coated pre-stress reinforced architectural ceramic article in accordance with claim 3, wherein: the slurry of the bottom coating comprises a bottom base material and a bottom binder solution, wherein the bottom base material comprises 5-25 wt% of alumina micropowder, 35-65 wt% of quartz, 20-40 wt% of dolomite and 5-15 wt% of spodumene, and the bottom binder solution is a solution of one or a combination of CMC, PVA and PVB, and has a concentration of 1-3 wt%; the face coating slurry comprises a face base material and a face binder solution, wherein the face base material comprises 5-15 wt% of alumina micropowder, 35-60 wt% of quartz, 0-12 wt% of dolomite, 0-10 wt% of calcined talc, 0-10 wt% of industrial zinc oxide and 6-20 wt% of spodumene, and the face binder solution is a solution of one or a combination of CMC, PVA and PVB, and the concentration of the face binder solution is 1-5 wt%.

5. The method of making a gradient coated pre-stress reinforced architectural ceramic article according to claim 4, wherein: the granularity of the alumina micro powder is 800-1500 meshes.

6. The method of making a gradient coated pre-stress reinforced architectural ceramic article according to claim 2, wherein: and (2) applying slurry of a bottom coating and slurry of a face coating on the upper surface and the lower surface or all the surfaces of the building ceramic body in the step (2).

7. A method of manufacturing a gradient coated pre-stress reinforced building ceramic article according to claim 3 or 4 or 5 or 6, characterized in that: the thickness of the face coating is less than that of the bottom coating; the total thickness of the gradient coating/the thickness of the ceramic body is less than 0.05.

8. The method of manufacturing a gradient coated pre-stress reinforced building ceramic article according to claim 2 or 3 or 4 or 5 or 6, characterized in that: and (4) sintering at 1180-1230 ℃, wherein the heating rate is 2-6 ℃/min.

9. The method of manufacturing a gradient coated pre-stress reinforced building ceramic article according to claim 2 or 3 or 4 or 5 or 6, characterized in that: the ceramic body is made of, by weight, 0-20% of Datong sandstone, 15-30% of quartz, 0-15% of purple wood knot, 25-50% of feldspar and 0-15% of Zhangvillage soil.

Technical Field

The invention relates to the technical field of ceramic materials, in particular to a gradient coating prestress-enhanced building ceramic product and a preparation method thereof.

Background

Along with the improvement of living standard and aesthetic standard of people, the size specification of the architectural ceramics is bigger and bigger, and the requirements on the service cycle and the bending strength of the architectural ceramics are higher and higher. In addition, the architectural ceramic industry belongs to three high industries with high pollution, high energy consumption and high resource consumption, not only consumes a large amount of natural resources and energy, but also seriously hinders the sustainable development of the ceramic industry in China, and simultaneously, seriously pollutes and destroys the living environment of human beings, influences the normal work and life of people, and has contradiction with the development concept of ecological civilization construction and ecological environment protection in China. If the strength of the architectural ceramic can be effectively improved, the energy consumption and resources (thinning of the architectural ceramic) of a unit product can be reduced inevitably, so that the raw materials and energy consumption of the architectural ceramic are greatly saved, and the resource utilization rate is improved. Therefore, how to increase the strength of the ceramic to meet the common needs of the industries and follow the national strategy of energy conservation and consumption reduction is a major development direction of the architectural ceramic industry in recent years.

The prestress enhancement design is that compressive stress is introduced into a material or a component in advance so as to offset an external tensile stress load, so that the strain amount of the matrix cracked under the tension is increased, and the aims of improving the breaking strength, reliability and durability of the material are fulfilled. The prestress reinforcement design is widely applied to the field of concrete structures and toughened glass (prestressed glass), and due to the complexity of ceramic materials, how to realize the reinforcement of prestressed ceramic products is the subject of urgent research at present, and simultaneously, the prestress reinforcement design has great and attractive prospects in the aspects of resource and energy conservation and the like of the architectural ceramic material industry.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a gradient coating prestress reinforced building ceramic product, which adopts a surface matching method and a superposition mode to form a gradient coating with a gradually decreased thermal expansion coefficient and an gradually increased elastic modulus on the surface of a building ceramic blank so as to provide prestress for the building ceramic blank and obviously improve the strength of the building ceramic. The invention also aims to provide a preparation method of the gradient coating prestress reinforced building ceramic product.

The purpose of the invention is realized by the following technical scheme:

the invention provides a gradient coating prestress reinforced building ceramic product, which consists of a building ceramic blank and a coating coated on the surface of the blank; the coating is at least two layers, and the thermal expansion coefficient and the elastic modulus of each coating from the bottom to the surface of the blank are gradually decreased to form a gradient coating.

The invention adopts a surface matching method to form a gradient coating with gradient thermal expansion coefficient and elastic modulus (the thermal expansion coefficient of a blank is more than that of a bottom coating, the thermal expansion coefficient of an n-layer coating is more than that of a surface coating, the elastic modulus of the blank is less than that of the bottom coating, the elastic modulus of the n-layer coating is less than that of the surface coating) in a superposition mode, and provides gradient prestress for the blank, thereby realizing the remarkable improvement of the breaking strength of the blank.

The other purpose of the invention is realized by the following technical scheme:

the preparation method of the gradient coating prestress reinforced building ceramic product provided by the invention comprises the following steps:

(1) separately preparing the slurries for each coating

The slurry of each coating consists of respective base material and binder solution, and the weight ratio of the base material to the binder solution is 1: 1.0-1.6; preparing the components of the base material, adding the binder solution as a ball milling medium, carrying out ball milling mixing, and sieving to obtain slurry;

(2) applying slurry serving as a bottom coating on the surface of the architectural ceramic blank, drying in the shade at room temperature to form a coating with a large thermal expansion coefficient and a small elastic modulus, then repeating the same method, and continuously applying slurry of other layers to form a gradient coating with a decreasing thermal expansion coefficient and an increasing elastic modulus from the bottom of the blank to the surface, so as to obtain a ceramic blank with the gradient coating;

(3) and sintering the ceramic blank with the gradient coating, and naturally cooling to room temperature to obtain the co-sintered prestress-reinforced building ceramic product.

Further, the gradient coating of the invention adopts two layers of superposition, namely, the gradient coating is composed of a bottom coating and a face coating.

In the scheme, the slurry of the bottom coating comprises a bottom base material and a bottom binder solution, wherein the bottom base material comprises 5-25 wt% of alumina micropowder, 35-65 wt% of quartz, 20-40 wt% of dolomite and 5-15 wt% of spodumene, and the bottom binder solution is a solution of one or a combination of CMC, PVA and PVB, and has a concentration of 1-3 wt%; the face coating slurry comprises a face base material and a face binder solution, wherein the face base material comprises 5-15 wt% of alumina micropowder, 35-60 wt% of quartz, 0-12 wt% of dolomite, 0-10 wt% of calcined talc, 0-10 wt% of industrial zinc oxide and 6-20 wt% of spodumene, and the face binder solution is a solution of one or a combination of CMC, PVA and PVB, and the concentration of the face binder solution is 1-5 wt%.

Furthermore, the granularity of the alumina micro powder is 800-1500 meshes.

In the scheme, the building ceramic body is a brick body with the thickness of 6-15 mm, and the slurry of the bottom coating and the slurry of the face coating are applied to the upper surface and the lower surface or all the surfaces of the building ceramic body in the step (2). The thickness of the face coating is less than that of the bottom coating; the total thickness of the gradient coating/the thickness of the ceramic body is less than 0.05. And (4) sintering at 1180-1230 ℃, wherein the heating rate is 2-6 ℃/min, and the heat preservation time is 20-40 min.

Furthermore, the ceramic body comprises, by weight, 0-20% of large common sandstone, 15-30% of quartz, 0-15% of purple wood knot, 25-50% of feldspar and 0-15% of Zhang village soil.

The invention has the following beneficial effects:

(1) the invention adopts the prestress gradient coating material on the surface of the building ceramic blank to control the difference of the thermal expansion coefficient and the elastic modulus between the gradient coating and the blank, and forms stronger gradient compressive stress on the surface in the process of cooling from high temperature to normal temperature after the building ceramic is sintered. Different from the prior art residual stress toughening and reinforcing method, the invention applies the pre-stress to the ceramic blank by forming the coating with the gradient thermal expansion coefficient and the elastic modulus, increases the strain from stress to damage of the ceramic blank, greatly improves the strength (the improvement rate of the flexural strength is more than 95 percent) and the integrity of the building ceramic product, and improves the safety of practical use.

(2) The raw materials of the invention are nontoxic and pollution-free, and are environment-friendly, and the whole preparation process is green, clean and pollution-free.

(3) The invention has simple and easy process, low raw material price and easy industrial application and popularization.

Drawings

The invention will now be described in further detail with reference to the following examples and the accompanying drawings:

FIG. 1 is a XRD test result of a bottom coating of a pre-stressed reinforced architectural ceramic article according to an embodiment of the present invention;

figure 2 is a XRD test result of the face coating of the pre-stressed reinforced architectural ceramic article of the present invention.

Detailed Description

The invention provides a gradient coating prestress reinforced building ceramic product, which consists of a building ceramic blank and a coating coated on the surface of the blank; the coating is a gradient coating formed by a bottom coating and a face coating, namely the thermal expansion coefficient of a blank is larger than the thermal expansion coefficient of the bottom coating and larger than the thermal expansion coefficient of the face coating, and the elastic modulus of the blank is smaller than the elastic modulus of the bottom coating and smaller than the elastic modulus of the face coating.

The slurry of the bottom coating and the slurry of the face coating are respectively composed of a base material and a binder solution, and the weight ratio of the base material to the binder solution is 1: 1.0-1.6.

In the slurry of the bottom coating, the raw material composition of the bottom base material is 5-25 wt% of alumina micropowder, 35-65 wt% of quartz, 20-40 wt% of dolomite and 5-15 wt% of spodumene, and the bottom binder solution is one or a combination of CMC, PVA and PVB, and the concentration of the bottom binder solution is 1-3 wt%.

In the slurry of the face coating, the raw materials of the face base material comprise 5-15 wt% of alumina micropowder, 35-60 wt% of quartz, 0-12 wt% of dolomite, 0-10 wt% of calcined talc, 0-10 wt% of industrial zinc oxide and 6-20 wt% of spodumene, and the face binder solution is one or a combination of CMC, PVA and PVB, and the concentration of the face binder solution is 1-5 wt%.

The slurry composition of the coatings of the various embodiments of the present invention are shown in table 1.

Table 1 slurry composition of coatings of various examples of the invention

Is given by weight

The building ceramic body used in the embodiment of the invention comprises the following raw materials in parts by weight: 13 wt% of Datong sandstone, 25 wt% of quartz, 12 wt% of purple wood knot, 38 wt% of feldspar and 12 wt% of Zhangcun soil. The preparation method comprises the following steps: mixing the raw materials according to the composition of the green body, carrying out wet ball milling (mixing, ball and water are 1: 2: 0.5), sieving to remove iron (0.1 percent of sieve residue of a 250-mesh sieve), granulating, and carrying out press molding (with the water content of 7 percent), carrying out biscuit firing at the temperature of 450 ℃, and cooling to obtain the building ceramic green body with the length of 100mm, the width of 80mm and the thickness of 6 mm.

The preparation method of the gradient coating prestress reinforced building ceramic product comprises the following steps:

(1) separately preparing a base coat slurry and a face coat slurry

Preparing the components of the base material at the bottom, adding a base binder solution serving as a ball milling medium, performing ball milling and mixing (the ratio of the base material to balls is 1: 2), and sieving to obtain slurry of the bottom coating; similarly, preparing the slurry of the face coating;

(2) applying slurry of a bottom coating on the upper surface and the lower surface (or all surfaces) of the architectural ceramic blank by adopting a glaze spraying method, drying in the shade at room temperature to form the bottom coating, and then applying slurry of a face coating on the bottom coating by repeating the same method to obtain a ceramic blank with a gradient coating; wherein, the thickness of the face coating is less than that of the bottom coating, and the total thickness of the gradient coating/the thickness of the ceramic blank is less than 0.05;

(3) and heating the ceramic blank with the gradient coating at the speed of 2-6 ℃/min, sintering at the temperature of 1180-1230 ℃, keeping the temperature for 20-40 min, and naturally cooling to room temperature to obtain the co-sintered prestress-reinforced building ceramic product.

The process parameters of the preparation method of each example of the invention are shown in table 2.

TABLE 2 Process parameters for the preparation of the architectural ceramic articles of the examples of the present invention

The co-sintered prestressed reinforced building ceramic product prepared by the embodiments of the invention has a water absorption rate of less than 1%; as shown in fig. 1, the main crystal phase of the bottom coating after firing is cordierite, spinel; as shown in fig. 2, the main crystal phases of the face coating after firing were cordierite, spinel, anorthite. The architectural ceramic products obtained without applying the coating material to the architectural ceramic green bodies of the above examples and without changing other conditions were used as comparative examples corresponding to the examples. Table 3 shows the co-sintered prestressed reinforced building ceramic products manufactured according to the embodiments of the present invention and the flexural strengths of the respective comparative examples.

TABLE 3 flexural Strength of the architectural ceramic articles produced in the examples according to the invention and comparative examples