Low-cost high-temperature composite thermal insulation material and preparation method thereof

Abstract

The invention discloses a low-cost high-temperature composite thermal insulation material and a preparation method thereof, and relates to the technical field of thermal insulation materials. The material is composed of a fiber matrix layer and a high-emission coating, and the fiber matrix layer is of a five-layer laminated structure including a base layer (powder quartz fiber), a middle reinforcing layer (English micro fiber cloth), a main heat insulation layer (fly ash fiber), a reinforcing heat insulation layer (quartz continuous fiber fabric) and a coating bearing layer (high silica continuous fiber fabric). All the layers are sewn through alumina fiber threads to form a stable framework; the surface is coated with a SiC / ZrO2 composite high-emission coating, and integrated forming is achieved through a single spraying process. The fly ash fiber is used as a core raw material, the low-cost quartz fiber and the industrial solid waste are recycled, and the material cost is reduced by 40% or above; through optimization of the porosity of the fiber network and the synergistic effect of the SiC / ZrO2 coating, the heat insulation material has the advantages of excellent heat insulation, high temperature resistance and process simplification, and is suitable for the fields of aerospace, metallurgy, petrifaction and the like.

Description

Technical Field

[0001] The present application relates to the technical field of thermal insulation materials, and in particular to a low-cost high-temperature composite thermal insulation material and a preparation method thereof. Background Art

[0002] High-temperature thermal insulation materials are widely used in aerospace thermal protection, metallurgical furnace linings, petrochemical equipment insulation and other fields. At present, the mainstream materials are based on oxide fibers (such as alumina fibers, quartz fibers, etc.), and thermal insulation tiles are prepared by wet molding combined with high-temperature sintering processes, or thermal insulation felts are made by stitching high-temperature resistant fiber fabrics. However, the existing technology has significant defects: (1) The thermal insulation tiles need to be coated with a high-emissivity coating after the matrix is formed, which involves two high-temperature sintering processes (matrix sintering + coating sintering). The process is complex and energy-intensive; (2) In order to ensure high-temperature stability, the surface of the thermal insulation felt needs to use expensive materials such as high-purity quartz fibers and silicon carbide fibers, resulting in rising costs; (3) Traditional coating materials (such as single SiC coatings) have limited emissivity and are easily oxidized and peeled off at high temperatures. The above problems seriously restrict the large-scale application of high-temperature thermal insulation materials in low-cost scenarios (such as industrial kilns).

[0003] Therefore, there is an urgent need to develop a composite thermal insulation material that has excellent temperature resistance, high radiation heat dissipation capacity and low cost, and to simplify its preparation process. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects of existing high-temperature thermal insulation materials, such as complex preparation process, high cost and insufficient coating performance, and to provide a low-cost, high-temperature resistant composite thermal insulation material and its preparation method.

[0005] The following technical solutions are adopted:

[0006] The first aspect of the present invention provides a low-cost high-temperature composite thermal insulation material, which is composed of a fiber matrix layer and a high-emissivity coating, wherein the fiber matrix layer is composed of a coating bearing layer, a reinforced thermal insulation layer, a main thermal insulation layer, an intermediate reinforcement layer and a base layer, and is obtained by sewing alumina fiber wire.

[0007] Preferably, the base layer is composed of 15-25 parts by volume of quartz continuous fiber fabric; the intermediate reinforcement layer is composed of 10-15 parts by volume of Invitrogen cloth; the main insulation layer is composed of 50-60 parts by volume of fly ash fiber; the reinforcement insulation layer is composed of 5-15 parts by volume of powdered quartz fiber; and the coating bearing layer is composed of 3-10 parts by volume of high silica continuous fiber fabric.

[0008] Preferably, the mass ratio of the powdered quartz fiber to the fly ash powder fiber is 1:1.5; and the fiber diameter is 1-4 μm.

[0009] Preferably, the high-emission coating is a SiC / ZrO2 composite coating with a coating thickness of 50-200 μm.

[0010] A second aspect of the present invention provides a method for preparing the above-mentioned low-cost high-temperature composite thermal insulation material, comprising the following steps:

[0011] S1. quartz continuous fiber fabric, filament cloth, fly ash fiber, powdered quartz fiber, and high-silica fiber fabric are stacked and laid in sequence according to proportion, and then sewn with alumina fiber thread to obtain a fiber matrix layer.

[0012] S2. A low-cost, high-temperature composite thermal insulation material is obtained by coating the surface of the fiber matrix layer with a SiC / ZrO2 composite coating by spraying.

[0013] Preferably, the preparation step of the SiC / ZrO2 composite coating is to place SiC and ZrO2 powders in a 30% concentration silica sol solution, and then perform ball milling to mix them at a ball-to-material ratio of 3:1 to obtain the composite coating.

[0014] Beneficial effects

[0015] The present invention provides a low-cost, high-temperature composite thermal insulation material. Quartz fiber cloth, Invitrogen cloth, fly ash fiber, quartz fiber, and high-silica fiber cloth are laid sequentially, and then stitched together with alumina fiber threads to form a fiber matrix layer, avoiding the high-temperature sintering step. SiC and ZrO2 powders are evenly dispersed using a silica sol-based ball milling method to prepare a SiC / ZrO2 composite slurry. A high-emissivity coating is then applied to the fiber matrix layer via spraying, achieving a single-coating, integrated molding process. The synergistic effect of fly ash fiber and ultrafine quartz fiber reduces raw material costs while improving thermal insulation performance by optimizing the porosity of the fiber network. In the SiC / ZrO2 composite coating, the phase change toughening effect of ZrO2 inhibits high-temperature cracking of the coating, while the high infrared emissivity of SiC (>0.9) enhances radiative heat dissipation. These two factors work together to improve the coating's thermal shock resistance and durability.

[0016] The present invention uses fly ash fiber as the core raw material, combines low-cost quartz fiber and industrial solid waste resource utilization, and reduces material costs by more than 40%; by optimizing the fiber network porosity and the synergistic effect of the SiC / ZrO2 coating, it has the advantages of excellent thermal insulation, high temperature resistance and simplified process, and is suitable for aerospace, metallurgy, petrochemical and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The overall structure diagram of the present invention

[0018] Numbers in the figure: 1, high-emissivity coating; 2, fiber matrix layer; 2-1 coating bearing layer; 2-2 reinforced thermal insulation layer, 2-3 main thermal insulation layer; 2-4 intermediate reinforcement layer; 2-5 base layer. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be noted that the terms "vertical", "up", "down", "horizontal", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the present invention.

[0021] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0022] See also Figure 1 The present invention provides a technical solution: a low-cost high-temperature composite thermal insulation material and a preparation method thereof, comprising a high-emissivity coating 1 and a fiber matrix layer 2, wherein the fiber matrix layer is composed of a coating bearing layer 2-1, a reinforced thermal insulation layer 2-2, a main thermal insulation layer 2-3, an intermediate reinforcement layer 2-4 and a base layer 2-5, and the coating bearing layer 2-1, the reinforced thermal insulation layer 2-2, the main thermal insulation layer 2-3, the intermediate reinforcement layer 2-4 and the base layer 2-5 are sewn with alumina fiber thread.

[0023] The raw materials and composition ratio of the fiber matrix layer are as follows: the base layer is composed of 15-25 parts by volume of quartz continuous fiber fabric; the intermediate reinforcement layer is composed of 10-15 parts by volume of Invitrogen cloth; the main insulation layer is composed of 50-60 parts by volume of fly ash fiber; the reinforcement insulation layer is composed of 5-15 parts by volume of powdered quartz fiber; the coating bearing layer is composed of 3-10 parts by volume of high-silica continuous fiber fabric.

[0024] Example 1

[0025] Formula and volume (based on the total volume of the fiber matrix layer as 100%)

[0026] Base layer: 20% quartz continuous fiber fabric (silicon dioxide content ≥ 99%, fiber diameter 2μm)

[0027] Middle reinforcement layer: 12% Invitro woven fabric (aramid fiber braided, thickness 0.5mm)

[0028] Main insulation layer: 50% fly ash fiber (particle size ≤ 50μm, porosity 85%)

[0029] Reinforced insulation layer: 10% powdered quartz fiber (silicon dioxide content ≥ 95%, fiber diameter 1.5μm)

[0030] Coating bearing layer: 8% high silica continuous fiber fabric (silicon dioxide content ≥96%, fabric density 0.8g / cm 3 )

[0031] The specific preparation steps are as follows:

[0032] S1. Preparation of the fiber matrix layer: Lay the materials in the above proportions and secure them with alumina fiber strands (0.1 mm diameter) at 2 mm intervals. Heat-press at 150°C for 10 minutes at a pressure of 0.5 MPa to obtain the fiber matrix layer.

[0033] Preparation of SiC / ZrO2 Composite Coating: SiC powder (1 μm particle size) and ZrO2 powder (0.8 μm particle size) were mixed in a mass ratio of 2:1. A 30% silica sol solution was added, resulting in a ball-to-material ratio of 3:1. The mixture was ball-milled for 4 hours at 200 rpm.

[0034] S3. Preparation of composite thermal insulation material: The SiC / ZrO2 composite coating was sprayed on the fiber substrate layer prepared in S1. The spraying parameters were: spraying pressure 0.3 MPa, spray gun distance 20 cm, coating thickness 80 μm, and curing conditions were baking at 300 ° C for 1 hour.

[0035] Example 2

[0036] Formula and volume (based on the total volume of the fiber matrix layer as 100%)

[0037] Base layer: 18% quartz continuous fiber fabric (silicon dioxide content ≥ 99%, fiber diameter 2μm)

[0038] Middle reinforcement layer: 15% Invitro woven fabric (aramid fiber braided, thickness 0.5mm)

[0039] Main insulation layer: 55% fly ash fiber (particle size ≤ 50μm, porosity 85%)

[0040] Reinforced insulation layer: 8% powdered quartz fiber (silicon dioxide content ≥ 95%, fiber diameter 1.5μm)

[0041] Coating bearing layer: 4% high silica continuous fiber fabric (silicon dioxide content ≥ 96%, fabric density 0.8g / cm 3 )

[0042] The specific preparation steps are consistent with those in Example 1.

[0043] Example 3

[0044] Formula and volume (based on the total volume of the fiber matrix layer as 100%)

[0045] Base layer: 22% quartz continuous fiber fabric (silicon dioxide content ≥ 99%, fiber diameter 2μm)

[0046] Middle reinforcement layer: 10% Invitro woven fabric (aramid fiber braided, thickness 0.5mm)

[0047] Main insulation layer: 60% fly ash fiber (particle size ≤ 50μm, porosity 85%)

[0048] Reinforced insulation layer: 5% powdered quartz fiber (silicon dioxide content ≥ 95%, fiber diameter 1.5μm)

[0049] Coating bearing layer: 3% high silica continuous fiber fabric (silicon dioxide content ≥ 96%, fabric density 0.8g / cm 3 )

[0050] The specific preparation steps are consistent with those in Example 1.

[0051] Performance testing:

[0052] Thermal conductivity test: Thermal conductivity tester (GB / T 37796-2019)

[0053] Temperature resistance test: Fully automatic high temperature flexure tester: Xiangke GKZ-II (GB / T 28289-2012)

[0054] Mechanical properties test: Universal testing machine WEW-300B (GB / T 28289-2012)

[0055]

[0056] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A low-cost high-temperature composite thermal insulation material, characterized by: It consists of a fiber matrix layer and a high-emissivity coating, wherein the fiber matrix layer consists of a coating bearing layer, a reinforced thermal insulation layer, a main thermal insulation layer, an intermediate reinforcement layer and a base layer.

2. The low-cost high-temperature composite thermal insulation material according to claim 1, characterized in that: The base layer is composed of 15-25 parts by volume of quartz continuous fiber fabric; the intermediate reinforcement layer is composed of 10-15 parts by volume of Invitrogen cloth; the main insulation layer is composed of 50-60 parts by volume of fly ash fiber; the reinforcement insulation layer is composed of 5-15 parts by volume of powdered quartz fiber; and the coating bearing layer is composed of 3-10 parts by volume of high-silica continuous fiber fabric.

3. The low-cost high-temperature composite thermal insulation material according to claim 1, characterized in that: The mass ratio of the powdered quartz fiber to the fly ash powder fiber is 1:1.5; and the fiber diameter is 1-4 μm.

4. The low-cost high-temperature composite thermal insulation material according to claim 1, characterized in that: The high-emission coating is a SiC / ZrO2 composite coating with a coating thickness of 50-200 μm.

5. A method for preparing a low-cost high-temperature composite thermal insulation material, characterized by: The following steps are involved: S1. The quartz continuous fiber fabric, Yingwei Lun cloth, fly ash fiber, powder quartz fiber, high silica continuous fiber fabric were stacked in proportion and sutured with alumina fiber thread; A fiber matrix layer is obtained. S2. A low-cost, high-temperature composite thermal insulation material is obtained by coating the surface of the fiber matrix layer with a SiC / ZrO2 composite coating by spraying.

6. The SiC / ZrO2 composite coating according to claim 5, wherein the preparation thereof comprises the following steps: SiC and ZrO2 powders were placed in a 30% concentration silica sol solution, and then ball milled at a ball-to-material ratio of 3:1 to obtain a composite coating.

Images