Application of ceramic fiber products

Maximum characteristics of ceramic fiber:

(1) The thermal conductivity is low, only 0.03 W/(m · K) at normal temperature, and 1/5 of clay brick at 1000 ℃.

(2) The product density is small, generally between 64 and 500 kg/m3.

(3) The thermal capacity is low, only 1/72 of that of refractory bricks and 1/42 of that of lightweight bricks.

(4) Good processing performance, soft and easy to cut fiber, strong continuity, easy to wind.

(5) It has good sound absorption performance and can be used as high temperature silencing material.

(6) Good chemical stability, except for strong alkali, fluorine and phosphate, it is almost free from chemical erosion.

(7) Good thermal shock resistance.

(8) Good insulation performance, volume resistivity at room temperature is 1 × 1013 Ω · cm, volume resistivity is 6 at 800 ℃ × 108Ω·cm。

(9) Ceramic fiber pair wavelength 1.8~6.0 μ The light wave of m has high reflectivity.

Ceramic fiber raw cotton is usually processed into various types of ceramic fiber products for all walks of life. The most important use of ceramic fiber products is thermal insulation in high temperature environment. The application scope covers metallurgy, machinery, electronics, ceramics, glass, chemical industry, automobile, building materials, light industry, military industry, shipbuilding, aerospace and other fields.

At present, ceramic fiber products include carpet, felt, board, paper, cloth, belt, rope, coil, tile, module, profiled parts, plastic, coating, coating, castable, etc.

1. Ceramic fiber raw cotton

Ceramic fiber cotton is made by melting raw materials at high temperature in a resistance furnace, and is produced by the process of blowing or spinning into fiber, with a diameter of 2-5 μ m. The length is mostly 30-250 mm.

The fiber surface of ceramic fiber cotton is smooth and cylindrical, and its cross section is usually circular. Its structure is characterized by high porosity (generally more than 90%), and large pore size and specific surface area. Because the air in the pores has a good thermal insulation effect, the size of the pore size and the nature of the pores (open or closed pores) in the fibers have a decisive impact on their thermal conductivity. In fact, the internal structure of ceramic fibers is a mixed structure composed of solid fibers and air, and its microstructure is characterized by that both the in-phase and gas phases exist in the form of continuous phases. Therefore, in this structure, the solid material exists in the form of fiber and forms a continuous phase skeleton, while the gas phase continuously exists in the framework gap of the fiber material. It is precisely because of this structure that ceramic fiber has higher porosity, larger pore size and specific surface area, so that ceramic fiber has excellent thermal insulation performance and smaller bulk density.

Ceramic fiber cotton is a neutral and slightly acidic material. In addition to reacting with strong acids and alkalis, it will not be eroded by other weak bases, weak acids, water, oil and steam, and will not be soaked with lead, aluminum and copper. It has excellent flexibility and elasticity. The density of ceramic fiber is relatively small, which is more than 75% lighter than the light insulating brick furnace lining, 90% - 95% lighter than the light castable furnace lining, the thermal conductivity is about 1/8 of the light clay brick, and 1/10 of the light heat-resistant lining (castable), and the thermal capacity is only about 1/10 of the light insulating lining and light castable lining, which greatly reduces the energy consumption and has significant energy saving and heat storage effect. At the same time, ceramic fiber has the characteristics of simple construction, no need for oven drying, short construction period and simple installation. Ceramic fiber cotton is the main raw material for other ceramic fiber products. It can also be directly used as expansion joint filling, furnace wall insulation and sealing materials for industrial furnaces according to the classification temperature.

2. Ceramic fiber coating system

The manufacturing method of ceramic fiber coating material is to naturally settle the bulk ceramic fiber on the mesh belt of the cotton collector to form a uniform cotton blank. The dry needled blanket without adhesive is obtained by needle-punching process. The blanket is soft and elastic, with high tensile strength and excellent processing and construction performance. It is one of the most widely used ceramic fiber products. According to the different process, the ceramic fiber coating system can be divided into two categories: spinning and blowing.

The ceramic fiber coating system is applicable to the door sealing, furnace mouth curtain, kiln top insulation of various thermal insulation industrial furnaces: high-temperature flue, air duct bushing, expansion joint: petrochemical equipment, containers, pipes, high-temperature insulation and heat preservation; Protective clothing, gloves, headsets, helmets, boots, etc. under high temperature environment; Automobile engine heat shield, heavy oil engine exhaust pipe wrapping, high-speed racing composite brake friction pad, nuclear power, steam turbine heat insulation; Heat treatment and insulation of heating elements; Sealing fillers and gaskets for pumps, compressors and valves conveying high-temperature liquids and gases: high-temperature electrical insulation: fireproof joint products such as fire doors, fire curtains, fire blankets, spark pads and thermal insulation covers; Thermal insulation, thermal insulation materials and brake friction pads for aerospace and aviation industries; Thermal insulation and packaging of cryogenic equipment, containers and pipes, thermal insulation and fire insulation of important places such as archives, vaults and safes in high-end buildings, and automatic fire curtains for fire protection.

3. Ceramic fiber profiled parts

Ceramic fiber profiled parts are made of high-quality ceramic fiber cotton by vacuum molding process. It can be made into special-shaped products with superior high temperature performance, rigidity and self-supporting strength. All special-shaped products have low shrinkage within their service temperature range, and maintain the characteristics of high heat insulation, light weight and impact resistance. Unburned materials are easily cut into mechanical processing. In the process of use, the product has good anti-wear and peeling performance, and is not wetted by most molten metal.

Ceramic fiber profiled parts include tubular, conical, domed and square box. Most profiled products are produced according to customers' requirements, such as casting caps and sleeves for non-ferrous metal industry, vacuum forming fire holes for petrochemical industry, etc.