JPS5891082A - Heat radiative ceramic coating composition and use - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a heat-radiating ceramic composition and a coating material for the interior of an industrial heating furnace (i.e., the refractory wall of the furnace and the metal structure inside the furnace) having heat-radiating properties. Regarding the method used as

BACKGROUND ART Heat-resistant paints for coating metal surfaces and compositions for coating internal furnace wall surfaces that make full use of heat radiation have been known.

Furthermore, when indirect heat treatment is performed using a metal structure inside the furnace, absorption of the refractory material on the inside wall of the furnace, re-emission,
It is also a well-known fact that the thermal conductivity, absorption and re-radiation properties of the metal structures in the furnace on the heat-receiving surface must also be improved. However, conventional coatings with heat radiation properties cause poor adhesion and peel off after 1~ even if they are coated on the metal structures inside the furnace.Therefore, only the inner walls of the heating furnace can be coated, and as a result, the surfaces of the metal structures inside the furnace It is not possible to obtain sufficient thermal energy that is absorbed from the structure, conducted through the walls of the structure, and re-radiated to the heated object placed inside the structure.

Therefore, the object of the present invention is to create a heat-radiating ceramic composition that not only has good thermal conductivity, heat resistance, and heat radiation characteristics, but also has good adhesion that follows the expansion and contraction of metal due to heating and cooling. It's about finding out.

As a result of research, this problem could be solved by the following composition.

a) 40-75% by weight of silicon carbide as a heat radiating material, b) 15-405-40 parts by weight silicon 3-20 parts, phosphate 5-20 parts, chromium oxide 2-10 parts by weight C) 2 to 10 parts of tantalum carbide and 5 to 20 parts of aluminum powder (however, the sum of these compounds is always 100 parts by weight), a heat radiation aid and a binder, and C) 10 to 35 parts of aluminum powder. 1 to 10 parts by weight of aluminum oxide, 5 to 15 parts of glass powder, 3 to 15 parts of zirconium oxide, 1 to 10 parts of silicon dioxide, 1 to 10 parts of magnesium oxide, and 1 to 10 parts of iron oxide. (However, the total of these compounds is always 100 parts.) Consists of additives that increase adhesion and coating bond strength, and the sum of components a), b) and C) 1. A thermally emissive ceramic coating composition, characterized in that it has a 100% weight ratio.

Silicon carbide as the heat radiating material of component a) has a particularly high emissivity (at a temperature of 20-800°C, the total emissivity is 0.92
), the amounts used are components a), b) and C) (hereinafter,
Abbreviated as all ingredients. ) must be in the range of 40 to 75 1t% of the total weight. If the number is more than 75, it becomes difficult to follow the coefficient of thermal expansion of metal, especially when the composition is used as a coating, causing the coating to peel off. If the weight is increased by 40% or less, the thermal radiation properties and thermal conductivity of the coating will be significantly inferior, making it impossible to obtain the desired radiant energy.

The component b), which acts as a heat radiation aid and a binder, should be present in an amount of 15 to 405 to 40 parts by weight based on the total of all components. b) The individual compounds in the total composition and their reciprocal ratios are silicon nitride 3 to 20 superimposed parts, phosphate 5
~20 parts by weight, 2 to 10 parts by weight of chromium oxide, 2 to 10 parts by weight of tantalum carbide, and 5 to 20 parts by weight of aluminum powder (however, the total of these compounds is always 100 parts by weight)1, If the ratio of each compound constituting component b) exceeds the above range, desired heat radiation characteristics cannot be obtained.

If the amount of silicon nitride is less than 1 part by 3 parts, the airtightness of the 4 parts will be impaired and the life of the heat radiation property will be significantly reduced. Furthermore, if the amount of phosphate is less than 5 layers, the adhesive strength to the coating substrate will decrease.

If the amount of chromium oxide is double weighed, the tantalum carbide is double weighed, and the aluminum powder is less than 5 parts by weight, the desired heat conduction properties cannot be obtained and the adhesion strength to the object to be coated is poor.

Next, component C) must be in an amount of 10 to 350 to 35 parts by weight of the total of all components, and the individual compounds that make up component c) include 5 parts by weight of magnesium oxide, aluminum oxide, iron oxide, and silicon dioxide. 10 parts by weight each, zirconium oxide and glass powder should not exceed 15 parts by weight each.

If the amount of each of these components exceeds a predetermined range, it will be difficult to obtain a fired coating layer of the heat radiator with high airtightness.

Aluminum oxide, magnesium oxide, iron oxide and silicon dioxide each contain 1 part by weight (lζ) of the tile, and if zirconium oxide and glass powder each do not reach 3 parts by weight (lζ), a stable composition with high adhesive strength is used. cannot be obtained.

The coating amount of the coating composition of the present invention on the furnace inner wall is about 1.5 to 2.
, 0'fln2, and the amount of coating on the metal structures inside the furnace is optimally about 0.5 to 1.0 kg/m.

The present invention further relates to a method of using the thermally emissive ceramic coating composition described above. Furthermore, when applying the composition of the present invention to a substrate, if approximately 10 to 15% by weight (based on the total amount of the composition) of water is additionally mixed into the composition ((, coating It was found that workability was improved.

If scale is observed on the metal furnace internals as a pre-coating treatment, it is necessary to remove it using a twister plan or the like.

In one particularly advantageous embodiment, the coating composition of the invention provides a heat-resistant coating for refractory walls and metal structures in furnaces (4. Coating compositions containing water in the proportions indicated above) After applying the material, the temperature was increased by 100°C to lσ for 1 hour +!
: There is a method of heating to 400°C and then heating to 600°C for 2 hours to bake in close contact.

When the coating composition of the present invention is made into a coating in this way, it has a heat resistance of 1850° CJ or higher. In order to achieve high thermal emissivity, it saves all the thermal energy. For example, by applying the entire coating composition of the present invention to an indirect heating furnace, the heating time of the metal structure in the furnace on the heat-receiving surface was shortened by 41.6 times, and the thermal energy at that time was saved by 20%, 7''.

Next, one mode of using the thermal radiation ceramic coating composition of the present invention for coating an indirect heating furnace will be explained with reference to the accompanying drawings: Figure 1 is a schematic diagram of the indirect heating furnace, and (1) is a diagram showing the use of the heat radiation ceramic coating composition of the present invention for coating an indirect heating furnace. A heating furnace, (2) a resistance heating element, (3) a metal structure inside the furnace, and (4) a container containing heat medium oil.

FIG. 2 is a cross-section of the refractory material for the inner wall of the heating furnace. (5) shows the inner side of the furnace coated with the heat radiation ceramic coating composition of the present invention.

FIG. 6 is a cross-sectional view of a metal structure (boiler tube) in a furnace completely coated with the thermal radiation lamic coating composition of the present invention.

In such an indirect heating furnace, when an electric current is passed through the resistance heating element (2), heat is generated inside the furnace (1), and the metal structure (boiler tube) inside the furnace (3) then rises. The heating medium oil existing inside the heating chamber is heated and circulates with the heating medium oil in the container (4), and the temperature of the heating medium oil in the container rises.

Figure 4 is a graph of the atmospheric temperature inside the heating furnace, comparing the case where the refractory inner wall of the heating furnace and the metal structure inside the furnace are completely coated with the heat radiating ceramic composition of the present invention (solid line) and when they are not coated (dashed line). This is a graph showing.

FIG. 5 is a comparison graph showing the surface temperature of the metal structure in the heating furnace versus the rate of increase in heat.

FIG. 6 is a comparison graph showing the rate of increase in internal temperature of the metal structure in the heating furnace.

FIG. 7 is a comparison graph showing the rate of temperature rise of heat transfer oil.

As is clear from the comparison of these figures 4 to 7, the thermal radiation ceramic coating composition of the present invention was coated on the furnace inner wall surface.
When coating the metal structures inside the furnace, the time is reduced by 33.5 times in terms of the rate of increase in ambient temperature, and the time is reduced by 41.6% in terms of the surface temperature of the metal structures in the furnace minus the rate of rise.
This will save time.

The internal temperature of the metal structure inside the furnace - rate of increase was also 33.
The time of 3q6 is shortened, and the temperature rise rate of the heat medium oil, which is the final heated material, is shortened by 25%.

In this way, as is clear from the comparison before and after coating in the same heating furnace, the thermal radiation ceramic coating composition of the present invention can be applied to the refractory material on the inner wall of the heating furnace as well as the metal structures in the furnace (by p-coating). It was confirmed that all the results showed good results.

Next, the present invention will be explained in more detail with reference to the following examples.

Example 1 Silicon carbide 45.0 parts by weight, silicon nitride 31 parts by weight Aluminum phosphate 120 parts by weight, chromium oxide 60 parts by weight Tantalum carbide 5.0 parts by weight, aluminum powder 60 parts by weight Aluminum oxide 70 parts by weight , i
Magnesium t chloride 20 parts by weight Iron oxide 4.0
Heavy deposition part, glass powder 5.0 parts by weight zircon oxide
A composition of 60 parts by weight and 20 parts by weight of silicon dioxide was mixed, an additional 15 parts by weight of water was added, and the refractory material on the inner wall of the heating furnace was coated with a coating of about 0.8 l by spray paint. Paint the manufactured structure (l''!-approximately 0.34 degrees with a brush. Heat to 400°C for 4 hours at 100"C every hour, then bake at 600°C for 2 hours to harden the adhesive.) I do.

For comparison purposes, tests were conducted before and after coating the thermally emissive ceramic coating composition.

The temperature rise rate of the furnace atmosphere was reduced by 35 times, and the temperature rise rate of the heating medium oil of the object to be heated (t) was reduced by 25.5 times.

At this time, thermal energy was reduced by 20%.

Example 2 Silicon carbide 65 parts by weight, nitriding element 5
Parts by weight Atubenium phosphate 5 parts by weight, Chromium oxide
2 parts by weight Tantalum carbide 6 parts, aluminum powder 8 parts by weight Aluminum 1 part; bone part, magnesium oxide 1 part by weight Iron oxide 6 parts by weight, glass powder 6 parts by weight Zirconium oxide 6 parts by weight, and F dioxide The procedure of Example 1 to Example 1 was repeated using a coating composition consisting of a single layer of nitrogen.

The rate of increase in ambient temperature IW was reduced by 69 coefficients, and the rate of increase in the temperature of the heating medium oil of the object to be heated was reduced by 27 coefficients. At this time, the thermal energy was saved by 22%.5. Example 3 The method of Example 1 was repeated using mixtures of various compositions. All of these have been confirmed with good results. Table 1 shows the raw material composition and effects.

Part 1

[Brief explanation of the drawing]

Figure 1 is a sketch of an indirect 710 thermal furnace, and Figures 2 and 3 show the inner wall of the furnace, the metal structure inside the furnace, and the thermal radiation ceramic coating composition of the present invention. Figures 4 to 7 show a comparison between the presence and absence of the coating composition of the present invention, and Figure 4 shows the atmospheric temperature in the heating furnace, Figure 5 shows the internal temperature of the metal structure in the furnace, and Figure 6 shows the comparison between the presence and absence of the coating composition of the present invention. is the inner surface temperature of the metal structure inside the furnace, and Fig. 7 is a graph showing the relationship between each temperature rise time and heating time of the heat transfer oil. The symbols in Figs. 1 to 3 have the following meanings. ( 1)... Fireproof insulation brick, (2)... Resistance heating element, (3)... Metal structure inside the furnace, (4)... Heat transfer oil container, (5)... Coating composition. 427-1 Figure 4 Figure 4 Figure 2 Figure 3 Figure 0 20 40 60 80 100 120
) Fig. 5 Fig. 6 0 20 40 60 80 100 1201 Fj't < Min. I 1
%"l CA \) 1981 1 Sword/& ++ Commissioner Shima of the Patent Office 1) Haruki Tono1, Indication of the case 1987 Patent Application No. 187695 Method 3, Person making the amendment Relationship to the case Applicant's name Sanku Kasei Kogyo Co., Ltd. (name: fl.) 4. Agent 1. Address: 118-1 Toranomon 2-chome, Minato-ku, Tokyo (Tora no 1)
...Nawake Building) [Telephone 03 (502) 1476 (
(Representative)] 6. Subsistence of Amendment (1) The scope of claims is amended as shown in the attached sheet. (Delete the statement "(However, the total of these compounds is always 1c100 parts by weight)" in lines 5 to 4 of the 5th column below. However, the total of these compounds is always 100 parts by weight. The eyelids are deleted. (4) Description in lines 9 to 1o [(However, the total of these compounds is always 100 parts by weight.) (5) Correct the description in lines 712 to 13 of O9 to read “Tsuiya brush” and “T1 wire brush.” (6) Correct the following 9 to the 15th member's first robe. +21 1 (7) Undistributed copy of Figure 1 and Figure 2 attached drawings 9
I would like to make a correction, so I will reveal my sword I] brush. 2 Claims fla) 40-75i% by weight of silicon carbide as heat radiating material, b) 15-40% by weight of 3-20 parts by weight of silicon nitrogen, 5-20 parts by weight of phosphate, 2 parts by weight of chromium oxide. a heat radiation aid and a binder consisting of ~10 parts by weight, 2 to 2 parts by weight of tantalum carbide and 5 to 20 parts by weight of aluminum powder; A dense layer or coating film consisting of 3 to 15 parts of glass powder, 3 to 15 parts of acclimatized zirconium, 1 to 10 parts of silicon dioxide, 1 to 10 parts of magnesium oxide, and 1 to 10 parts of iron oxide. A thermally emissive ceramic coating composition comprising a bond enhancing additive and wherein the sum of components a), b) and C) is 100% by weight. (2) a) 40-75% silicon carbide as a heat radiating material; b) 15-40% silicon carbide, 3-20 parts by weight of silicon, 5-20 parts of phosphate, chromium oxide 2 to 10 weight parts, carbonized aluminum/tal 2 to 0 parts and a heat radiation aid and binder consisting of 5 to 20 weight parts of aluminum powder and C) 10 to 35 weight percent of aluminum oxide 1 to 10 parts by weight, 3 to 15 parts by weight of glass powder, 3 to 15 parts by weight of zirconium oxide, 1 to 10 parts by weight of silicon dioxide, 1 to 10 parts by weight of magnesium oxide, and 1 to 10 parts by weight of iron oxide. A thermally emissive ceramic coating composition comprising 100% by weight of components a), b) and 0) is applied to the substrate by VC coating, and the composition is VC-coated on the substrate.
Heat for 3 to 5 hours while increasing the temperature stepwise or continuously from the starting temperature of room temperature to a temperature of 400° to 5000°C, and further heat and bake at a temperature of 5500 to 800°C for 1 to 34 hours. A method of using the thermally emissive ceramic coating composition in a timely manner. (3) The method according to claim 2, wherein approximately 10 to 15 percent of water is added to the heat-emitting ceramic Al plate composition and the mixture is coated on the substrate. (4) The method according to claim 2 or 3, when the base material is a refractory material for the furnace inner wall or a metal structure in the furnace of a millet training furnace. Figure 1 Figure 2 Figure 3

Claims (4)

[Claims] (1) a) Thermal radiation of 40 to 75 weight units (1) and (7) silicon carbide, b) 15 to 40 weight units, silicon nitride 3 to 20 weight units, phosphate 5 to 20 weight units Modified from 2 to 10 M parts of chromium, 2 to 10 parts by weight of tantalum carbide, and 5 to 20 parts by weight of aluminum powder (although the total of these compounds is 0 to 100 parts by weight). Auxiliary materials and binders and C) 10 to 350 to 35 parts by weight, 1 to 10 parts by weight of aluminum, 3 to 15 parts by weight of glass powder, 3 to 15 parts by weight of zirconium oxide, 1 to 10 parts by weight of silicon dioxide, 1 to 10 parts by weight of magnesium oxide. It consists of 10 parts by weight of iron oxide and 1 to 10 parts by weight of iron oxide (however, the total amount of these compounds is always 100 parts by weight).It consists of additives that increase adhesion and coating strength and component a). , b) and C) have a total of 100 layers. (2) FL) Silicon carbide as a heat radiating material with a weight of 40 and -75, b) Silicon nitride with a weight of 15 to 40, 3 to 20, phosphate 5 to 20, oxidation Chromium type 2-10 can, 2-10 parts by weight of tantalum carbide and 5-20 parts by weight of aluminum powder (however, the total of these compounds is always 100 parts by weight); heat radiation aid and binder; and C. ) 10 to 35 parts by weight, 1 to 10 parts by weight of aluminum oxide, 5 to 15 parts by weight of glass powder, 5 to 15 parts by weight of zirconium oxide, 1 to 10 parts by weight of silicon dioxide, 1 to 10 parts by weight of magnesium oxide. (However, the total of these compounds is always 100 parts by weight) and 1 to 10 parts by weight of iron oxide.Consists of additives that increase adhesion and coating strength and component a. applying a thermally emissive ceramic coating composition on a substrate, in which the sum d-1 of a), b) and C) is an ioo weight factor;
From the starting temperature of room temperature, heat for 5 hours with increasing temperature stepwise or continuously at a temperature of 400"C to 500C, and then for 1 to 3 hours at a temperature of 550C to 800C.
A method of using the thermally emissive ceramic coating composition described above, comprising heating and baking for a time. . 3. The method of claim 2, wherein the thermally emissive ceramic coating composition is coated on the substrate with the addition of about 10 to 15 weight percent water. (4) The method according to claim 3, wherein the base material is an inner wall surface of an industrial heating furnace or a metal structure inside the furnace.