JPS6395179A - Method of glazing cement product - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for glazing cement products by plasma spraying. In particular, the present invention is useful as a method for producing glazed cement products that do not cause thermal deterioration of the base material.

[Conventional technology and its problems]

Conventionally, cementitious base material 1 such as concrete board, GRC
Board 1 Glazed cement products having weather resistance and aesthetic appearance are known, in which a glaze is applied on an asbestos cement board or a calcium silicate board. In general, the production of such glazed cement products involves kneading a raw material composition of cement, water and aggregate, as well as various additives and reinforcing fibers added thereto, and then pressurizing, extruding, or molding the mixture. Molded using a molding method such as pouring.

It is manufactured by applying a glaze to the obtained molded body, firing it, and then subjecting it to rehydration treatment. This method not only requires a large amount of energy to fire the entire cement product, but also has problems in that temperature control and rolls are difficult to separate during firing. There was also the problem that large cement products such as prestressed concrete and reeet boards could not be glazed due to the size limitations of the kilns used. Furthermore, the deterioration of the cementitious base material caused by calcination is recovered by rehydration.

Currently, it cannot be used for cementitious base materials containing fiber materials that are subject to severe thermal deterioration, such as GBC boards containing glass fibers and asbestos cement boards containing asbestos.

In order to solve these problems, as a method to form a glass layer on a cementitious base material that is sensitive to heat, for example, and deteriorates due to heat at temperatures above about 500°C, However, attempts are made to obtain a glass layer by melting the surface of the base material itself or by melting the glass raw material applied to the surface of the base material; Attempts have been made to melt the glaze particles forming the glaze and apply them directly to the substrate. In connection with this, the applicant first applied a glaze slurry on a cementitious base material in a wet manner, moved the base material and/or a plasma generator relatively, and removed only the glaze coating film using a plasma flame. We proposed a method of melting and adhering the glass layer to the cementitious base material.

However, in the case (2) above, the flame was unstable and it was difficult to control the flame condition, and it was difficult to obtain a glass layer that was uniform in thickness and color.

Therefore, since the glaze melts unevenly, peeling between the glass layer and the base material is likely to occur. You can also adjust the color of the glass layer.
This is shocking because the soot adhesion caused by the flame and the oxidation conditions within the flame change the color of the glass layer.

Furthermore, the surface of the base material also undergoes thermal deterioration due to heat transfer.

In the case of (2), the glaze particles were incompletely melted in the flame or blocking of the particles occurred, so that a uniform glass layer could not be obtained. Further, since the area of the flame is large, the spraying time is long, and there are problems of peeling and thermal deterioration due to deterioration of the base material and partial melting. Furthermore, there is a risk that the glaze particles will not be stably dissolved, resulting in a film-like substance.

Although method (2) provides a glass layer with excellent adhesion, it requires two steps: wet glazing and subsequent plasma flame melting, and there is a possibility that bubbles, pinholes, etc. may occur, albeit slightly. Therefore, there is a process that can completely glaze in one step.
So desirable.

On the other hand, there has been talk of a technique for improving the durability of metal materials by plasma spraying ceramic powder onto metal substrates. In the case of a material whose surface is easily deformed, such as metal, it is possible to weld ceramic particles while causing physical deformation of the substrate. However, in the case of a heat-degradable substrate such as a cementitious base material whose surface is difficult to deform, it is necessary to weld the ceramic particles by deformation alone, which has been impossible due to poor adhesion. The melting point of the ceramic itself is high, and even if it is completely melted, crystals tend to precipitate from the melt, making the film porous, so it is difficult to obtain a glossy film surface on the base material even in the case of a metal plate. It was difficult. In connection with the above, the present applicant has proposed a method for producing glazed cement products in which a glaze is welded by gas flame spraying or the like to a cementitious base material that has been previously calcined to a temperature of 500° C. or higher. With the flame irradiation technology at this point, when welding a glaze onto a base material, it is intended to irradiate and melt the base material in addition to thermal spraying, so at least the surface of the cementitious base material is heated to 500°C or higher. Steam and decomposition gases are released from the material onto the glazed surface.

Therefore, it has been necessary to previously calcinate the cementitious base material to a temperature of 500° C. or higher, and then rehydrate it with saturated steam or the like after glazing.

[Means for solving problems]

The inventors believe that temperatures above about 10,000°C and typically 15#
Glassy powder with a predetermined particle size range is introduced into the plasma flame of a plasma gun having a center flame temperature of OOO~20,000℃, and is quickly and sufficiently dissolved to make the particle size as uniform as possible. The above-mentioned problems were solved by colliding the vitreous melted particles onto the cementitious base material using the blasting force of the plasma flame while maintaining a predetermined spraying distance and scanning speed.

That is, according to the present invention, vitreous powder having an average particle size of 1 to 400 microns is introduced into the high-temperature plasma flame of the Gutsuzu i thermal spraying apparatus, and the vitreous solubilized particles are sufficiently melted to form a hydrated cementitious base material and/or Alternatively, a method for glazing a hydrated cementitious base material and a glazed cement characterized by performing plasma spraying by colliding the plasma flame onto the cementitious base material while moving the plasma spraying device relatively. A method of manufacturing the product is provided.

The glazing method of the present invention removes defects such as air bubbles, pinholes, and poor fusion areas contained in the glaze layer of cement products that have been glazed using conventional glazing methods. A method of obtaining a homogeneous and defect-free glaze by thermal spraying can also be advantageously applied.

[Detailed description of the invention]

The cementitious base material in the present invention includes a hydraulic inorganic cement material as an essential component, and aggregate, reinforcing material,
It means a base material made of a molded article that may optionally contain additives and the like. The base material is typically.

Although it has a substantially planar surface to be glazed, the surface may be curved. A typical example of the above inorganic cement material is Portland cement.

Al? cement, blast furnace cement, jet cement,
Examples include slag cement, gypsum cement, and mixtures thereof. Normally, ordinary Portland cement is used. Examples of typical cementitious base materials to which the method of the present invention can be applied include:

= concrete material, spancrete, foamed concrete) (
ALC, etc.) material, silica board, slate board, glass fiber reinforced concrete (GRC), carbon fiber reinforced concrete 17-
) (CFRC) and other plate-shaped and rod-shaped objects. In addition to being flat, the shape may be curved to the extent that one jet thermal spraying is possible.

The average particle size range of the glassy powder described above depends on its meltability, but is generally about 1 to about 400 microns in diameter, preferably about 4 to about 250 microns, and most preferably about 10 to about 250 microns in diameter.
It is about 150 pochrons. Note that when the average diameter of the glassy powder is less than 1 micron, it scatters before reaching the substrate. Alternatively, the glass powder rapidly melts near the supply port and causes blocking. If it exceeds 400 ζ chrome, it becomes difficult to uniformly supply the glass powder. Even if it is possible to supply it.

Melting in the plasma flame is insufficient. The vitreous powder is usually one obtained by melting a glaze, vitrifying it, and pulverizing it, but it may also be a powder of other ordinary glass.

The power of the plasma and the distance between the plasma spray gun and the cementitious substrate are such that the substrate surface is maintained at a temperature of less than about 450°C by the plasma spray (e.g., about 400°C, preferably about 300°C). The temperature is set so that it does not reach temperatures as high as ℃.

Therefore, the output of a plasma gun is usually about 1oKw to about 60Kw.
A range of Kw is appropriate. Also, the above distance is usually 1
The thickness is approximately 0 mm to 300 mm, and in the case of vacuum spraying, it is up to approximately 10 mm. A distance of about 20 mm or more is generally desirable to avoid thermal damage to the substrate and device. The irradiation area of the plasma flame on the base material is generally circular with a diameter of about 5 to 100 mm.

Plasma spraying is usually performed using a plasma gun or a cementitious base material at a constant scanning speed (usually several centimeters to tens of centimeters) in the left and right direction.
m/sec) at fixed scanning intervals (usually several mm to several cm, depending on the irradiation area of the plasma flame). The feed rate of the glass powder is adjusted so that a glass layer of tens to hundreds of microns can be obtained in one scan. The above scanning is usually performed once to obtain the desired thickness of the glass layer.

Of course, it is also possible to scan twice.

The plasma flame used in the present invention mainly refers to a high-temperature, high-speed plasma jet formed by ionizing an inert gas such as nitrogen gas, argon gas, neon gas, or the like. Furthermore, hydrogen, air, etc. may be used in addition to the inert gas, if necessary.

Although the method of the present invention is advantageously applied to cementitious substrates which normally have a substantially planar surface to be glazed, it can also be applied advantageously to cementitious substrates which have a surface to be glazed that is substantially planar, but which has a curved surface that does not undergo sudden changes in shape. can also be applied. That is, in the latter case, as long as the change in distance between the surface to be glazed and the plasma spraying device (e.g. plasma spraying device) is less than about 1096, more precisely less than about 2X, it can be carried out in the same way as in the case of a flat surface. .

If the distance between the two changes by about 10X or more, more precisely about 2% or more, the position of the plasma gun should be adjusted according to the change in the curved surface so that the distance to the curved surface to be glazed remains almost constant. It is desirable to move the plasma spray flame in the direction of the spacing and apply the plasma spray flame. In addition, when trap-glazing the surface of a rod-shaped base material such as a cylinder or a cylinder, the plasma flame can be applied, for example, by rotating and relatively moving the rod-shaped base material to be glazed.

The apparatus used according to the invention essentially consists of at least one plasma gun and a support which respectively holds the plasma gun and, if necessary, the substrate to be glazed. Furthermore, means are provided for moving the gun support and/or the substrate support in order to uniformly apply the plasma spray flame over the entire surface to be glazed. For example, a plurality of plasmins are arranged and fixed at predetermined intervals, and a conveyor is used to move the substrate to be glazed while maintaining a fixed distance from the guns in a direction substantially perpendicular to the arrangement of the guns. An example of a device having this configuration is illustrated.

An embodiment is also exemplified in which one piece of plasmin is moved back and forth in a direction perpendicular to the transport method in place of the plurality of guns.

Furthermore, in the case of the base material having the above-mentioned curved surface, the position of the plasma gun can be changed in the direction of the distance between the two in accordance with the change in the curved surface. Note that each moving means in each of the above embodiments can be automatically controlled by electronics. These control means include, for example.

This can be achieved based on technical common sense regarding automatic machine tools, etc.

〔Example〕

The method of the present invention will be explained more specifically by the following examples.

Example 1 Glass powder having the composition (parts by weight) shown in Table 1 below was mixed with 37 to 88
Prepared to micron particle size range. This glass powder 4,
As shown in Figure 1, FT-A manufactured by Plasma Technique Co., Ltd.
200 ([1) was sent into the plasma flame 6 of the Plas i thermal spray gun 5 and sprayed on the asbestos-reinforced concrete plate 2 under the conditions shown in Table 2 below. 100 kron) 3
A glazed concrete board 1 having the following properties was obtained. No damage was observed in the obtained glazed concrete board 1, and no deterioration in the strength of the concrete substrate occurred. The adhesion strength between the coating and the concrete plate is approximately 60 kgf.
It was 7cm2.

Table-1 8i02 69 Na2O1 At203 14 Kto 1Li20
9 B201 6 Table-2 Plasma output crab 650AXd6V (42,9KW) Distance (d): 90mm Plasma gun scanning interval (width): 4mmExample 2 Glass powder with the same composition as Example 1 with a particle size of 37-88 microns Adjusted to within the range. This glass powder was thermally sprayed onto a concrete substrate using the same equipment as in Example 1 under the conditions shown in Table 3 below. As a result, a glazed concrete board with a glossy glass coated surface (thickness of approximately 100 mm) was obtained. No damage was observed to the glazed concrete board, and no deterioration in the strength of the concrete substrate occurred. The adhesion strength between the coating surface and the substrate is approximately 50 kg f/c
m2 is b.

Table-3 Plasma output crab 560 AX68V (3 & IKW) Distance (d) Near 0rnm Plasma gun scanning speed: 22Cm/sec Scan interval (width)
:4mm Example 3 (Comparative Example) Ceramic powder (mullite powder) having the composition (parts by weight) shown in Table 4 below was thermally sprayed onto a concrete substrate using the apparatus of Example 1 under the conditions shown in Table 1-5.

As a result, a shiny surface could not be obtained. Furthermore, the adhesion strength of the membrane surface to the concrete is approximately 10 kg f/
cm! It was a weak one.

Table-4 At, 0. To 766 St 22.4 Na! 0 α3 Fe! 03 α2 Other α5 Table-5 Fu5 Sma-de-kani 500AX 62V (31 to 11
) Distance (d): 12omm Plasma gun scanning speed: 16cm/sec Scan interval (
@): 4mm [Function and Effect] When glass powder with a particle size within a predetermined range is introduced into a plasma flame, the glass powder melts quickly and completely in the plasma flame at a high temperature of 15,000 to 20,000°C. death.

Very low viscosity glass melt particles are formed.

By spraying this directly onto the cementitious base material at predetermined intervals using the ejection power of plasma flame and allowing it to cool, a glossy coating surface can be obtained without deteriorating the strength of the base material. .

Therefore, the method of the present invention has the following effects: (1) A glass layer that is glossy and firmly adheres to the substrate can be obtained.

■No strength deterioration occurs due to heating of the base material. Therefore, it is not necessary to restore the deteriorated strength of the cementitious base material by a rehydration process. ■Even if the base material surface is heated during a short scanning time by plasma spraying, the temperature is generally below 300°C, so the evaporation or decomposition components in the cementitious base material will gasify due to S radiation and damage the glaze surface. There isn't. Therefore.

Since calcination before thermal spraying is not required, it can be advantageously applied to large-sized products. (2) Since the glazing according to the present invention is a dry glazing that does not use water, bubbles, pinholes, etc. in the glaze layer are avoided as in the conventional method.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the method of the present invention. 1...Glazed concrete board

Claims (1)

[Claims] (1) While relatively moving the plasma spraying equipment and/or the hydrated cementitious base material, it is sufficient to introduce vitreous powder with an average particle size of 1 to 400 microns into the high temperature plasma flame of the plasma spraying equipment. A cement, characterized in that plasma spraying is performed by impinging vitreous molten grains onto the hydrated cementitious base material by the jetting force of the plasma flame without substantially thermally deteriorating the base material. How to glaze the product.