JPS6127866B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a glaze heater in which a heating element is formed on a substrate such as glass or porcelain using printing technology, and then fired. Traditionally, nichrome wires and strips have been used for heating in space heaters and electric heaters, etc., and when special high temperatures or durability are required, Kanthal is used as a heat source material. and used. Conventionally, these nichrome materials have been used in heaters related to space heaters, electric heaters, and
It is used in a variety of products such as irons and rice cookers. Various methods have been devised to use it, and costs have been thoroughly reduced. However, in heaters and the like that use nichrome material as a heat source, (1) it is difficult to obtain a heat source that operates in a relatively medium temperature range, for example around 600°C; (2) When using nichrome material as a heat source, the wavelength of the radiant heat emitted from the heat source is mostly 1 micron or less. This means that the wavelengths at which humans receive radiant heat and feel comfortable and warm are 5 to 6.
Compared to the size of a micron, the wavelength is quite short, and there are drawbacks such as the fact that you can actually feel pain in the warmth and feel uncomfortable, and (3) you cannot obtain a heat source of any shape. . It is an object of the present invention to provide a glaze heater which eliminates the drawbacks of the conventional technology, allows a heat source in a medium temperature range to be easily obtained, and allows a heat source of any shape to be constructed using printing technology. The invention will now be described. The conductive fine powder is made of _MoSi2 , which is a compound of Mo and Si.
Mg ₂ Si, which is a compound of Mg and Si, or silicides from its groups, especially ZrSi ₂ , NbSi ₂ ,
TaSi ₂ , CrSi ₂ , WSi ₂ , MnSi ₂ , FeSi ₂ , CoSi ₂ ,
It consists of a mixture containing one or more of CoSi, Co ₂ Si, NiSi, Ni ₂ Si, Ni ₃ Si ₂ , etc. A mixture of these silicides may be mixed after forming each silicide, but
Mix Mo, Mg, Ta, Si, etc. in the required ratio,
Either as a powder or after forming it into a block, heat it at 1200℃ to 1400℃ in vacuum or inert gas.
A mixture of silicides may be simultaneously synthesized by heating to 0.degree. C. (this temperature varies somewhat depending on the composition ratio constituting the conductive powder). The results of the study showed that the material obtained by the latter method had better heat resistance properties. The mixture thus synthesized is pulverized using a pulverizer to form a fine powder of approximately 1 micron. When a glaze paste is printed on a substrate and fired, if the thermal expansion differs from that of the substrate, the glaze layer will peel off, so it is necessary to match the thermal expansion of the glaze layer to that of the substrate. What characterizes this is the glass frit in the glaze paste. For example, when alumina is used as a substrate, the glass frit is made by adding B ₂ O ₃ , SiO ₂ , and BaO to the materials. In addition, MgO, Al ₂ O ₃ , etc. are added to improve moisture resistance. Also,
Similar results can be obtained by adding ZnO in addition to BaO. If a substrate with a small coefficient of thermal expansion, such as crystallized glass or quartz, is printed and fired, cracks will occur in the glaze layer due to the difference in thermal expansion when the glass frit is used. Therefore, the glass frit for the glaze must also have a relatively small coefficient of thermal expansion. For example B ₂ O ₃
-It is a SiO ₂ -based glass with a relatively large amount of SiO ₂ . This inevitably increases the glazing temperature. Glass having such a composition is made and then crushed into a fine powder of 2 to 3 microns in size using a pulverizer. The conductive fine powder and glass fine powder obtained in this way are mixed in an appropriate ratio, and in order to provide printing properties, an organic caking agent is prepared by mixing turpentine oil and ethyl cellulose in a ratio of 9:1 (weight ratio). Add the ingredients to make a paste. this paste
A 200-mesh screen mesh is used to print on the substrate, dried at a temperature of about 120°C, and then fired in air or in an inert gas at a temperature that turns the glass frit into a glaze. A heater layer is formed on the surface. The electrodes were made by screen printing Ag-Pd glaze paste before forming the heater layer, drying it and then firing it.
A Pd electrode was used. There is no particular problem with electrodes made of gold, platinum, silver, etc. instead of Ag-Pb electrodes. Examples will be described below. Example Mo, Ta, and Si powders were mixed as MoSi ₂ and TaSi ₂ at a weight ratio of 80:20, formed into a block shape, and then heated at a temperature of 1400°C.
A conductive material made of a mixture of MoSi ₂ and TaSi ₂ was fabricated by processing in vacuum for an hour. This was pulverized using a pulverizer to obtain a fine powder of about 1 micron. Next, (H ₃ BO ₃ ) 51.3% by weight, (BaCO ₃ ) 34.2% by weight, (SiO ₂ ) 3.4%, (CaCO ₃ ) 2.55% by weight,
(MgO) 2.55% by weight was mixed, placed in an alumina crucible, and melted at 1200°C, then poured into water, coarsely pulverized, and then pulverized into a fine powder of 2 to 3 microns using a pulverizer. The conductive fine powder thus prepared and glass frit were mixed at a weight ratio of 20:80. Next, 0.4 cc of the organic binder was mixed with 1 g of this mixture to form a paste. This paste was printed in an arbitrary pattern on an alumina substrate using a 200-mesh screen mesh. Next, after drying this, the maximum temperature
It was fired in a tunnel furnace heated to 850℃ and made into a glaze heater. The thickness of the resulting heater layer was 15 microns, and its sheet resistance was 50Ω. On the electrode
An Ag-Pd electrode was used. In this way, a load is applied to the created glaze heater, and the surface temperature reaches 600℃.
A continuous load life test was conducted. As a result, the resistance value change of the heater was about 2% over 1000 hours. At this time, the wavelength of the radiant wave of the heater is as shown in the figure, and the radiant energy is 3~
It had a first peak at a wavelength of 4 microns and a second peak at 6 to 8 microns, and was warm enough to cause no pain. Example 2 Mo, Ta, Mg, Si = MoSi ₂ , TaSi ₂ , Mg ₂ Si=
After mixing at a ratio of 60:20:20 (weight ratio) and forming into a block, the mixture was mixed in the same manner as in Example 1.
A conductive material made of a mixture of MoSi ₂ , TaSi ₂ , and Mg ₂ Si was produced by heat treatment at 1200°C. In the same manner as in Example 1, it was made into a paste, printed, and fired in a tunnel furnace at 850°C to obtain a glaze heater. The sheet resistance value was 80Ω. A life test was performed by applying a load between the electrodes so that the surface temperature of the heater reached 400°C, and the resistance value change was 0.5% after 1000 hours. In addition, when the temperature was set to 650°C, it was about 2%. The radiation wave at this time was almost the same as in the example and had a first peak of 3 to 4 microns. Example 3 The conductive fine powder prepared in Example 2 was
_B2O3 : _SiO2 : _{Al2O3 :} BaO: _MgO : _Na2O =9.8:
Mix glass frits in the ratio of 81.6:3.4:3.1:1.0:1.1 (weight ratio) at 20:80 (weight ratio),
This was mixed with an organic binder to form a paste. Printing was performed using LiO-Al ₂ O ₃ -SiO ₂ -based crystallized glass as a substrate in the same manner as in Example 1, and dried at 120°C. Next, it was glazed at a temperature of 1000°C in Ar gas and used as a heater. As a result of investigating the same characteristics as in Example 1, the area resistance value was 120Ω, and the resistance was 2% after 1000 hours under a load of 700℃.
showed the change in resistance value. Furthermore, the radiated waves were approximately the same as in Example 1. Example 4 MoSi ₂ , Mg ₂ Si and
CrSi ₂ , FeSi ₂ , MnSi ₂ , TiSi ₂ , ZrSi ₂ , NbSi ₂ ,
WSi ₂ , CoSi, CoSi ₂ , Co ₂ Si, Ni ₂ Si, Ni ₃ Si ₂ ,
A mixture containing one of NiSi was prepared in the same manner as in Example 1, and made into fine powder using a pulverizer. This was mixed with the same glass frit as in Example 1 at a weight ratio of 80 to form a paste. This was printed on an alumina substrate and fired in air at 850°C to create a glaze heater. The results of investigating the same characteristics as in Example 1 were as shown in the following table. Note that the first peak value of the radiation wave was approximately the same as in Example 1.

【table】

[Table] Based on the above configuration, the present invention produces the following effects. (1) Printing technology allows it to be formed into any shape, making it easy to obtain complex structures. (2) As shown in Figure 1, the wavelength of the radiation waves from the heat source is a long wavelength with a peak of 3 to 4 microns, making it an excellent heat source for heating. (3) The material used is generally silicide, which has excellent heat resistance. Among them, molybdenum silicide is used as a heat source in electric furnaces at temperatures of several hundred degrees, and is an extremely heat-resistant material, so it can essentially be used as a heat source from low to high temperatures.

[Brief explanation of the drawing]

The figure shows the wavelength intensity distribution of the heat source. No explanation of the sign.

Claims (1)

[Claims] 1. A glaze made by applying and baking a paste on a substrate, which is a mixture of molybdenum silicide or molybdenum silicide with one or more of the silicides from the group and from the group to the group, heat-treated and pulverized conductive fine powder, and glass frit. heater.