TWI687394B - Method for reduction firing ceramics by laser - Google Patents

Abstract

The present invention related to a method for reduction firing ceramics by laser. It features irradiating the blank body and glaze by laser. By the high energy density of laser, it can quickly reduction firing the blank body and glaze. Comparing to reduction firing by conventional kilning, the present method can saving fuel and time.

Description

Method for sintering ceramic by laser reduction

The invention relates to a method for sintering ceramics by laser reduction firing, and is a technical person who uses lasers to fire ceramics.

When making ceramics, it is mainly to make pottery blanks by drawing blanks, sharp blanks and drying blanks, and then apply glaze to the pottery blanks, and then kiln firing, so that the glaze melts and crystallizes into a smooth The glass-like outer layer covers the pottery billet. In addition to the basic waterproof effect, the glazes of different compositions will also show a variety of colors after kiln firing, which can achieve the decorative effect at the same time.

Ceramics can be divided into oxidizing firing and reducing firing during kiln firing. Oxidizing firing is literally shown. During firing, the kiln is kept in a state of sufficient oxygen, while reducing firing generally uses a gas kiln. To carry out, by controlling the air intake and exhaust during firing, the kiln is kept in an oxygen-deficient state. Therefore, the fuel in the kiln will obtain oxygen from the pottery and glaze, making the metal and alkaline earth family in the pottery and glaze. When the oxide raw materials are reduced, the reduction effect can be achieved, and due to the reduction burning in the kiln burning process, the raw materials will be reduced, and the color change will be completely different from the oxidation burning.

However, traditional kiln-based reduction firing has its shortcomings. For example, it often requires more than ten hours of kiln firing time, and it consumes a lot of fuel and is not environmentally friendly.

In view of the above shortcomings, the inventor believes that it is necessary to correct, so he has many years of experience in related technology and product design and manufacturing, upholds the excellent design concept, and researches and creates in view of the above disadvantages. The method of sintering ceramics by laser reduction firing of the present invention is introduced, which corrects the product structure to enhance the excellent effect of the product.

The main purpose of the method for sintering ceramics by laser reduction firing in the present invention is to provide a process method for achieving the effect of ceramic reduction firing by using laser.

In order to achieve the purpose of the previous disclosure, the method of sintering ceramics by laser reduction firing is to irradiate ceramic blanks or glazes with laser to achieve the sintering effect. With the high energy density characteristic of laser, the laser irradiation When the pottery blank or glaze is heated up rapidly, the effect of rapid sintering is achieved.

Compared with the conventional method of using traditional kiln firing, this method can be carried out in a general room temperature environment, and through the high energy density characteristics of laser, sintering can be completed more quickly, which greatly reduces the previous use of kiln The time and energy required for burning is a fairly progressive method.

The invention relates to a method for sintering ceramics by laser reduction, that is, using the laser generated by the laser device to sinter the ceramic blank or glaze, wherein the laser device is a carbon dioxide laser engraving machine sold on the market The wavelength of the CO2 laser is 10.6μm, the moving speed of the laser head (equivalent to the moving speed of the laser irradiation area) and the moving stroke can be set by the user, and it can also have a lifting platform to achieve three The function of the shaft travel, and the laser engraving machine used in the present invention has a focal length of the laser irradiation area diameter of 0.2mm, and can output a maximum power of 100W, the power density can be divided by the current power divided by the irradiation area radius Is obtained by squaring the square, and the maximum moving speed of the laser head is 1000 mm/sec.

1- Laser sintering test of ceramic raw materials:

In order to observe the effect of laser sintering on ceramic slabs and glazes, we first conducted laser sintering experiments on ceramics slabs and glazes with different proportions of ingredients. The results of several of these tests are shown below.

1.1-Laser sintering test of ceramic slab:

1.1.1-Miaoli soil [please refer to the first picture]:

In the laser sintering experiment of Miaoli soil, the composition of Miaoli soil is shown in the table below, the laser power is set to 20W, the laser movement rate is set to 1mm/sec, and the interval between two adjacent laser sintering paths Set to 0.5mm, the test results are shown in the first figure, Miaoli soil crystallized from the original brown to dark green glass. In addition, in the following table format, X ₂ O represents alkali metal oxide, XO represents alkaline earth metal oxide, X ₂ O ₃ represents boron group element oxide, XO ₂ represents carbon group element oxide, X ₂ O ₅ represents Nitrogen oxides.

1.1.2-Mixed feldspar kaolin (the weight ratio of feldspar to kaolin is 10:3) [please refer to the second picture]:

In the laser sintering test of feldspar mixed kaolin, its composition is shown in the table below, the laser power is set to 20W, the laser beam spot moving rate is set to 1mm/sec, and the interval between two adjacent laser sintering paths Set to 0.5mm, the test results are shown in the second figure.

1.2-Sintering test of glaze:

1.2.1-Transparent glaze [please refer to the third figure]:

The weight ratio of raw materials in the transparent glaze here is feldspar: calcium carbonate: kaolin: silicon oxide = 50: 10: 10: 30, the more detailed raw material ratio is shown in the table below, the laser power is set to 20W, laser light The point movement rate is set to 1 mm/sec, and the test results are shown in the third figure.

1.2.2-Feldspar glaze [please refer to the fourth picture]:

Keto feldspar with a composition of 100%, the laser power is set to 20W, the laser spot movement rate is set to 1~25mm/sec, the test results are shown in the fourth-a and four-b diagrams, especially the fourth-b It can be clearly seen in the figure that feldspar glaze has obvious glass characteristics of crystallization after laser sintering.

1.2.3-Glaze containing iron oxide (Fe ₂ O ₃ ) [please refer to the fifth picture]:

The glaze here is composed of a super-grade Keto feldspar: extra-white kaolinite: iron oxide = 70:30:2 weight ratio, followed by laser reduction, the test results are shown in the fifth figure, you can see Unearthed red glaze will be converted to green by laser.

According to the above test results, it can be seen that the use of laser to sinter the ceramics and glaze does have a crystallization effect and can replace the traditional kiln firing, and then it can directly spend less time in the room temperature environment to achieve the reduction firing effect. Moreover, the operator can freely adjust various laser parameters such as laser power and light spot moving rate, so as to achieve good sintering effect on ceramic materials with different characteristics.

1.3-Laser sintering test with traditional kiln-fired ceramic raw materials:

In addition to the above simple sintering of ceramics and glazes by laser, traditional kiln firing can be used first, and then laser can be used for secondary sintering, or laser sintering can be performed before traditional kiln firing. Test results As shown below.

1.3.1-Miaoli soil laser matching traditional kiln burning test [please refer to the sixth and seventh figures]:

The laser matching of Miaoli soil is divided into two types with the traditional kiln burning test. The first is to burn the Miaoli soil in the previous 1.1.1 at 800 ℃ in the electric kiln (the glaze is not glazed) Kiln firing is also known as sintering. The effect of sintering is to increase the water absorption of the ceramic slab to facilitate subsequent glazing), and then use the power of 20W and the moving speed of 1-20mm/sec to perform laser sintering. The test results are as follows The sixth-a and six-b diagrams show that the green glass transition blocks from the upper left to the lower right in the sixth-a diagram are the results of laser sintering at a rate of 1-20 mm/sec, respectively. After being kiln-fired and showing red earth color, and then performing second sintering at different rates of laser, Miaoli soil will appear in different shades of dark green because the iron oxides contained are reduced;

The second method is to first sinter the Miaoli soil in 1.1.1 by laser sintering, and then oxidize and burn it at 800 ℃ in an electric kiln. The test results are shown in the seventh figure. It will appear reddish brown.

1.3.2-Laser glaze with copper carbonate (CuCO ₃ ) glaze matched with traditional kiln firing test [please refer to figure 8]:

Here the glaze is made by mixing the weight ratio of extra-grade kettle feldspar: extra white kaolinite: copper carbonate = 70:30:3, followed by oxidizing and firing in an electric kiln at 1240°C and then secondary firing with laser. The test results are shown in the eighth-a and eight-b graphs. It can be seen that the oxidized green glaze will be reduced to copper red by the laser.

In the method of combining traditional kiln firing with laser in 1.3, the kiln firing temperature can be selected up to 1300 ℃, and can be taken to 100 ℃ per hour to raise the temperature to the selected maximum temperature, and then let The temperature in the kiln naturally drops.

In addition, in the several test processes listed in 1, it is found that when the laser power is set to more than 20W and the laser movement rate is set to less than 30mm/sec, the reduction effect is more obvious, and the test samples are located in the laser during the test. The focal length of the laser head makes the diameter of the laser spot on the sample 0.2mm, and it can be estimated that the reduction effect is better when the laser power density is (20W)/(0.01cm) ² = 200000W/cm ² or more.

2-Sintering method of ceramic greenware and glaze:

After confirming the sintering effect of the laser on the raw materials of the ceramic and glaze, the laser can be actually used to sinter the ceramic and glaze.

2.1-Sintering of the ceramic slab [please refer to the ninth to eleventh figures]:

In order to sinter the three-dimensional ceramic slab, the ceramic slab raw material is first made into a ceramic slab with a predetermined thickness, and then the ceramic slabs are stacked from bottom to top, and laser sintering is used before stacking the upper ceramic slabs. The predetermined block of the lower layer ceramic green sheet, and when the upper layer green ceramic sheet is sintered, the sintered block is connected with the sintered block of the lower ceramic blank sheet, so that the sintered block of each ceramic green sheet can be moved from the bottom to the bottom After the sintering is completed, the unsintered block is washed with water after standing and cooling, so that only a three-dimensional ceramic slab is left. As shown in the ninth figure, the ceramic slabs are stacked in sequence and used. Sintering, the tenth figure shows that the sintered block is ring-shaped, and the sintered block has obvious vitrification characteristics, and the eleventh figure shows that only one ring is left after removing the unsintered block Terra cotta.

[Please refer to the ninth to eleventh figures] In the method of laser sintering the three-dimensional pottery blank in the previous stage, although the upper-layer ceramic blank is placed on the lower-layer ceramic blank, the upper-layer cutout will cover the lower-layer ceramic The sintering block of the green chip, but because the laser engraving machine can freely set the three-axis movement stroke of the laser head, the sintering block of the upper ceramic chip and the sintering block of the lower layer can still be controlled to adhere Three-dimensional ceramic sinter is sintered upwards. In addition, although the eleventh figure shows that the sintered ceramic slab is a simple ring shape, it can also sinter a bowl with a bottom surface through the three-axis stroke setting function of the laser engraving machine. , Bottle-shaped or urn-shaped pottery blanks to meet actual needs.

2.2—Sintering of glaze:

When sintering the glaze, the laser is used to sinter the glaze directly. According to the aforementioned 1.2 and 1.3 tests, there are several ways to sinter the glaze:

a－Similar to the traditional kiln firing of the prepared raw glaze on the raw ceramics, but when the laser is used, the raw glaze is applied on the sintered cooked pottery, and then the laser is used. The glaze is sintered, and when the glaze is applied, the ceramic slab can be completely or only partially glazed. Similarly, when laser sintering is performed, the glaze can be completely or only partially sintered.

b-After the laser sintering in the previous section a mode, the traditional kiln firing is carried out.

c- After the sintering of the green pottery and the raw glaze applied on the raw pottery by the traditional kiln firing method, the laser is used to perform secondary sintering of the local area of the glaze, especially for the traditional kiln Burning is by oxidizing burning method, and then laser can be used to achieve local reduction burning effect, and the whole glaze shows multi-level color changes.

In the glaze sintering method of 2.2, the kiln firing conditions are based on 1.3, and the highest kiln firing temperature that can be selected is 1300°C, and the temperature can be increased to the selected highest temperature by 100°C per hour. Let the kiln naturally cool down, and the cooked pottery blank used in the method of 2.2 can be completed by the method of 2.1.

The method of the present invention for sintering ceramics by laser reduction has the following advantages:

1. Can greatly reduce the time and fuel cost required for sintered ceramics.

2. The local reduction burning effect can be achieved on the glaze, which cannot be achieved by relying only on traditional kiln firing.

The above is only one of the preferred embodiments of the present invention, and it should not be used to limit the scope of the present invention. That is to say, all equal changes and modifications made according to the scope of the patent application should still fall within the scope of this creative patent.

In summary, when the invention is known to be novel and progressive, and the invention has not been seen in any publication, it must comply with the provisions of Article 22 of the Patent Law.

no

The first figure is an example diagram of laser sintering Miaoli soil in the method of laser reduction and sintering ceramics of the present invention. The second figure is an example diagram of laser sintering feldspar mixed kaolin in the method of laser reduction and sintering ceramics of the present invention. The third figure is an example diagram of laser sintering transparent glaze in the method of laser reduction and sintering ceramics of the present invention. The fourth-a diagram is an example diagram of sintering feldspar glaze by laser in the method of sintering ceramics by laser reduction firing of the present invention. The fourth-b picture is a close-up example diagram of laser sintering the feldspar glaze in the method of laser reduction and sintering ceramics of the present invention. The fifth figure is an example diagram of laser reduction firing of glaze containing iron oxide in the method of sintering ceramics by laser reduction firing in the present invention. The sixth-a diagram is an example diagram of the method of the present invention for firing and sintering ceramics by laser reduction and firing the Miaoli soil in a traditional kiln and then firing it by laser for the second time. Figure 6-b is a close-up example diagram of the method for laser-reducing and sintering sintered ceramics of the present invention by firing Miaoli soil in a traditional kiln and then firing it with laser for secondary firing. The seventh figure is an example diagram of the method for sintering ceramics by laser reduction sintering of the present invention, followed by laser sintering of Miaoli soil and then traditional kiln firing. The eighth-a diagram is an example diagram of the method for sintering ceramics by laser reduction firing in the present invention, after the glaze containing copper carbonate is firstly fired in a traditional kiln and then secondarily fired by laser. The eighth-b picture is a close-up example diagram of the sintering of ceramics by laser reduction firing in the present invention, after the glaze containing copper carbonate is firstly fired in a traditional kiln and then secondarily fired by laser. The ninth figure is an example diagram of stacking ceramic green sheets and performing laser sintering when sintering ceramic slabs in the method of laser reduction sintering ceramics of the present invention. The tenth figure is an example diagram of the sintering block of the ceramic green sheet when sintering the ceramic green in the method of laser reduction firing sintered ceramic of the present invention. The eleventh figure is an example diagram of the ceramic sintered by the method of laser reduction sintering ceramics of the present invention.

no

Claims (6)

A method for sintering ceramics by laser reduction firing, characterized in that: using a laser produced by a laser device to sinter the ceramic greenware, the steps are as follows: the ceramic raw material is first made into ceramic greenware pieces, and then each ceramic block The green sheets are stacked from bottom to top, and before stacking the upper ceramic sheets, the predetermined blocks of the lower ceramic sheets are sintered by laser, and when the upper ceramic sheets are sintered, the sintered blocks and the lower ceramic sheets are The sintered blocks are connected, so that the sintered blocks of each ceramic green sheet are integrally bonded from bottom to top. After the sintering is completed, the unsintered blocks are removed after standing and cooling, leaving a three-dimensional ceramic blank. A method for sintering ceramics by laser reduction firing, which is characterized by using a laser produced by a laser device to sinter the glaze, first applying the raw glaze to the sintered cooked pottery blank, and then using the laser Sinter the glaze, and when applying the glaze, you can choose to glaze the ceramic blank completely or only in local areas. Similarly, when performing laser sintering, you can also choose to sinter the glaze completely or only in local areas. After that, the traditional kiln is burned. A method of sintering ceramics by laser reduction firing, which is characterized in that the green pottery and the raw glaze applied on the green pottery are sintered by oxidizing in a traditional kiln firing method, and then the laser is used Those who come to perform secondary sintering of glaze locally. As described in item 2 or 3 of the patent application scope, a method of sintering ceramics by laser reduction firing, wherein the power density of the laser is 200,000 W/cm ² or more, and the moving speed of the laser irradiation area is 30 mm/sec or less. As described in item 2 or 3 of the scope of the patent application, the method of sintering ceramics by laser reduction firing, in which the highest kiln firing temperature is 1300 ℃. The method of sintering ceramics by laser reduction firing as described in item 2 or 3 of the patent application scope, in which the temperature is raised at 100°C per hour during kiln firing.

Images