JPH072546A - Production of fluorphlogopite glass ceramics - Google Patents

Abstract

PURPOSE:To produce inexpensive fluorphlogopite ceramics having high machinability by effectively utilizing waste stones of KOKA-SEKI (a kind of pumice) produced in NI Island of the IZU Islands, etc., as a main raw material. CONSTITUTION:These fluorphlogopite ceramics are obtained by blending 100 pts.wt. KOKA-SEKI with 10-30 pts.wt. MgO component, 5-15 pts.wt. K2O component. 3-10 pts.wt. F component, 2-10 pts.wt. B2O3 component and 0-2 pts.wt. Na2O component, melting the resultant blend, heat-treating the prepared glass and crystallizing the glass.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for effectively producing fluorphlogopite glass-ceramics, which is inexpensive and has high machinability, by making effective use of scraps of anti-firestone produced in Niijima, etc. of the Izu Islands.

2. Description of the Related Art Up to now, machinable fluorine phlogopite glass-ceramics have been expensive and have high quality silica sand (SiO 2).
₂ ), aluminum hydroxide (Al (OH) ₃ ), magnesia (MgO), magnesium fluoride (MgF ₂ ), potassium carbonate (K ₂ CO ₃ ), boric acid (H ₃ BO ₃ ) as raw materials at high temperature. It is produced by melting for a long time [see, for example, Japanese Patent Application No. 46-49864]. Therefore, it becomes an extremely expensive material, and it is unavoidable that a substitute must be used. Further, the conventional products are not sufficiently high in machinability, and the color is limited to white.

Conventionally, machinable glass ceramics used for machine parts and the like have high raw fuel costs because they are produced by melting expensive and high-quality artificial raw materials at high temperature for a long time. It has been difficult to inexpensively supply glass-ceramics with high workability. Anti-firestone is a porous volcanic glass with a huge reserve of 1 billion tons on the Niijima island of Izu Islands. It is used as a part of building materials and a small amount of small debris remains unused and discarded. In Niijima, production of special products using anti-fire stones is being promoted for industrial promotion, but materials suitable for special craft products that are easy to machine have not been produced so far. The present invention is
Effective use of anti-pyroclastic stones to save energy at low cost,
Moreover, it is an object to provide a method for producing a colored fluorophlogopite mica glass-ceramic having high machinability.

[Means for Solving the Problems] Unused anti-pyroclastic stone is used as a main raw material, and an inexpensive low-grade potassium carbonate (K
₂ CO ₃ ), magnesia (MgO), magnesium fluoride (MgF ₂ ), borax (Na ₂ B ₄ O ₇ ), and the like are used to produce an inexpensive and highly machinable colored fluorophlogopite glass ceramic. Since the main component of anti-fire stone is vitreous, its melting rate is much faster than that of silica sand, which is the main raw material of conventional glass, so fuel can be saved. In addition, the alumina material that is required in large quantities in conventional products is difficult to melt and glass defects such as striae are likely to occur, but by using anti-firestone containing a large amount of alumina as a raw material, it becomes easy to melt glass with few defects. You can Since Na ₂ O component lowers machinability, expensive boric acid is used as a raw material of B ₂ O ₃ component in the conventional product, but inexpensive borax can be used in the present invention. Fe ₂ O ₃ and S components are not always necessary, but the addition of these compounds improves the machinability, shows better machinability than conventional products, and is a yellow-brown to black-brown fluorophlogopite glass. Ceramics are obtained.

[Function] 1 mm under-anti-firestone powder 100 crushed and classified
g to potassium carbonate (K ₂ CO ₃ ) 10 to 20 g
(5-10 g as K ₂ O), magnesia (MgO) 5
To 20 g, magnesium fluoride _(MgF 2) 5 to 20
g, borax _{(Na 2} B 4 _{O 7,} as anhydrous) 5-10
g, iron oxide (Fe ₂ O ₃ ) 0 to 4, Glauber's salt (Na ₂ S)
When a batch containing 0 to 8 g of O ₄ (0 to 2 g as S) is melted at 1450 ° C. for 2 hours, a homogeneous glass is produced. When this glass is heat-treated at 1100 to 1200 ° C. for 1 to 8 hours, a brown crystallized glass in which crystals are uniformly deposited on the entire glass is obtained. This main crystal is fluorophlogopite (K
Mg ₃ AlSi ₃ O ₁₀ F ₂ ). Anti-fire stone powder 100
When the ratio of each auxiliary material to g is out of the above range, the crystal growth of fluorophlogopite is insufficient and the machinability is significantly reduced. The iron and sulfur components have the same machinability as conventional products even if they are not added, but the machinability is greatly improved by adding an appropriate amount, and it changes from yellowish brown to blackish brown. Iron sulfide can be used instead of iron oxide and Glauber's salt. In order to uniformly melt fluorophlogopite mica glass ceramics raw materials of the same chemical composition, it takes 4 hours or more at 1450 ° C. when general raw materials are used, but 1450 ° C. for 2 hours is sufficient if anti-firestone is the main raw material. . The heat treatment temperature is
Crystal growth is extremely slow below 1100 ° C.
At temperatures above ℃, high machinability cannot be obtained because the fluorophlogopite crystals remelt.

EXAMPLES Examples of the present invention in which 1 mm under-anti-firestone powder having the chemical composition shown in Table 1 is used as a main material are shown in Tables 2 and 3. Each blended raw material mixed for 1 hour in an automatic mortar was placed in a crucible, melted in an electric furnace, and the plate-shaped glass was heat-treated to produce brown fluorophlogopite glass ceramics.
Iron and sulfur were not added to the yellow-brown color, and the added ones were changed to black-brown color. Potassium carbonate for anti-firestones,
As for the mixing ratio of magnesia, magnesium fluoride and anhydrous borax, B in Table 2 was appropriate and the machinability was the best. Moreover, machinability was further improved by adding an appropriate amount of iron and sulfur. The machinability of the blended composition of B in Table 2 was examined by changing the heat treatment temperature and the heat treatment time.
Is. What was heat-treated at a temperature of 1130 to 1200 ° C. for 2 to 8 hours had relatively high machinability. It was necessary to heat-treat for a long time at a lower temperature, and high machinability was obtained for a short time at a higher temperature. Those with low machinability had small fluorphlogopite crystals, while those with the highest machinability had grown to a crystal size of 10 to 20 μm. The characteristic values of the fluorophlogopite glass-ceramics obtained in the present invention are shown in Table 4 in comparison with the conventional product. The machinability test was conducted with a carbide drill with a diameter of 5 mm at a rotation speed of 520 rpm at 7 k.
A hole was made in the sample for 1 minute while applying a load of g, and the depth thereof was measured with a caliper and expressed as a cutting speed (mm / min). The coefficient of thermal expansion is an average value from room temperature to 400 ° C. Shore hardness was measured with a Shore hardness tester.

INDUSTRIAL APPLICABILITY The present invention has an enormous reserve and enables the effective use of a large amount of dumped anti-pyroclastic rubble, and is lower in cost and more machinable than conventional products. It is effective in supplying glass ceramics to the market. 6 as a raw material for fluorophlogopite mica glass ceramics
0 wt. %, Anti-fire stones can be used, the auxiliary raw material may be of low grade, and the boric acid raw material can be replaced with borax, so that the raw material cost can be significantly reduced. Since anti-firestone is glassy, it has excellent meltability, and since the melting rate is more than twice that of general raw materials, it is effective in saving fuel. Invented product has better machinability than conventional product, cutting speed is 60%
Since it has also improved, it is effective in reducing the machining cost. By coloring in brown, it is effective to provide materials suitable for local specialty products.

Continued Front Page (72) Hidemi Koyama, 3-2-8 Sakuratsumi, Musashino City, Tokyo

Claims (1)

[Claims] "1" 100 parts by weight of anti-fire stone, MgO component 10 to 30, K
₂ O component 5 to 15, F component 3 to 10, B ₂ O ₃ component 2
10, Na ₂ O components 0 to 10, Fe ₂ O ₃ components 0 to 4,
A method for producing a fluorophlogopite glass-ceramic excellent in machinability, which comprises mixing 0 to 2 parts by weight of each of S components and heat-treating a glass obtained by melting.