KR101288958B1 - Manufacturing method of magnesia-based refractory article improved corrosion resistance and magnesia-based refractory article manufactured thereby - Google Patents

Manufacturing method of magnesia-based refractory article improved corrosion resistance and magnesia-based refractory article manufactured thereby Download PDF

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KR101288958B1
KR101288958B1 KR1020110147516A KR20110147516A KR101288958B1 KR 101288958 B1 KR101288958 B1 KR 101288958B1 KR 1020110147516 A KR1020110147516 A KR 1020110147516A KR 20110147516 A KR20110147516 A KR 20110147516A KR 101288958 B1 KR101288958 B1 KR 101288958B1
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alumina
magnesia
coating layer
corrosion resistance
spinel
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KR20130078521A (en
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정용석
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한국산업기술대학교산학협력단
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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/653—Processes involving a melting step
    • C04B35/657—Processes involving a melting step for manufacturing refractories
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/03—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on magnesium oxide, calcium oxide or oxide mixtures derived from dolomite
    • C04B35/04—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on magnesium oxide, calcium oxide or oxide mixtures derived from dolomite based on magnesium oxide
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
    • C04B41/81—Coating or impregnation
    • C04B41/85—Coating or impregnation with inorganic materials
    • C04B41/88—Metals
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
    • C04B2235/3206—Magnesium oxides or oxide-forming salts thereof
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
    • C04B41/4505—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements characterised by the method of application
    • C04B41/4523—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements characterised by the method of application applied from the molten state ; Thermal spraying, e.g. plasma spraying

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  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Coating By Spraying Or Casting (AREA)

Abstract

본 발명은 내식성이 향상된 마그네시아계 내화제품의 제조방법에 관한 것으로, 마그네시아계 내화제품의 표면에 용사코팅공정으로 알루미나를 주된 물질로 포함하는 알루미나계 코팅층을 형성하는 것을 특징으로 한다.
또한, 본 발명에 의한 내식성이 향상된 마그네시아계 내화제품은, 마그네시아계 재질의 내화제품으로서, 그 표면에 알루미나를 주된 물질로 포함하는 알루미나계 코팅층이 도포되며, 상기 알루미나계 코팅층은 용사코팅공정으로 형성되어, 고온의 물체와 접촉할 때 상기 알루미나계 코팅층에 포함된 알루미나가 상기 마그네시아계 재질과 반응하여 MgO-Al2O3 스피넬이 형성되는 것을 특징으로 한다.
본 발명은, 용사코팅공정에 의해 마그네시아계 내화제품의 표면에 알루미나를 주된 물질로 포함하는 알루미나계 코팅층을 형성함으로써, 단순히 알루미나계 코팅층을 형성하는 것에서는 예측할 수 없었던 스피넬상의 형성에 의한 내식성 향상의 효과를 얻을 수 있다.
또한, 높은 가격의 MgO-Al2O3 스피넬을 사용하지 않고 알루미나를 용사코팅하기 때문에, 저렴한 비용으로 마그네시아계 내화제품의 내식성을 크게 높일 수 있는 효과가 있다.The present invention relates to a method of manufacturing a magnesia refractory product with improved corrosion resistance, characterized in that to form an alumina-based coating layer containing alumina as a main material on the surface of the magnesia refractory product by a thermal spray coating process.
In addition, the magnesia refractory product improved corrosion resistance according to the present invention, as a refractory product of magnesia-based material, the alumina-based coating layer containing alumina as the main material is coated on the surface, the alumina-based coating layer is formed by a thermal spray coating process The alumina contained in the alumina-based coating layer reacts with the magnesia-based material to form MgO-Al 2 O 3 spinels when contacted with a high temperature object.
The present invention provides an improvement in corrosion resistance due to the formation of a spinel phase, which was unpredictable in simply forming an alumina coating layer by forming an alumina coating layer containing alumina as a main material on the surface of the magnesia refractory product by a thermal spray coating process. The effect can be obtained.
In addition, since the thermal spray coating of alumina without using a high-priced MgO-Al 2 O 3 spinel, there is an effect that can significantly increase the corrosion resistance of the magnesia-based refractory products at low cost.

Description

내식성이 향상된 마그네시아계 내화제품의 제조방법 및 이에 의해 제조된 마그네시아계 내화제품{MANUFACTURING METHOD OF MAGNESIA-BASED REFRACTORY ARTICLE IMPROVED CORROSION RESISTANCE AND MAGNESIA-BASED REFRACTORY ARTICLE MANUFACTURED THEREBY}Manufacture method of magnesia refractory products with improved corrosion resistance and magnesia refractory products manufactured by the same

본 발명은 내식성이 향상된 내화제품의 제조방법에 관한 것으로, 더욱 자세하게는 내식성이 향상된 마그네시아계 내화제품의 제조방법에 관한 것이다.The present invention relates to a method for producing a refractory product having improved corrosion resistance, and more particularly, to a method for manufacturing a magnesia fire resistant product having improved corrosion resistance.

마그네시아(산화마그네슘, MgO)는 내화재료로서 도가니나 철강업용 전로와 같은 각종 공업요로(工業窯爐, industrial furnace)에 사용되고 있다.Magnesia (magnesium oxide, MgO) is a refractory material and is used in various industrial furnaces such as crucibles and converters for the steel industry.

이러한 마그네시아 내화재료는 융점이 높은 재료이지만, 고온의 슬래그 또는 용융 금속과 접촉하기 때문에 내마모성, 화학적 안정성, 열충격 저항성 등의 우수한 물성뿐만이 아니라 내식성도 뛰어나야 한다.The magnesia refractory material is a material having a high melting point, but should be excellent in corrosion resistance as well as excellent physical properties such as abrasion resistance, chemical stability, and thermal shock resistance because it is in contact with hot slag or molten metal.

종래의 마그네시아계 내화재료는 내식성을 향상시키기 위하여, 여러 가지 물질을 함께 사용하며, 이러한 마그네시아계 내화재료의 대표적인 것으로서, 카본(C)을 첨가한 마그네시아-카본 복합물이 있다. 마그네시아-카본 복합 내화물은 첨가된 카본의 고접촉각을 이용하여 슬래그에 의한 침식을 저지하거나, 마그네시아와 카본의 반응에 의해 발생된 기체 마그네슘의 재산화 과정에서 일어나는 MgO층의 재생성을 통해서 내식성을 향상시킨다.Conventional magnesia-based refractory materials use various materials together to improve corrosion resistance, and are representative of such magnesia-based refractory materials, and there is a magnesia-carbon composite to which carbon (C) is added. Magnesia-carbon composite refractory uses high contact angle of added carbon to prevent erosion by slag or improves corrosion resistance through regeneration of MgO layer during reoxidation of gas magnesium generated by reaction of magnesia and carbon. .

그러나 접촉하는 슬래그나 용융금속에 탄소와 반응하는 물질이 존재하는 경우에는 반응 또는 용해로 인하여 카본이 소실되면서 침식이 발생하는 문제가 있다.However, when there is a material reacting with carbon in the slag or molten metal in contact there is a problem that the erosion occurs as the carbon is lost due to the reaction or melting.

한편, MgO-Al2O3 스피넬은 융점과 열전도도는 높으나 열팽창성이 작고, 염기성 슬래그나 산에 대한 침식저항성이 우수한 물질이다. 이러한 MgO-Al2O3 스피넬은 시멘트 소성용 회전 가마에 처음 사용된 이래로 각종 금속 용해용 도가니, 열전대 보호관, 스테인리스강의 용제로 및 제철제강로 등에 적용할 수 있는 고온 내열 재료로서 유망하게 여겨지고 있다.On the other hand, MgO-Al 2 O 3 spinel is a material having high melting point and thermal conductivity but small thermal expansion and excellent erosion resistance to basic slag or acid. Since the MgO-Al 2 O 3 spinel is first used in a rotary kiln for cement firing, it is considered to be promising as a high temperature heat-resistant material that can be applied to various metal melting crucibles, thermocouple protective tubes, stainless steel solvent furnaces and steelmaking furnaces.

그러나 MgO-Al2O3 스피넬은 제조가 어려워 일반적으로 소결법이나 전융법 등으로 제조되기 때문에 제조비용이 매우 높다. 나아가 소결특성이 좋은 스피넬 분말을 얻기 위한 방법으로 공침법, 동결 건조법, 알콕사이드법 및 에멀젼법과 같은 열수합성법 등의 제조방법이 연구되고 있으나, 모두 제조비용이 높기 때문에 MgO-Al2O3 스피넬은 가격이 매우 비싸다. 따라서 대형 내화제품을 생산할 때에 스피넬을 사용하면 제조비용이 너무 높아지는 문제가 있다.However, MgO-Al 2 O 3 spinel is difficult to manufacture and is generally manufactured by the sintering method or the fusion method, so the manufacturing cost is very high. Furthermore, as a method for obtaining spinel powder having good sintering properties, manufacturing methods such as coprecipitation method, freeze drying method, alkoxide method and emulsion method have been studied, but MgO-Al 2 O 3 spinel is expensive due to high manufacturing cost. This is very expensive. Therefore, when using a spinel when producing a large refractory product there is a problem that the manufacturing cost is too high.

그리고 MgO-Al2O3 스피넬을 내화제품 자체 포함하는 것이 아니라, 마그네시아계 내화제품의 표면에 MgO-Al2O3 스피넬계 코팅을 형성하는 방법이 고려되기도 하였으나, MgO-Al2O3 스피넬의 융점이 매우 높아서 코팅층을 형성하기 어려우며 MgO-Al2O3 스피넬의 높은 가격 또한 계속 문제가 되고 있다.
Although MgO-Al 2 O 3 spinel is not included in the refractory product itself, a method of forming MgO-Al 2 O 3 spinel-based coating on the surface of the magnesia refractory product is considered, but the melting point of MgO-Al 2 O 3 spinel is very high. It is difficult to form a coating layer because it is high, and the high price of MgO-Al 2 O 3 spinel continues to be a problem.

본 발명은 전술한 종래 기술의 문제점을 해결하기 위한 것으로서, 마그네시아계 내화제품의 표면에 알루미나 코팅층을 용사코팅함으로써 내식성을 향상시킨 마그네시아계 내화제품의 제조방법을 제공하는데 그 목적이 있다.
The present invention is to solve the above-mentioned problems of the prior art, an object of the present invention is to provide a method for producing a magnesia refractory product by improving the corrosion resistance by spray coating an alumina coating layer on the surface of the magnesia refractory product.

상기 목적을 달성하기 위한 본 발명에 의한 내식성이 향상된 마그네시아계 내화제품의 제조방법은, 마그네시아계 내화제품의 표면에 용사코팅공정으로 알루미나를 주된 물질로 포함하는 알루미나계 코팅층을 형성하는 것을 특징으로 한다.The manufacturing method of the magnesia refractory product improved corrosion resistance according to the present invention for achieving the above object is characterized in that to form an alumina-based coating layer containing alumina as a main material on the surface of the magnesia-based refractory product by the thermal spray coating process. .

본 발명의 발명자들은 내화제품들은 주로 고온의 슬래그나 용융금속과 접촉하는 환경에서 사용되므로, 가격이 비싼 MgO-Al2O3 스피넬을 직접사용하지 않고 고온의 물질과 접하고 있는 마그네시아계 내화제품의 표면에서 자체적으로 MgO-Al2O3 스피넬을 형성시키는 방법을 연구한 결과, 마그네시아계 내화제품의 표면에 알루미나계 코팅층을 용사코팅하는 방법을 개발하였다.According to the inventors of the present invention, since refractory products are mainly used in an environment of contact with hot slag or molten metal, the surface of the magnesia refractory product which is in contact with a high temperature material without directly using an expensive MgO-Al 2 O 3 spinel. As a result of studying the method of forming MgO-Al 2 O 3 spinel by itself, we have developed a method of spray coating the alumina-based coating layer on the surface of the magnesia refractory products.

알루미나계 코팅층은 알루미나만으로 구성될 수도 있지만, 원활한 용사코팅공정을 위해 알루미나를 여러 가지 물질과 혼합하여 용사코팅을 실시할 수 있으므로 알루미나를 주된 물질로 포함하는 경우라면 특별히 제한되지 않는다.The alumina-based coating layer may be composed of only alumina, but is not particularly limited as long as it contains alumina as a main material because alumina may be mixed with various materials for a smooth spray coating process.

이는 용사코팅공정은 용사과정에서 알루미나 분말이 고온의 열을 받을 뿐만 아니라, 공정을 진행하는 중에 계속하여 코팅층에서 열이 가해지며, 나아가 스피넬을 형성하기에 충분한 알루미나를 포함하는 두께의 코팅층을 형성할 수 있기 때문인 것으로 여겨진다. This is because the thermal spray coating process not only receives the alumina powder from the high temperature heat during the thermal spraying process, but also continuously heats the coating layer during the process, and further forms a coating layer containing alumina sufficient to form the spinel. It is believed to be because.

이때, 알루미나계 코팅층의 두께가 100㎛이상인 것이 바람직하다. 내화제품의 사용과정에서 고온의 슬래그나 용융금속가 접촉하면 표면에 코팅된 알루미나계 코팅층의 일부는 슬래그나 용융금속에 의해 벗겨지므로 두께가 너무 얇으면 스피넬이 형성되지 못한다. 100㎛이상의 두께로 알루미나계 코팅층을 형성하면 일부 코팅층이 없어지더라도 마그네시아계 재질과 반응하여 스피넬을 형성할 수 있다.At this time, the thickness of the alumina-based coating layer is preferably 100㎛ or more. When high temperature slag or molten metal contacts during use of the refractory product, part of the alumina coating layer coated on the surface is peeled off by slag or molten metal, so if the thickness is too thin, the spinel cannot be formed. When the alumina-based coating layer is formed to a thickness of 100 μm or more, the spinel may be formed by reacting with the magnesia-based material even if some of the coating layers disappear.

그리고 용사코팅공정은 1500℃ 이상의 온도로 수행되는 것이 바람직하다. 용사코팅공정의 온도가 낮으면, MgO-Al2O3 스피넬 형성이 어려워진다. 따라서 고온을 이용하는 플라즈마 용사를 통해서 수행되는 것이 좋으며, 플라즈마 용사는 일반적으로 알려진 기술이므로 자세한 설명은 생략한다. And spray coating process is preferably carried out at a temperature of 1500 ℃ or more. If the temperature of the thermal spray coating process is low, MgO-Al 2 O 3 spinel formation becomes difficult. Therefore, it is preferable to perform the plasma spraying using high temperature, and the plasma spraying is generally known, and thus a detailed description thereof will be omitted.

나아가 용사코팅공정으로 알루미나계 코팅층을 형성한 뒤에, 열처리공정을 수행할 수 있다. 본 발명의 제조방법에 의해 제조된 내화제품은 고온의 물질과 접촉하는 과정에서 알루미나계 코팅층에 포함된 알루미나와 마그네시아가 반응하여 MgO-Al2O3 스피넬이 형성되지만, 제조단계에서 열처리를 하여 MgO-Al2O3 스피넬을 미리 형성시킬 수도 있다. 이때 열처리 온도는 1500℃ 이상에서 진행되어야 MgO-Al2O3 스피넬이 형성된다.Furthermore, after the alumina-based coating layer is formed by the thermal spray coating process, a heat treatment process may be performed. In the refractory product prepared by the manufacturing method of the present invention, MgO-Al 2 O 3 spinel is formed by the reaction of alumina and magnesia included in the alumina-based coating layer in the process of contacting with a high temperature material, but MgO by heat treatment in the manufacturing step It is also possible to form -Al 2 O 3 spinels in advance. At this time, the heat treatment temperature is to proceed at 1500 ℃ or more to form MgO-Al 2 O 3 spinel.

열처리 시간은 특별히 제한되지 않으며, 열처리 시간이 길수록 MgO-Al2O3 스피넬이 많이 형성되지만 제조비용이 증가한다. 한편, 본 발명의 제조방법에 의해 제조된 내화제품은 사용과정에서 MgO-Al2O3 스피넬이 생성되므로, 열처리를 하는 것은 사용 초기에 발생하는 침투 및 코팅층의 소실을 막기 위한 것이며, 짧은 열처리 시간으로도 충분한 효과를 얻을 수 있다.The heat treatment time is not particularly limited, and the longer the heat treatment time, the more MgO-Al 2 O 3 spinel is formed, but the manufacturing cost increases. On the other hand, the refractory product produced by the manufacturing method of the present invention is MgO-Al 2 O 3 spinel is produced in the process of use, heat treatment is to prevent the penetration and loss of the coating layer occurs during the initial use, short heat treatment time You can also get enough effect.

본 발명의 다른 실시형태에 의한 내식성이 향상된 마그네시아계 내화제품은, 마그네시아계 재질의 내화제품으로서, 그 표면에 알루미나를 주된 물질로 포함하는 알루미나계 코팅층이 도포되며, 상기 알루미나계 코팅층은 용사코팅공정으로 형성되어, 고온의 물체와 접촉할 때 상기 알루미나계 코팅층에 포함된 알루미나가 상기 마그네시아계 재질과 반응하여 MgO-Al2O3 스피넬이 형성되는 것을 특징으로 한다.The magnesia fireproof product having improved corrosion resistance according to another embodiment of the present invention is a fireproof product made of magnesia material, and an alumina coating layer containing alumina as a main material is coated on the surface thereof, and the alumina coating layer is a thermal spray coating process. When formed in contact with the hot object, the alumina contained in the alumina-based coating layer is characterized in that the MgO-Al 2 O 3 spinel is formed by reacting with the magnesia-based material.

이때, 알루미나계 코팅층의 두께가 100㎛이상인 경우에 MgO-Al2O3 스피넬의 형성이 용이하다.
At this time, when the thickness of the alumina-based coating layer is 100㎛ or more it is easy to form the MgO-Al 2 O 3 spinel.

상술한 바와 같이 구성된 본 발명은, 용사코팅공정에 의해 마그네시아계 내화제품의 표면에 알루미나계 코팅층을 형성함으로써, 단순히 알루미나 코팅층을 형성하는 것에서는 예측할 수 없었던 스피넬상의 형성에 의한 내식성 향상의 효과를 얻을 수 있다.According to the present invention configured as described above, by forming alumina coating layer on the surface of the magnesia fireproof product by the thermal spray coating process, it is possible to obtain the effect of improving the corrosion resistance by the formation of the spinel phase which was unpredictable simply by forming the alumina coating layer. Can be.

또한, 높은 가격의 MgO-Al2O3 스피넬을 사용하지 않고 알루미나를 용사코팅하기 때문에, 저렴한 비용으로 마그네시아계 내화제품의 내식성을 크게 높일 수 있는 효과가 있다.
In addition, since the thermal spray coating of alumina without using a high-priced MgO-Al 2 O 3 spinel, there is an effect that can significantly increase the corrosion resistance of the magnesia-based refractory products at low cost.

도 1은 여러 가지 방법으로 형성된 알루미나계 코팅층을 열처리한 경우에 대한 X-선 회절분석 결과이다.
도 2는 용사코팅된 알루미나계 코팅층의 두께에 따른 X-선 회절분석 결과를 나타낸다.
도 3은 본 실시예에 따라 제조된 마그네시아계 내화제품에 대하여 내침성을 시험한 결과이다.
도 4는 도 3의 시편 (b) 표면에 대한 X-선 회절분석 결과이다.1 is an X-ray diffraction analysis of the heat treatment of the alumina-based coating layer formed by various methods.
Figure 2 shows the results of X-ray diffraction analysis according to the thickness of the spray-coated alumina-based coating layer.
Figure 3 is a result of testing the resistance to the magnesia-based refractory product prepared according to this embodiment.
4 is an X-ray diffraction analysis of the surface of the specimen (b) of FIG.

본 발명에 따른 실시예를 통해서 본 발명을 상세히 설명한다.The present invention will be described in detail through examples according to the present invention.

먼저 마그네시아-카본 내화물의 표면에 다양한 방법으로 알루미나계 코팅층을 형성하고, 표면에 코팅된 알루미나와 반응하여 MgO-Al2O3 스피넬이 형성되는지 여부를 확인하였다.First, the alumina-based coating layer was formed on the surface of the magnesia-carbon refractory by various methods, and it was confirmed whether MgO-Al 2 O 3 spinel was formed by reacting with the alumina coated on the surface.

알루미나계 코팅층을 형성한 방법은 알루미나 페이스트를 도포하여 코팅층을 방법(a), 플라즈마 용사에 의해서 코팅층을 형성하는 방법(b) 및 스퍼터링에 의해서 코팅층을 형성하는 방법(c)을 사용하였다. As a method of forming the alumina-based coating layer, alumina paste was applied to form a coating layer (a), a method of forming a coating layer by plasma spraying (b), and a method of forming a coating layer by sputtering (c).

플라즈마 용사코팅은 일반적으로 사용되는 플라즈마 용사 기술을 사용하였으며, 1500℃ 이상의 온도로 용사가 가능하면 특별히 제한되지 않으므로 자세한 설명은 생략한다.Plasma spray coating used a commonly used plasma spray technology, and if the spray is possible at a temperature of 1500 ℃ or more is not particularly limited, so a detailed description thereof will be omitted.

그리고 마그네시아계 내화제품이 실제로 사용되는 공정온도에서 스피넬이 형성되는지 여부를 확인하기 위하여, 1500℃에서 열처리함으로써 코팅층이 고온의 슬러리 또는 용융 금속과 접촉하는 경우를 재현하였으며, 열처리된 시편에 대하여 X-선 회절분석을 실시하였다.In order to confirm whether the spinel is formed at the process temperature at which the magnesia-based refractory product is actually used, heat treatment at 1500 ° C. reproduces the case where the coating layer is in contact with a hot slurry or molten metal. Line diffraction analysis was performed.

도 1은 여러 가지 방법으로 형성된 알루미나계 코팅층을 열처리한 경우에 대한 X-선 회절분석 결과이다. 1 is an X-ray diffraction analysis of the heat treatment of the alumina-based coating layer formed by various methods.

도시된 것과 같이, 알루미나 페이스트를 도포한 경우(a)와 스퍼터링에 의해 코팅층을 형성한 경우(c)에는 특별한 피크가 나타나지 않았으며, 이로부터 MgO-Al2O3 스피넬이 형성되지 않은 것을 알 수 있다. 반면에 플라즈마 용사에 의해 코팅층을 형성한 경우(b)에는 MgO-Al2O3 스피넬에 해당하는 피크가 강하게 나타난 것을 확인할 수 있다.As shown, in the case of applying the alumina paste (a) and in the case of forming the coating layer by sputtering (c), no special peak appeared, indicating that no MgO-Al 2 O 3 spinel was formed. have. On the other hand, in the case of forming the coating layer by plasma spray (b) it can be seen that the peak corresponding to the MgO-Al 2 O 3 spinel appeared strongly.

이는, 페이스트를 도포한 경우(a)에는 페이스트 제조과정에서 여러 가지 불순물이 포함되어 순수한 알루미나의 양이 적고, 스퍼터링으로 코팅층을 형성한 경우(c)에는 스퍼터링 공정의 특성상 증착된 알루미나의 양이 적기 때문에 스피넬을 형성할 수 있을 만큼의 충분한 알루미나가 코팅되지 않은 것으로 보인다. 또한, 두 경우 모두 코팅층을 형성할 때 고온이 가해지지 않기 때문에 스피넬상이 형성되지 못한 것으로 여겨진다.This means that when the paste is applied (a), various impurities are included in the paste manufacturing process, so that the amount of pure alumina is small, and when the coating layer is formed by sputtering (c), the amount of alumina deposited is small due to the nature of the sputtering process. It seems that not enough alumina has been coated to form the spinel. In both cases, it is believed that the spinel phase was not formed because no high temperature was applied when forming the coating layer.

플라즈마 용사에 의해 알루미나계 코팅층을 형성한 경우(b)에는 원하는 두께가 될 때까지 용사시간을 조절하여 스피넬을 형성하기에 충분한 알루미나 층을 코팅할 수 있다. 또한, 용사되는 알루미나 분말이 고온의 열원으로부터 열을 받을 뿐만 아니라, 원하는 두께를 얻기 위하여 장시간의 용사과정을 거치는 동안에 알루미나계 코팅층에 지속적으로 열이 가해지기 때문에 스피넬이 형성될 수 있는 조건이 갖추어진 것으로 여겨진다.When the alumina-based coating layer is formed by plasma spraying (b), the alumina layer sufficient to form a spinel may be coated by adjusting the spraying time until the desired thickness is achieved. In addition, the sprayed alumina powder not only receives heat from a high temperature heat source, but also heat is continuously applied to the alumina-based coating layer during a prolonged spraying process to obtain a desired thickness, so that spinel can be formed. It is considered to be.

이로부터 용사코팅에 의해 형성된 알루미나계 코팅층은 마그네시아와 반응하여 MgO-Al2O3 스피넬상을 형성하는 것을 확인할 수 있다.
It can be seen that the alumina-based coating layer formed by the spray coating reacts with the magnesia to form the MgO-Al 2 O 3 spinel phase.

그리고 알루미나계 코팅층의 두께에 따른 MgO-Al2O3 스피넬 형성여부를 확인하기 위하여, 플라즈마 용사에 의해서 다양한 두께의 알루미나계 코팅층을 형성하고, 열처리를 한 뒤에 X-선 회절분석을 실시하였다.In addition, in order to confirm the formation of MgO-Al 2 O 3 spinel according to the thickness of the alumina-based coating layer, alumina-based coating layers having various thicknesses were formed by plasma spraying, and subjected to X-ray diffraction analysis after heat treatment.

도 2는 용사코팅된 알루미나계 코팅층의 두께에 따른 X-선 회절분석 결과를 나타낸다. 각 경우의 알루미나계 코팅층의 두께는 (a)가 100㎛이고, (b)가 200㎛이며, (c)가 500㎛이다.Figure 2 shows the results of X-ray diffraction analysis according to the thickness of the spray-coated alumina-based coating layer. The thickness of the alumina coating layer in each case is (a) 100 micrometers, (b) 200 micrometers, and (c) 500 micrometers.

도시된 것과 같이, 모든 알루미나계 코팅층 두께에서 MgO-Al2O3 스피넬에 해당하는 피크가 강하게 나타났다. 따라서 100㎛ 이상의 두께로 알루미나계 코팅층을 용사코팅하는 경우에 MgO-Al2O3 스피넬이 형성된다는 것을 확인할 수 있다.As shown, the peaks corresponding to the MgO-Al 2 O 3 spinel appeared strong at all the alumina-based coating layer thickness. Therefore, it can be seen that the MgO-Al 2 O 3 spinel is formed when the thermal spray coating of the alumina-based coating layer to a thickness of 100㎛ or more.

또한, 본 실시예에 따라 제조된 마그네시아계 내화제품의 내식성 향상을 확인하기 위하여, 고온의 슬래그에 대하여 침투 시험을 실시하였다.In addition, in order to confirm the improvement of the corrosion resistance of the magnesia-based refractory product manufactured according to the present embodiment, a penetration test was performed on the hot slag.

시편은 6%의 카본이 포함된 실린더 모양의 마그네시아-카본 시편(a)과 동일한 시편에 플라즈마 용사에 의해서 100㎛ 두께의 알루미나계 코팅층을 형성한 시편(b)을 준비하였다.Specimen (b) was prepared by forming alumina-based coating layer having a thickness of 100 μm by plasma spraying on the same specimen as the cylindrical magnesia-carbon specimen (a) containing 6% carbon.

그리고 준비된 시편을 CaO-SiO2-Al2O3-MnO 슬래그에 장입하고, 600rpm의 속도로 FRT(finger rotating test)를 실시하였다.The prepared specimen was charged into a CaO-SiO 2 -Al 2 O 3 -MnO slag, and subjected to FRT (finger rotating test) at a speed of 600 rpm.

도 3은 본 실시예에 따라 제조된 마그네시아계 내화제품에 대하여 내침성을 시험한 결과이다.Figure 3 is a result of testing the resistance to the magnesia-based refractory product prepared according to this embodiment.

도시된 것과 같이 플라즈마 용사에 의하여 알루미나계 코팅층이 형성된 시편(b)이 종래의 마그네시아-카본 내화물 시편(a)에 비하여 슬래그의 침투깊이가 얕은 것을 알 수 있으며, 시간이 지날수록 침투깊이의 차이가 더 커지는 확인할 수 있다.As shown, it can be seen that the specimen (b) having the alumina-based coating layer formed by plasma spraying has a shallower penetration depth of slag than the conventional magnesia-carbon refractory specimen (a), and the difference in penetration depth with time is different. You can see it getting bigger.

이는 용사코팅으로 형성된 알루미나계 코팅층이 고온의 슬래그에 접촉하는 과정에서, 코팅층에 포함된 알루미나가 마그네시아-카본 내화물과 반응하여 MgO-Al2O3 스피넬이 형성되었기 때문인 것으로 생각되고, 접촉시간이 증가할수록 반응시간이 길어져 MgO-Al2O3 스피넬의 양이 증가하기 때문에 침투깊이의 차이가 더욱 커진 것으로 여겨진다.This is thought to be due to the formation of MgO-Al 2 O 3 spinel by the reaction of the alumina included in the coating layer with the magnesia-carbon refractory in the process of the alumina-based coating layer formed by the spray coating contact the hot slag, the contact time is increased The longer the reaction time is, the more the MgO-Al 2 O 3 spinel increases, which makes the difference in penetration depth larger.

이러한 침투깊이의 차이가 MgO-Al2O3 스피넬에 의한 것인지 확인하기 위하여, 350분 동안 FRT를 실시한 시편(b)의 표면에 대하여 X-선 회절분석을 수행하였다.X-ray diffraction analysis was performed on the surface of specimen (b) subjected to FRT for 350 minutes to determine whether the difference in penetration depth was due to MgO-Al 2 O 3 spinel.

도 4는 도 3의 시편 (b) 표면에 대한 X-선 회절분석 결과이다.4 is an X-ray diffraction analysis of the surface of the specimen (b) of FIG.

도시된 것과 같이, 고온의 슬래그와 시편의 표면에 MgO-Al2O3 스피넬이 형성된 것으로 나타났으며, 침투깊이의 차이가 MgO-Al2O3 스피넬이 형성에 의한 것임을 확인할 수 있다.
As shown, MgO-Al 2 O 3 spinel was formed on the surface of the hot slag and the specimen, it can be seen that the difference in penetration depth is due to the formation of MgO-Al 2 O 3 spinel.

이상의 결과를 통해서 마그네시아-카본 내화물을 포함하는 마그네시아계 내화물의 표면에 알루미나계 코팅층을 100㎛이상의 두께로 용사코팅하면 마그네시아계 내화물의 내식성이 크게 향상되는 것을 확인하였다.Through the above results, it was confirmed that the corrosion resistance of the magnesia-based refractories is greatly improved by spray coating the alumina-based coating layer to a thickness of 100 µm or more on the surface of the magnesia-based refractory including the magnesia-carbon refractory.

특히, 이러한 효과는 단순히 알루미나계 코팅층을 형성하여서 발생하는 것이 아니고, 용사코팅의 방법을 이용하여 알루미나계 코팅층을 형성할 때 발생하며, 이는 고온의 용사코팅으로 형성된 알루미나계 코팅층이 고온의 슬래그나 용융금속과 접촉하는 과정에서 마그네시아계 내화물과 반응하여 치밀한 구조의 MgO-Al2O3 스피넬이 형성되기 때문이다.In particular, this effect does not occur simply by forming an alumina-based coating layer, but occurs when the alumina-based coating layer is formed using a spray coating method, which is caused by hot slag or melting of an alumina-based coating layer formed by a hot spray coating. This is because a dense structure of MgO-Al 2 O 3 spinel is formed by reaction with the magnesia-based refractory in contact with the metal.

따라서 이러한 결과는 단순히 알루미나계 코팅층을 형성하는 경우에는 예측할 수 없었던 것이며, 이러한 결과를 통해서 얻어진 효과도 예측할 수 없었던 것이다.Therefore, these results were simply unpredictable when the alumina-based coating layer was formed, and the effects obtained through these results could not be predicted.

이상 본 발명을 바람직한 실시예를 통하여 설명하였는데, 상술한 실시예는 본 발명의 기술적 사상을 예시적으로 설명한 것에 불과하며, 본 발명의 기술적 사상을 벗어나지 않는 범위 내에서 다양한 변화가 가능함은 이 분야에서 통상의 지식을 가진 자라면 이해할 수 있을 것이다. 따라서 본 발명의 보호범위는 특정 실시예가 아니라 특허청구범위에 기재된 사항에 의해 해석되어야 하며, 그와 동등한 범위 내에 있는 모든 기술적 사상도 본 발명의 권리범위에 포함되는 것으로 해석되어야 할 것이다.While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Those skilled in the art will understand. Therefore, the scope of protection of the present invention should be construed not only in the specific embodiments but also in the scope of claims, and all technical ideas within the scope of the same shall be construed as being included in the scope of the present invention.

Claims (8)

마그네시아(MgO)계 내화제품의 표면에 용사코팅공정으로 알루미나(Al2O3)를 주된 물질로 포함하는 알루미나계 코팅층을 형성하되,
상기 용사코팅공정 중에 상기 내화제품에 포함된 마그네시아와 상기 알루미나계 코팅층에 포함된 알루미나가 반응하여 MgO-Al2O3 스피넬이 형성되는 것을 특징으로 하는 내식성이 향상된 마그네시아계 내화제품의 제조방법.
Forming an alumina coating layer containing alumina (Al 2 O 3 ) as a main material on the surface of the magnesia (MgO) refractory product by the thermal spray coating process,
MgO-Al 2 O 3 spinel is formed by the reaction of the magnesia contained in the refractory product and the alumina contained in the alumina-based coating layer during the thermal spraying coating process characterized in that the manufacturing method of magnesia-based refractory resistance improved corrosion resistance.
청구항 1에 있어서,
상기 알루미나계 코팅층의 두께가 100㎛이상인 것을 특징으로 하는 내식성이 향상된 마그네시아계 내화제품의 제조방법.
The method according to claim 1,
The method of manufacturing a magnesia-based refractory product having improved corrosion resistance, characterized in that the thickness of the alumina-based coating layer is 100㎛ or more.
청구항 1에 있어서,
상기 용사코팅공정이 1500℃ 이상의 온도로 수행되는 것을 특징으로 하는 내식성이 향상된 마그네시아계 내화제품의 제조방법.
The method according to claim 1,
Method of producing a magnesia-based refractory product improved corrosion resistance characterized in that the thermal spray coating is carried out at a temperature of 1500 ℃ or more.
청구항 1에 있어서,
상기 용사코팅공정이 플라즈마 용사에 의해서 수행되는 것을 특징으로 하는 내식성이 향상된 마그네시아계 내화제품의 제조방법.
The method according to claim 1,
The method of producing a magnesia refractory product improved corrosion resistance characterized in that the spray coating process is carried out by plasma spraying.
청구항 1에 있어서,
상기 용사코팅공정으로 알루미나계 코팅층을 형성한 뒤에, 열처리공정을 수행하는 것을 특징으로 하는 내식성이 향상된 마그네시아계 내화제품의 제조방법.
The method according to claim 1,
After forming the alumina-based coating layer by the thermal spray coating process, the method of manufacturing a magnesia refractory product improved corrosion resistance characterized in that for performing a heat treatment process.
청구항 5에 있어서,
상기 열처리공정이 1500℃ 이상에서 진행되는 것을 특징으로 하는 내식성이 향상된 마그네시아계 내화제품의 제조방법. The method according to claim 5,
Method of producing a magnesia refractory product improved corrosion resistance characterized in that the heat treatment is carried out at 1500 ℃ or more. 마그네시아계 재질의 내화제품으로서,
그 표면에 알루미나를 주된 물질로 포함하는 알루미나계 코팅층이 도포되며,
상기 알루미나계 코팅층은, 용사코팅공정으로 형성되고, 용사코팅공정 중에 상기 알루미나계 코팅층에 포함된 알루미나와 상기 내화제품의 마그네시아가 반응하여 형성된 MgO-Al2O3 스피넬을 포함하는 것을 특징으로 하는 내식성이 향상된 마그네시아계 내화제품.
As a fireproof product made of magnesia
On the surface is applied an alumina-based coating layer containing alumina as a main material,
The alumina-based coating layer is formed by a spray coating process, corrosion resistance characterized in that it comprises a MgO-Al 2 O 3 spinel formed by the reaction of the alumina contained in the alumina-based coating layer and the magnesia of the refractory product during the thermal spray coating process This improved magnesia fireproof product.
청구항 7에 있어서,
상기 알루미나계 코팅층의 두께가 100㎛이상인 것을 특징으로 하는 내식성이 향상된 마그네시아계 내화제품.The method of claim 7,
The magnesia-based fire resistance product with improved corrosion resistance, characterized in that the thickness of the alumina-based coating layer is 100㎛ or more.
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US3927223A (en) * 1972-05-11 1975-12-16 Asahi Glass Co Ltd Method of forming refractory oxide coatings
KR0178116B1 (en) * 1996-12-27 1999-03-20 이재운 Method of manufacturing magnesia porous material

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3927223A (en) * 1972-05-11 1975-12-16 Asahi Glass Co Ltd Method of forming refractory oxide coatings
KR0178116B1 (en) * 1996-12-27 1999-03-20 이재운 Method of manufacturing magnesia porous material

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