JP2002348174A - HEATER MATERIAL CONTAINING MoSi2 AS ITS MAIN COMPONENT WITH LOW-OXYGEN DIFFUSE VITREOUS COATING FILM - Google Patents
HEATER MATERIAL CONTAINING MoSi2 AS ITS MAIN COMPONENT WITH LOW-OXYGEN DIFFUSE VITREOUS COATING FILMInfo
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- Prior art keywords
- mosi
- vitreous
- ppm
- main component
- base material
- Prior art date
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Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
- H05B2203/018—Heaters using heating elements comprising mosi2
Landscapes
- Resistance Heating (AREA)
- Ceramic Products (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、MoSi2基材ま
たはMoSi2を主成分として70%以上含む基材から
成る(以下併せてMoSi2を主体とするという)発熱
材料に関するものであり、特には発熱材料の表面に形成
されるガラス質表面酸化被膜を低酸素拡散性にした発熱
材料に関する。The present invention relates generally relates to the heat generating material consisting of a substrate comprising more than 70% of MoSi 2 substrate or MoSi 2 as a main component (hereinafter referred to collectively as a main component MoSi 2), in particular The present invention relates to a heat generating material in which a vitreous surface oxide film formed on the surface of the heat generating material has low oxygen diffusivity.
【0002】[0002]
【従来の技術】MoSi2基発熱材料は、1000〜1
800°Cの酸化性雰囲気下で耐酸化性に優れたガラス
質表面酸化被膜(以下ガラス質被膜と呼ぶ)を形成する
ため、酸化性雰囲気の超高温域まで使用できる数少ない
発熱材料の一つである。MoSi2基発熱材料の成分
は、抵抗値調整、成型助剤またはガラス質被膜の生成助
剤等のためMoSi2に数%〜数十%の多成分系のガラ
ス成分等が添加されている。MoSi2基材は表面酸化
あるいはコーティング等の適切な方法でガラス質の保護
被膜を形成させた後、ヒーターとして使用されるのが通
常である。またMoSi2基発熱材料は例えば図1のよ
うな形状に加工した後、炉体に装着され、ヒーターとし
て使用される。 2. Description of the Related Art MoSi 2- based heat-generating materials are 1000-1.
It is one of the few heat-generating materials that can be used up to the ultra-high temperature range of an oxidizing atmosphere to form a vitreous surface oxide film (hereinafter referred to as a vitreous film) having excellent oxidation resistance in an oxidizing atmosphere at 800 ° C. is there. As the components of the MoSi 2 -based heat-generating material, several to several tens% of a multi-component glass component is added to MoSi 2 to adjust the resistance value, aid in molding, or aid in forming a vitreous film. The MoSi 2 substrate is usually used as a heater after forming a vitreous protective film by an appropriate method such as surface oxidation or coating. Further, the MoSi 2 based heat generating material is processed into a shape as shown in FIG. 1 and then mounted on a furnace body to be used as a heater.
【0003】図中の(a)は電極部と呼ばれ、MoSi
2基材と完全な電気的接続をするためガラス質被膜を取
り除いた母材に通常Al等の金属が溶射されている。電
極部は、MoSi2基発熱体を抵抗加熱する時の端子の
役割を担う。また図の(b)はグリップ部と呼ばれ、
(c)の発熱部より径を太くすることにより抵抗を下
げ、抵抗発熱を迎えている。グリップ部は発熱部との電
極部間に熱勾配を生じさせ、電極部が高温にさらされ酸
化されることを防止している。図の(c)は発熱部と呼
ばれ、まさに炉を昇温する時のヒーターの役割を担う。[0003] (a) in the figure is called an electrode part, and it is MoSi.
Metals such as Al are usually sprayed onto the base material from which the vitreous coating has been removed in order to make complete electrical connection with the two substrates. The electrode portion serves as a terminal when the MoSi 2- based heating element is resistance-heated. (B) of the figure is called a grip part,
The resistance is lowered by making the diameter larger than that of the heat generating part in FIG. The grip portion generates a thermal gradient between the electrode portion and the heat generating portion, thereby preventing the electrode portion from being exposed to a high temperature and being oxidized. (C) in the figure is called a heating part, and just plays the role of a heater when heating the furnace.
【0004】[0004]
【発明が解決しようとする課題】従来のMoSi2基発
熱材料を電気炉の発熱体(ヒーター)として使用する場
合、大別すると二つの問題点が挙げられる。一つは、3
00〜600°Cの酸化性雰囲気下で長時間保持された
MoSi2基発熱材料は、1000〜1800°Cの領
域で生じる酸化挙動と異なり、ガラス質被膜中を拡散し
てきた酸素によりMoとSiの同時酸化を起こし酸化物
粉末を生成し、ペストと呼ばれる粉状化現象を引き起こ
すことである。この現象は一般に抵抗発熱体のグリップ
部で多く見られ、しばしば通電不良を起こし発熱体の破
断の原因となる。もう一つは、抵抗発熱体を繰り返し昇
降温しながら使用すると発熱部の径が減少し、発熱体性
能が劣化することである。ここでいう性能劣化は、発熱
部の径が初期状態より細くなり抵抗値に変化が生じるこ
とや、発熱部の表面積が小さくなり炉の昇温速度に支障
をきたすこと等である。本発明の課題は、上記の問題点
を改良し、耐ペスト性に優れ、且つ長期間性能が劣化し
ないMoSi2を主体とする発熱材料を提供することで
ある。When a conventional MoSi 2 -based heat-generating material is used as a heating element (heater) for an electric furnace, there are roughly two problems. One is three
The MoSi 2 -based exothermic material held for a long time in an oxidizing atmosphere of 00 to 600 ° C. is different from the oxidation behavior occurring in the region of 1000 to 1800 ° C., in that Mo and Si are diffused by oxygen diffused in the vitreous film. Is caused by the simultaneous oxidation of the oxides to form an oxide powder, which causes a powdering phenomenon called plague. This phenomenon is generally observed in the grip portion of the resistance heating element, and often causes a failure in energization and causes the heating element to break. Another is that when the resistance heating element is used while repeatedly raising and lowering the temperature, the diameter of the heating section is reduced, and the performance of the heating element is deteriorated. The performance degradation here means that the diameter of the heat-generating portion becomes smaller than the initial state, causing a change in the resistance value, or that the surface area of the heat-generating portion becomes small, which hinders the rate of temperature rise of the furnace. An object of the present invention is to improve the above-mentioned problems, to provide a heat-generating material mainly composed of MoSi 2 which has excellent plague resistance and does not deteriorate in performance for a long time.
【0005】[0005]
【課題を解決するための手段】本発明者らは、上記の課
題を解決するために鋭意研究を行った結果、以下のよう
な知見を得た。従来のMoSi2基発熱材料でペスト現
象や径の減少が生じる原因は、MoSi2基発熱材料の
表面に生成されるガラス質被膜の耐酸化特性が必ずしも
十分でないためである。そのため課題を解決するために
は、耐酸化性に十分に優れたガラス質被膜を生成する発
熱材料に改善する必要がある。すなわち、一般にガラス
質被膜形成による耐酸化特性の向上は、ガラス質被膜の
低酸素拡散性によるものである。ガラス質被膜中の酸素
拡散は、図2(a)に示すようなガラス質被膜の三次元
構造の隙間を酸素分子が移動することによって行われ
る。Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have obtained the following findings. The cause of the plague phenomenon and the decrease in diameter in the conventional MoSi 2 -based heat generating material is that the oxidation resistance of the vitreous coating formed on the surface of the MoSi 2 -based heat generating material is not always sufficient. Therefore, in order to solve the problem, it is necessary to improve the heat generating material to generate a vitreous film having sufficiently excellent oxidation resistance. That is, generally, the improvement of the oxidation resistance by the formation of the vitreous film is due to the low oxygen diffusivity of the vitreous film. Oxygen diffusion in the vitreous coating is performed by the movement of oxygen molecules in gaps in the three-dimensional structure of the vitreous coating as shown in FIG.
【0006】そして、ガラス中にある種の不適合成分、
たとえばAlが存在する場合には、図2(b)に示すよ
うに三次元網目構造が断ち切られ網目の隙間が拡大され
ることになる。その結果三次元網目構造の隙間を酸素分
子が移動・拡散し易くなるため耐酸化性が劣化するので
ある。そして、従来のMoSi2基発熱材料の場合に
は、これらの不適合成分含有量については特別な管理は
行われておらず、耐酸化性の低下をもたらす原因となっ
ていたことが判明した。不適合成分として、Al、C
a、Mg、Na、K、P、Pb、Mn等を確認すること
ができた。従って、MoSi2基原料および抵抗値調節
等のために加えられる原料として、これらの不適合成分
含有量の低い高純度原料を使用することにより網目の細
かいガラス質被膜を生成する発熱材料となり、上記の問
題を解決し得ることが分かった。And certain incompatible components in the glass,
For example, when Al is present, the three-dimensional network structure is cut off as shown in FIG. As a result, oxygen molecules easily move and diffuse in the gaps of the three-dimensional network structure, so that the oxidation resistance deteriorates. In the case of the conventional MoSi 2 -based heat generating material, it has been found that no special management is performed on the content of these incompatible components, and this is a cause of a reduction in oxidation resistance. Al, C as incompatible components
a, Mg, Na, K, P, Pb, Mn, etc. could be confirmed. Therefore, by using a high-purity raw material having a low incompatible component content as a MoSi 2 base raw material and a raw material added for resistance value adjustment, etc., the material becomes a heat generating material that produces a vitreous film with a fine mesh. It turns out that the problem can be solved.
【0007】この知見に基づき、本発明は、 1.MoSi2基材またはMoSi2を主成分として7
0%以上含む基材から成る発熱材料において、基材中に
含まれるAl、Ca、Mg、Naの含有量がそれぞれ1
00ppm以下であることを特徴とする発熱材料。 2.MoSi2基材またはMoSi2を主成分として7
0%以上含む基材から成る発熱材料において、基材中に
含まれるAl、Ca、Mg、Na、K、P、Pb、Mn
の含有量がそれぞれ100ppm以下であることを特徴
とする発熱材料。 3.MoSi2基材またはMoSi2を主成分として7
0%以上含む基材から成る発熱材料において、基材中に
含まれるAl、Ca、Mg、Na、K、Li、Ba、
B、P、Pb、Mn、Znの含有量がそれぞれ100p
pm以下であることを特徴とする発熱材料。を提供する
ものである。Based on this finding, the present invention provides: MoSi 2 base material or MoSi 2 as main component 7
In a heat-generating material composed of a base material containing 0% or more, the contents of Al, Ca, Mg, and Na contained in the base material are each 1
A heat-generating material characterized by being at most 00 ppm. 2. MoSi 2 base material or MoSi 2 as main component 7
In a heat-generating material composed of a base material containing 0% or more, Al, Ca, Mg, Na, K, P, Pb, Mn contained in the base material
The heat-generating material is characterized in that the content of each is 100 ppm or less. 3. MoSi 2 base material or MoSi 2 as main component 7
In a heat-generating material comprising a base material containing 0% or more, Al, Ca, Mg, Na, K, Li, Ba,
The content of B, P, Pb, Mn, and Zn is 100 p each.
pm or less. Is provided.
【0008】MoSi2基材中に含まれる不適合成分を
低減することにより、ガラス質被膜の、三次元網目構造
の隙間の拡大が抑制される。そのためガラス質被膜の、
三次元網目構造中の酸素分子の移動も制限される。その
結果、耐酸化性は大幅に向上することになるのである。[0008] By reducing the incompatible component contained in the MoSi 2 substrate, the expansion of the gap of the three-dimensional network structure of the vitreous coating is suppressed. Therefore, the vitreous coating,
The movement of oxygen molecules in the three-dimensional network is also restricted. As a result, the oxidation resistance is greatly improved.
【0009】[0009]
【発明の実施の形態】本発明は、MoSi2基材または
MoSi2を主成分として70%以上含む基材を対象と
する。本発明の目的では、適当な酸化物や珪化物を成分
として選択することによってMoSi2の含有量を約7
0%まで低減させることができるので、MoSi2を主
成分として70%以上含む基材もここでは含めた。基材
の製法は問わない。基材の形態も任意である。また、こ
の基材と同種のものを被覆材として用いることもでき
る。DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a MoSi 2 substrate or a substrate containing 70% or more of MoSi 2 as a main component. For the purposes of the present invention, the content of MoSi 2 is reduced to about 7 by selecting appropriate oxides and silicides as components.
Since it can be reduced to 0%, a base material containing 70% or more of MoSi 2 as a main component is also included here. The method of manufacturing the substrate is not limited. The form of the substrate is also arbitrary. In addition, the same type as the base material can be used as the coating material.
【0010】抵抗発熱体として使用する場合、適当な方
法により棒状に成型し焼成を行う。必要に応じて添加成
分(ガラス成分等)を添加するが、重要なことは、Mo
Si 2および必要に応じて使用される添加成分のいずれ
も不適合成分、すなわち、Al、Ca、Mg、Na等を
極力低減した高純度の原料を使用することである。Mo
Si2基材焼結体中に含まれるAl、Ca、Mg、Na
の含有量は、それぞれ100ppm以下とすべきであ
る。また、K、P、Pb、Mn、さらには、Li、B
a、B、Znについてもそれぞれの成分の含有量が10
0ppm以下とすべきである。さらに、望ましくは、こ
れらの不適合成分の合計量が1000ppm以下、好ま
しくは100ppm以下とすべきである。[0010] When used as a resistance heating element,
It is shaped into a rod by the method and fired. Add as necessary
(Glass components, etc.), but the important thing is
Si 2And any of the additional components used as needed
Also incompatible components, ie, Al, Ca, Mg, Na, etc.
The use of highly purified raw materials that has been reduced as much as possible. Mo
Si2Al, Ca, Mg, Na contained in the substrate sintered body
Should be less than 100 ppm each.
You. In addition, K, P, Pb, Mn, and further, Li, B
a, B, and Zn also have a content of each component of 10
It should be below 0 ppm. Further, preferably
The total amount of these unsuitable components is 1000 ppm or less, preferably
Or less than 100 ppm.
【0011】そして、MoSi2基材には適当な方法に
より表面酸化被膜の形成処理を施す、通常は、1000
〜1800°Cにおいて酸化性雰囲気下で表面の酸化に
よりガラス質被膜を形成する。図2(b)に示したよう
に、基材中に上述した不適合元素が多く存在すると、形
成されたガラス質被膜の三次元網目構造が断ち切られ網
目の隙間が拡大されることになり、その結果三次元網目
構造の隙間を酸素分子が移動・拡散し易くなるためガラ
ス質被膜の耐酸化性が劣化するのであるが、基材中の不
適合成分の含有量をそれぞれ100ppm以下と規制す
ることにより、生成するガラス質被膜を低酸素拡散性に
することが可能となる。The MoSi 2 substrate is subjected to a surface oxide film forming treatment by an appropriate method.
A glassy film is formed by oxidizing the surface in an oxidizing atmosphere at ~ 1800 ° C. As shown in FIG. 2 (b), when a large amount of the above-mentioned incompatible elements are present in the base material, the three-dimensional network structure of the formed vitreous film is cut off, and the gaps of the network are enlarged. As a result, the oxidation resistance of the vitreous coating deteriorates because oxygen molecules easily move and diffuse in the gaps of the three-dimensional network structure.However, by controlling the content of the incompatible components in the base material to 100 ppm or less, respectively. In addition, it becomes possible to make the resulting vitreous coating have low oxygen diffusivity.
【0012】[0012]
【実施例】以下、実施例に基づいて説明するが、本発明
は実施例によって制限されるものではない。また、実施
例と対比して比較例も示す。 a.グリップ部の耐ペスト性試験 (実施例1)高純度原料粉末を使用して、MoSi2−
15%SiO2焼結体からなる直径9mmのMoSi2
基発熱体を作製した。このMoSi2基発熱体の化学分
析値を表1に示す。不適合成分はいずれも20ppm以
下であった。The present invention will be described below with reference to examples, but the present invention is not limited to the examples. Further, a comparative example is also shown in comparison with the example. a. Example 1 Pest resistance test of grip part (Example 1) MoSi 2 −
9 mm diameter MoSi 2 made of 15% SiO 2 sintered body
A base heating element was prepared. Table 1 shows the chemical analysis values of the MoSi 2- based heating element. The incompatible components were all 20 ppm or less.
【0013】(比較例1)また、比較のため従来のMo
Si2基発熱体を用意した。同様に、このMoSi 2基
発熱体の化学分析値を表1に示す。表1のように不適合
成分であるAlは3300ppm、Ca560ppm、
Mg740ppmであり、いずれも本発明の範囲外であ
った。Comparative Example 1 For comparison, a conventional Mo was used.
Si2A base heating element was prepared. Similarly, this MoSi 2Base
Table 1 shows the chemical analysis values of the heating element. Non-conforming as shown in Table 1
Al as a component is 3300 ppm, Ca 560 ppm,
Mg 740 ppm, both of which are outside the scope of the present invention.
Was.
【0014】[0014]
【表1】 [Table 1]
【0015】これらについて、耐ペスト試験を行った。
各発熱体は100mmの長さに切断し、ガラス質被膜が
形成されていない両端の切断面は酸化防止剤を塗布し
た。各発熱材料は図3に示す温度サイクル(200〜4
80°C)を繰り返す大気炉内に放置しガラス質被膜で
覆われた母材が粉状にペストしていく程度を比較した。
その結果、実施例1では、80サイクル終了後でも健全
であった。一方、比較例1では25サイクル後にガラス
質被膜を透過した酸素により母材でMoとSiの同時酸
化が生じ、表面近傍が粉状化しガラス質被膜が剥離し
た。These were subjected to a plague resistance test.
Each heating element was cut into a length of 100 mm, and an antioxidant was applied to the cut surfaces at both ends where no vitreous coating was formed. Each heat-generating material was subjected to the temperature cycle shown in FIG.
(80 ° C.) was repeated, and the degree to which the base material covered with the vitreous film was plastered in a powder state was compared.
As a result, Example 1 was sound even after the completion of 80 cycles. On the other hand, in Comparative Example 1, Mo and Si were simultaneously oxidized in the base material due to oxygen transmitted through the vitreous coating after 25 cycles, and the vicinity of the surface was powdered, and the vitreous coating was separated.
【0016】(実施例2)高純度のMoSi2と異なる
不適合成分を含むSiO2を用いて、MoSi2−10
%SiO2焼結体からなる、直径9mm、長さ100m
mのMoSi2基発熱体を作製した。このMoSi2基
発熱体の化学分析値を表2に示す。不適合成分はいずれ
も100ppm以下であった。[0016] with (Example 2) SiO 2 containing pure MoSi 2 different incompatible ingredients, MoSi 2 -10
% SiO 2 sintered body, diameter 9mm, length 100m
m MoSi 2- based heating elements were prepared. Table 2 shows the chemical analysis values of the MoSi 2- based heating element. The incompatible components were all less than 100 ppm.
【0017】(比較例2、3)高純度のMoSi2と異
なる不適合成分を含むSiO2を用いて、MoSi2−
10%SiO2焼結体からなる、直径9mm、長さ10
0mmのMoSi2基発熱体を作製した。このMoSi
2基発熱体の化学分析値を同様に、表2に示す。表2の
ように比較例2の不適合成分であるAlは330pp
m、Ca380ppm、Mg68ppm、比較例3の不
適合成分であるAlは1200ppm、Ca210pp
m、Mg260ppmであり、いずれも本発明の範囲外
であった。[0017] (Comparative Examples 2 and 3) with SiO 2 which contains high-purity MoSi 2 different incompatible ingredients, MoSi 2 -
9 mm in diameter and 10 in length made of 10% SiO 2 sintered body
A 0 mm MoSi 2- based heating element was produced. This MoSi
Table 2 also shows the chemical analysis values of the two heating elements. As shown in Table 2, the incompatible component Al of Comparative Example 2 was 330 pp.
m, Ca 380 ppm, Mg 68 ppm, Al which is an incompatible component of Comparative Example 3 was 1200 ppm, Ca 210 pp
m and Mg were 260 ppm, both of which were outside the scope of the present invention.
【0018】[0018]
【表2】 [Table 2]
【0019】これらについて実施例1と同様の方法で耐
ペスト試験を行った。その結果、実施例2では、80サ
イクル終了後に表面に僅かに粉状の酸化物が生じる程度
であった。一方、比較例2では70サイクル後に、比較
例3は35サイクル後に表面近傍が激しく粉状化しガラ
ス質被膜が剥離した。These were subjected to a plague resistance test in the same manner as in Example 1. As a result, in Example 2, a slight powdery oxide was generated on the surface after 80 cycles. On the other hand, in Comparative Example 2, after 70 cycles, and in Comparative Example 3 after 35 cycles, the vicinity of the surface was violently powdered and the vitreous film was peeled off.
【0020】b.ガラス質被膜の成長速度試験 (実施例3)MoSi2−5%SiO2焼結体からなる
直径4mmのMoSi2基発熱体を作製した。このMo
Si2基発熱体の化学分析値を表3に示す。表3のよう
に、不適合成分はいずれも16ppm以下であった。B. Growth rate tests glassy coating was produced (Example 3) MoSi 2 -5% MoSi 2 groups 4mm diameter of SiO 2 sintered body heating element. This Mo
Table 3 shows the chemical analysis values of the Si 2- based heating element. As shown in Table 3, the incompatible components were all 16 ppm or less.
【0021】[0021]
【表3】 [Table 3]
【0022】(比較例4)また、比較のため従来のMo
Si2基発熱体を用意した。このMoSi2基発熱体の
化学分析値を同様に、表3に示す。比較例4の不適合成
分であるAlは2600ppm、Ca530ppm、M
g570ppm、Na130ppmであり、いずれも本
発明の範囲外であった。Comparative Example 4 For comparison, a conventional Mo was used.
It was prepared Si 2 group heating elements. Table 3 also shows the chemical analysis values of this MoSi 2- based heating element. Al which is an incompatible component of Comparative Example 4 was 2600 ppm, Ca 530 ppm, and M
g of 570 ppm and Na of 130 ppm, all of which were out of the range of the present invention.
【0023】本試験では、ガラス質被膜の成長速度を測
定することにより高温でのガラス質被膜の耐酸化性を比
較した。試験手順は、まず発熱体を抵抗加熱により16
50°Cまで昇温し、大気中で10、30、90、12
0時間保持した後室温に戻した。そして、発熱体のガラ
ス質被膜の膜厚を求めるため、フッ酸に浸漬し表面のガ
ラス質被膜を溶解した。ガラス質被膜の膜厚は、溶解前
後の発熱体の径を測定し、その差から算出した。165
0°Cの保持時間に対するガラス質被膜の膜厚変化を図
4に示した。In this test, the oxidation resistance of the vitreous coating at high temperatures was compared by measuring the growth rate of the vitreous coating. The test procedure consists of first heating the heating element by resistance heating.
The temperature is raised to 50 ° C., and the air temperature is 10, 30, 90, 12
After holding for 0 hours, the temperature was returned to room temperature. Then, in order to determine the thickness of the vitreous film of the heating element, the vitreous film on the surface was dissolved by immersion in hydrofluoric acid. The thickness of the vitreous film was calculated from the difference between the diameters of the heating element before and after melting, and the difference. 165
FIG. 4 shows the change in the thickness of the vitreous film with respect to the holding time at 0 ° C.
【0024】比較例4では、ガラス質被膜中を酸素が拡
散しやすく耐酸化性が不十分のため、120時間後の膜
厚は42μmであった。一方、本発明品である実施例3
では低酸素拡散性のガラス質被膜を有するため、酸化の
進行を意味するガラス被膜の成長を抑制し、ともに16
μm以下であった。一般にガラス質被膜はある厚み以上
に成長すると、発熱体を昇降温する時に生じる熱歪み等
の影響で母材表面から剥離する。剥離後の新生面には新
たにガラス質被膜が生成され、そのガラス質被膜は成長
を重ねるが、ある厚み以上でまた剥離する。このサイク
ルにより発熱体の径が次第に減少し発熱部の性能劣化が
生じる。本発明品は、低酸素拡散性ガラス被膜であるた
め被膜の成長速度を抑制する。すなわち、本発明品はガ
ラス質被膜が剥離する膜厚まで成長するのに長時間を要
し、発熱部の径が減少するサイクルを著しく低速化し、
長期間性能劣化が生じない発熱体となる。In Comparative Example 4, since the oxygen easily diffused in the vitreous film and the oxidation resistance was insufficient, the film thickness after 120 hours was 42 μm. On the other hand, Example 3 which is the product of the present invention
Has a low oxygen diffusive glassy film, so that the growth of the glass film, which indicates the progress of oxidation, is suppressed.
μm or less. Generally, when the vitreous film grows to a certain thickness or more, the vitreous film peels off from the surface of the base material under the influence of thermal distortion or the like generated when the temperature of the heating element is raised or lowered. A new vitreous film is newly formed on the new surface after peeling, and the vitreous film grows again, but peels again at a certain thickness or more. Due to this cycle, the diameter of the heating element gradually decreases, and the performance of the heating section deteriorates. Since the product of the present invention is a low oxygen diffusive glass film, the growth rate of the film is suppressed. In other words, the product of the present invention requires a long time to grow to a thickness at which the vitreous coating is peeled off, and the cycle in which the diameter of the heat generating portion decreases is remarkably slowed down.
The heating element does not cause performance degradation for a long time.
【0025】c.最高使用温度試験 (実施例4)高純度原料粉末を使用して、MoSi2−
5%SiO2焼結体からなる直径4mm、長さ200m
mのMoSi2基発熱体を作製した。このMoSi2基
発熱体の化学分析値を表4に示す。表4のように、不適
合成分はいずれも38ppm以下であった。C. Maximum service temperature test (Example 4) Using high purity raw material powder, MoSi 2 −
4mm diameter, 200m length made of 5% SiO 2 sintered body
m MoSi 2- based heating elements were prepared. Table 4 shows the chemical analysis values of the MoSi 2- based heating element. As shown in Table 4, the incompatible components were all at 38 ppm or less.
【0026】[0026]
【表4】 [Table 4]
【0027】(比較例5)また、比較のため従来のMo
Si2基発熱体を用意した。このMoSi2基発熱体の
化学分析値を同様に、表3に示す。比較例5の不適合成
分であるAlは3300ppm、Ca560ppm、M
g740ppmであり、いずれも本発明の範囲外であっ
た。Comparative Example 5 For comparison, a conventional Mo was used.
It was prepared Si 2 group heating elements. Table 3 also shows the chemical analysis values of this MoSi 2- based heating element. Al which is an incompatible component of Comparative Example 5 was 3300 ppm, Ca 560 ppm, and M
g of 740 ppm, which were out of the range of the present invention.
【0028】これらについて最高使用温度付近での高温
耐酸化性試験を行った。試験は、抵抗加熱により165
0°Cまで60秒で昇温し、そこから1825°Cまで
0.5°C/secで加熱するプログラムを用意した。
ただし昇温中破断もしくはガラス質被膜が破壊された場
合は、その時点で終了とした。温度管理は放射温度計に
より、行った。実施例4の本発明品では、1825°C
到達後300秒保持してもガラス質被膜表面の変化は見
られなかった。一方、比較例5の従来材では1750°
C付近で内部酸化により発生したガス成分の吹き出しが
生じ、ガラス質被膜が破壊された。These were subjected to a high temperature oxidation resistance test near the maximum service temperature. The test was performed with 165 by resistance heating.
A program was prepared in which the temperature was raised to 0 ° C. in 60 seconds and then heated to 1825 ° C. at 0.5 ° C./sec.
However, if the glass film was broken or the vitreous film was broken during the heating, the process was terminated at that point. Temperature control was performed with a radiation thermometer. In the product of the present invention of Example 4, 1825 ° C
No change was observed on the surface of the vitreous coating even after the arrival for 300 seconds. On the other hand, in the conventional material of Comparative Example 5, 1750 °
Blowing of the gas component generated by the internal oxidation occurred near C, and the vitreous film was destroyed.
【0029】d.化学反応性試験 上記の実施例4及び比較例5と同一のサンプルを用い
て、耐火煉瓦等に用いられるジルコニアおよびシリマイ
トと大気中1650°Cで接触させ化学反応性を調べる
試験を行った。その結果、本発明品は、耐火物との接触
部で反応は起こらないが、不適合成分がガラス質被膜に
含まれる従来材は、それらの耐火物と反応し融着した。
電気炉の発熱体として使用する場合、耐火煉瓦等との融
着は破損の原因となるため、この点においても本発明品
の性質が優れていることが明らかである。D. Chemical Reactivity Test Using the same sample as in Example 4 and Comparative Example 5, a test was conducted in which zirconia and sillimite used for refractory bricks and the like were brought into contact at 1650 ° C. in the atmosphere to examine the chemical reactivity. As a result, the product of the present invention did not react at the contact portion with the refractory, but the conventional material containing the incompatible component contained in the vitreous coating reacted with the refractory and fused.
When used as a heating element of an electric furnace, fusion with a refractory brick or the like causes breakage, and it is clear that the properties of the product of the present invention are also excellent in this regard.
【0030】[0030]
【発明の効果】本発明の不適合成分含有量を低減した低
酸素拡散性ガラス質被膜を有するMoSi2を主体とす
る発熱材料は、耐ペスト性に優れ、酸化の進行を意味す
るガラス被膜の成長を抑制し、最高使用温度付近での高
温耐酸化性及び化学反応性にも優れ、長期間でも性能の
劣化が少ないものである。According to the present invention, the heat-generating material mainly composed of MoSi 2 having a low oxygen diffusible vitreous coating having a reduced content of an incompatible component has excellent resistance to plague and the growth of the glass coating which means that the oxidation proceeds. And excellent in high-temperature oxidation resistance and chemical reactivity near the maximum use temperature, and there is little deterioration in performance even over a long period of time.
【図1】MoSi2基からなる電気炉用発熱体(ヒータ
ー)の模式図である。FIG. 1 is a schematic diagram of a heating element (heater) for an electric furnace composed of two MoSis.
【図2】(a)は、ガラス質被膜の三次元網目構造を示
す説明図、そして(b)は三次元網目構造が断ち切られ
網目の隙間が拡大された状態を示す説明図である。FIG. 2A is an explanatory diagram showing a three-dimensional network structure of a vitreous coating, and FIG. 2B is an explanatory diagram showing a state in which the three-dimensional network structure is cut off and a mesh gap is enlarged.
【図3】耐ペスト試験で使用した繰り返し加熱試験の温
度サイクル(200〜480°C)を示すグラフであ
る。FIG. 3 is a graph showing a temperature cycle (200 to 480 ° C.) of a repeated heating test used in a plague resistance test.
【図4】大気中1650°Cの保持時間に対するガラス
質被膜の膜厚変化を示すグラフである。FIG. 4 is a graph showing a change in thickness of a vitreous film with respect to a holding time at 1650 ° C. in the atmosphere.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 高垣 大輔 茨城県北茨城市華川町臼場187番地4 株 式会社ジャパンエナジー磯原工場内 (72)発明者 大橋 建夫 茨城県北茨城市華川町臼場187番地4 株 式会社ジャパンエナジー磯原工場内 Fターム(参考) 3K092 PP09 QA01 QB11 QB24 RA05 VV09 4G001 BA04 BA49 BB49 BB71 BD01 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Daisuke Takagaki 187-4 Usaba, Hanakawa-cho, Kitaibaraki-shi, Ibaraki Inside Japan Energy Isohara Plant Co., Ltd. 187-4 Japan Energy Corporation Isohara Factory F-term (reference) 3K092 PP09 QA01 QB11 QB24 RA05 VV09 4G001 BA04 BA49 BB49 BB71 BD01
Claims (3)
分として70%以上含む基材から成る発熱材料におい
て、基材中に含まれるAl、Ca、Mg、Naの含有量
がそれぞれ100ppm以下であることを特徴とする発
熱材料。1. A heating material comprising a MoSi 2 base material or a base material containing 70% or more of MoSi 2 as a main component, wherein the contents of Al, Ca, Mg, and Na contained in the base material are each 100 ppm or less. A heat-generating material, characterized in that:
分として70%以上含む基材から成る発熱材料におい
て、基材中に含まれるAl、Ca、Mg、Na、K、
P、Pb、Mnの含有量がそれぞれ100ppm以下で
あることを特徴とする発熱材料。2. A heating material comprising a MoSi 2 base material or a base material containing 70% or more of MoSi 2 as a main component, wherein Al, Ca, Mg, Na, K,
A heat-generating material, wherein the content of each of P, Pb, and Mn is 100 ppm or less.
分として70%以上含む基材から成る発熱材料におい
て、基材中に含まれるAl、Ca、Mg、Na、K、L
i、Ba、B、P、Pb、Mn、Znの含有量がそれぞ
れ100ppm以下であることを特徴とする発熱材料。3. A heat generating material consisting of MoSi 2 substrate containing 70% or more of the substrate or MoSi 2 as a main component, Al contained in the substrate, Ca, Mg, Na, K , L
A heat-generating material, wherein the content of each of i, Ba, B, P, Pb, Mn, and Zn is 100 ppm or less.
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Cited By (4)
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JP2004307243A (en) * | 2003-04-04 | 2004-11-04 | Nikko Materials Co Ltd | MoSi2 POWDER, PRODUCING METHOD THEREFOR, HEATING ELEMENT USING THE SAME AND METHOD FOR PRODUCING HEATING ELEMENT |
JP2010143823A (en) * | 2010-01-29 | 2010-07-01 | Nippon Mining & Metals Co Ltd | MoSi2 POWDER, METHOD FOR PRODUCING THE SAME, HEATING ELEMENT USING THE POWDER, AND METHOD FOR PRODUCING THE HEATING ELEMENT |
JP2016115620A (en) * | 2014-12-17 | 2016-06-23 | 日本電気硝子株式会社 | Exothermic body and manufacturing method of the same |
JP2021510003A (en) * | 2018-03-18 | 2021-04-08 | サンドビック インテレクチュアル プロパティー アクティエボラーグ | Heating element containing chromium alloyed molybdenum dissilicate and its use |
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JPH11317282A (en) * | 1998-02-20 | 1999-11-16 | Riken Corp | Molybdenum disilicide composite ceramic heating element and its manufacture |
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JPH10324571A (en) * | 1997-05-23 | 1998-12-08 | Riken Corp | Molybdenum disilicide ceramic heat generating body and its production |
JPH11317282A (en) * | 1998-02-20 | 1999-11-16 | Riken Corp | Molybdenum disilicide composite ceramic heating element and its manufacture |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2004307243A (en) * | 2003-04-04 | 2004-11-04 | Nikko Materials Co Ltd | MoSi2 POWDER, PRODUCING METHOD THEREFOR, HEATING ELEMENT USING THE SAME AND METHOD FOR PRODUCING HEATING ELEMENT |
JP4515038B2 (en) * | 2003-04-04 | 2010-07-28 | 日鉱金属株式会社 | MoSi2 powder, method for producing the powder, heating element using the powder, and method for producing the heating element |
JP2010143823A (en) * | 2010-01-29 | 2010-07-01 | Nippon Mining & Metals Co Ltd | MoSi2 POWDER, METHOD FOR PRODUCING THE SAME, HEATING ELEMENT USING THE POWDER, AND METHOD FOR PRODUCING THE HEATING ELEMENT |
JP2016115620A (en) * | 2014-12-17 | 2016-06-23 | 日本電気硝子株式会社 | Exothermic body and manufacturing method of the same |
JP2021510003A (en) * | 2018-03-18 | 2021-04-08 | サンドビック インテレクチュアル プロパティー アクティエボラーグ | Heating element containing chromium alloyed molybdenum dissilicate and its use |
JP7015397B2 (en) | 2018-03-18 | 2022-02-02 | サンドビック インテレクチュアル プロパティー アクティエボラーグ | Heating elements containing chromium alloyed molybdenum dissilicate and its use |
US11866371B2 (en) | 2018-03-18 | 2024-01-09 | Sandvik Intellectual Property Ab | Heating element comprising chromium alloyed molybdenum disilicide and the use thereof |
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