JP3178628B2 - Insulating coating film - Google Patents
Insulating coating filmInfo
- Publication number
- JP3178628B2 JP3178628B2 JP32243892A JP32243892A JP3178628B2 JP 3178628 B2 JP3178628 B2 JP 3178628B2 JP 32243892 A JP32243892 A JP 32243892A JP 32243892 A JP32243892 A JP 32243892A JP 3178628 B2 JP3178628 B2 JP 3178628B2
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- Prior art keywords
- coating film
- vol
- thermal expansion
- aggregate
- coefficient
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Description
【０００１】[0001]
【産業上の利用分野】本発明は断熱性を有する塗膜に関
する。この塗膜は、例えば、内燃機関で用いられるエキ
ゾーストマニホールド等の排気系機器の様に高温域で使
用される機器に適用できる。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-insulating coating film. This coating film can be applied to equipment used in a high temperature range, such as exhaust system equipment such as an exhaust manifold used in an internal combustion engine.
【０００２】[0002]
【従来の技術】特開昭５８−９９１８０号公報には、ジ
ルコニアの粉末粒子とコロイダルシリカ等の無機系バイ
ンダーとフリットとの混和物からなるスラリーを用い、
高温の排気ガスに触れる鋳鉄等の金属製機器の内面にス
ラリー膜を形成し、そのスラリー膜を固化して、断熱性
をもつ塗膜を形成する事項が開示されている。2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 58-99180 discloses the use of a slurry composed of a mixture of zirconia powder particles, an inorganic binder such as colloidal silica, and a frit,
It discloses that a slurry film is formed on the inner surface of a metal device such as cast iron that is exposed to high-temperature exhaust gas, and the slurry film is solidified to form a heat-insulating coating film.
【０００３】また、従来より、Ｆｅ2 Ｏ3 の粉末粒子と
水ガラス等のバインダーとを混合したベンガラと呼ばれ
る液状塗料が用いられ、その液状塗料を鋼材の表面に塗
布し、固化させ、塗膜を形成し、これにより鋼材の表面
の耐食性を確保することにしている。[0003] Conventionally, a liquid paint called "Vengara" in which powder particles of Fe 2 O 3 and a binder such as water glass are mixed has been used, and the liquid paint is applied to the surface of a steel material, solidified, and solidified. Is formed, thereby ensuring the corrosion resistance of the surface of the steel material.
【０００４】[0004]
【発明が解決しようとする課題】ところで、高温域で用
いられる膜は、母材との熱膨張差が小さい方が好まし
い。ここで２０〜８００°Ｃの領域におけるジルコニア
の熱膨張率は１０×１０-6であり、アルミナの９×１０
-6よりも大きいものの、金属（鋼、鋳鉄：１１×１０-6
〜１４×１０-6）に比べて小さい。そのため、塗膜と母
材との熱膨張差が不可避的に生じる。この場合、昇温、
冷却が繰り返して行われると、塗膜の損傷、剥離が生じ
易い。特に、内燃機関で用いられる排気系機器では、昇
温、冷却が繰り返して行われるので、塗膜の損傷、剥離
が生じ易い。Incidentally, it is preferable that a film used in a high temperature region has a small difference in thermal expansion from a base material. Here, the thermal expansion coefficient of zirconia in the range of 20 to 800 ° C. is 10 × 10 −6 , and that of alumina is 9 × 10 −6.
Although greater than -6, metal (steel, cast iron: 11 × 10 -6
１４14 × 10 −6 ). Therefore, a difference in thermal expansion between the coating film and the base material inevitably occurs. In this case, the temperature rise,
When cooling is repeatedly performed, damage and peeling of the coating film are likely to occur. In particular, in an exhaust system device used in an internal combustion engine, since the temperature is raised and cooled repeatedly, the coating film is easily damaged or peeled.
【０００５】また、前記したベンガラ塗料で形成された
塗膜は、常温域において用いられるものにすぎない。更
に、ベンガラ塗料で形成された塗膜の構成要素であるＦ
ｅ2 Ｏ3 の熱膨張率は１３×１０-6と高く、金属母材に
近いが、この塗膜に占めるＦｅ2 Ｏ3 の粉末粒子の体積
割合は、小さい。その理由は、塗料の塗り易さ、長期の
保管性を追求するため、液状塗料中の粉体比を１０ｖｏ
ｌ％以下に抑え、塗料の粘度の上昇や硬化速度の上昇を
抑止しており、固化後の塗膜でも粉体比は２０ｖｏｌ％
以下である。図３は、ベンガラ塗料で形成された塗膜
（粉体比は２０ｖｏｌ％）の組織を模式的に示す。図３
から理解できる様に、バインダーに白抜きで描かれた粒
子が島状に配置されている。なお、図３において島状の
黒色部分は気孔を示す。[0005] Further, the coating film formed by the above-mentioned red paint is only used in a normal temperature range. Further, F, which is a component of the coating film formed by the red paint,
The thermal expansion coefficient of e 2 O 3 is as high as 13 × 10 −6, which is close to that of the metal base material, but the volume ratio of the Fe 2 O 3 powder particles in the coating film is small. The reason is that the powder ratio in the liquid paint must be 10 vol. In order to pursue ease of coating and long-term storage.
1% or less to suppress the increase in the viscosity of the paint and the increase in the curing speed. Even in the solidified coating film, the powder ratio is 20 vol%.
It is as follows. FIG. 3 schematically shows the structure of a coating film (powder ratio: 20 vol%) formed with red iron oxide paint. FIG.
As can be understood from FIG. 2, the particles drawn in white on the binder are arranged in an island shape. In FIG. 3, black island-shaped portions indicate pores.
【０００６】上記した様にベンガラ塗料で形成された塗
膜は、粉体比が小さいため、Ｆｅ2Ｏ3 の高熱膨張性が
十分に期待できず、塗膜の熱膨張率を金属母材の熱膨張
率に適合させるのは期待できない。また、塗膜固化の際
に、塗料中に大量に占めるバインダーが収縮するために
塗膜の内部に亀裂が生じ、使用の際に、この亀裂が起点
となり塗膜の剥離が発生し易い。[0006] As described above, since the coating film formed of the red iron oxide paint has a small powder ratio, the high thermal expansion property of Fe 2 O 3 cannot be sufficiently expected, and the thermal expansion coefficient of the coating film is reduced by the metal base material. It cannot be expected to match the coefficient of thermal expansion. Further, when the coating film is solidified, the binder occupying a large amount in the coating material shrinks, so that a crack is generated inside the coating film. When the coating is used, the crack is a starting point, and the coating film is easily peeled.
【０００７】本発明は上記した実情に鑑みなされたもの
であり、その目的は、金属母材に熱膨張率を適合でき、
耐剥離性を高め得る、高温域で使用される、断熱性を有
する塗膜を提供することにある。[0007] The present invention has been made in view of the above-described circumstances, and an object of the present invention is to make it possible to adapt the coefficient of thermal expansion to a metal base material,
An object of the present invention is to provide a heat-insulating coating film which can be used in a high temperature range and which can enhance peel resistance.
【０００８】[0008]
【課題を解決するための手段】本発明者は上記した目的
のもとに鋭意開発を進め、ＦｅＯ、Ｆｅ2 Ｏ3 及びＦｅ
3 Ｏ4 の酸化鉄は熱伝達率が小さく塗膜の断熱性を期待
できること、ＦｅＯ、Ｆｅ2 Ｏ3 及びＦｅ3 Ｏ4 の酸化
鉄の粉末粒子を主要成分とするセラミックス粉末の塗膜
における体積割合を高めれば、塗膜の熱膨張率を金属母
材の熱膨張率に適合させ易いことに着目し、本発明の塗
膜を完成したものである。The inventor of the present invention has intensively developed the above-mentioned object, and has proposed FeO, Fe 2 O 3 and Fe 2 O 3.
The iron oxide of 3 O 4 has a small heat transfer coefficient and can be expected to have the heat insulating property of the coating film, and the volume of the ceramic powder containing iron oxide powder particles of FeO, Fe 2 O 3 and Fe 3 O 4 as a main component By focusing on the fact that the thermal expansion coefficient of the coating film can easily be adapted to the thermal expansion coefficient of the metal base material when the ratio is increased, the coating film of the present invention is completed.
【０００９】本発明に係る断熱性を有する塗膜は、Ｆｅ
Ｏ、Ｆｅ2 Ｏ3 及びＦｅ3 Ｏ4 の少なくとも１種からな
る酸化鉄の粉末粒子を主要成分とするセラミックス粉末
と、残部が無機バインダーとで構成された高温域で使用
される塗膜であり、塗膜の体積を１００ｖｏｌ％とした
とき、セラミックス粉末粒子は、塗膜における粒子間接
合性を高めるように５０ｖｏｌ％以上に設定されてお
り、セラミックス粉末粒子を１００ｖｏｌ％としたと
き、酸化鉄は２０ｖｏｌ％以上に設定されており、２０
〜８００℃における熱膨張率は１１．５×１０-6〜１
６．５×１０-6に設定されていることを特徴とするもの
である。熱膨張率は線膨張率を意味する。The heat-insulating coating film according to the present invention comprises Fe
A coating film used in a high-temperature region, comprising a ceramic powder mainly composed of iron oxide powder particles composed of at least one of O, Fe 2 O 3 and Fe 3 O 4 , and the balance being an inorganic binder. When the volume of the coating film is 100 vol%, the ceramic powder particles are set to 50 vol% or more so as to enhance the interparticle bonding property in the coating film. When the ceramic powder particles are 100 vol%, iron oxide is 20% by volume or more
The coefficient of thermal expansion at ~ 800 ° C is 11.5 × 10 -6 -1
It is characterized by being set to 6.5 × 10 -6 . The coefficient of thermal expansion means the coefficient of linear expansion.
【００１０】セラミックス粉末は、ＦｅＯ、Ｆｅ2 Ｏ3
及びＦｅ3 Ｏ4 の少なくとも１種からなる酸化鉄の粉末
粒子を主要成分とする。塗膜の体積を１００ｖｏｌ％と
したとき、セラミックス粉末粒子が占める体積割合は５
０ｖｏｌ％以上に設定されている。ここで、セラミック
ス粉末粒子を混ぜただけでは、ベンガラ塗料で形成され
た塗膜と同様に、塗膜に占めるセラミックス粉末粒子の
体積割合は３０ｖｏｌ％を越えず、せいぜい２０ｖｏｌ
％程度である。体積割合を高める有効な手段は、例え
ば、粒径が小さなセラミックス粉末粒子を混ぜて用いた
り、界面活性剤等の分散剤を用いて粉末粒子を分散さ
せ、その凝集を防止することである。The ceramic powder is FeO, Fe 2 O 3
And iron oxide powder particles composed of at least one of Fe 3 O 4 as a main component. When the volume of the coating film is 100 vol%, the volume ratio occupied by the ceramic powder particles is 5 %.
It is set to 0 vol% or more. Here, just by mixing the ceramic powder particles, the volume ratio of the ceramic powder particles in the coating film does not exceed 30 vol%, and is at most 20 vol, as in the case of the coating film formed by the Bengala paint.
%. An effective means for increasing the volume ratio is to mix and use ceramic powder particles having a small particle diameter, or to disperse the powder particles using a dispersant such as a surfactant to prevent aggregation.
【００１１】また本発明では、セラミックス粉末中で酸
化鉄が占める割合は、セラミックス粉末粒子全体を１０
０ｖｏｌ％としたとき、酸化鉄の粉末粒子が占める体積
割合は２０ｖｏｌ％以上に設定されている。In the present invention, the proportion of iron oxide in the ceramic powder is such that the entirety of the ceramic powder particles is 10%.
When 0 vol%, the volume ratio occupied by the iron oxide powder particles is set to 20 vol% or more.
【００１２】[0012]
【作用】本発明に係る塗膜は粉体比が高いので、塗膜に
おける粉体粒子の接合性が増し、塗膜の熱膨張率は金属
母材の熱膨張率に近づく。The coating according to the present invention has a high powder ratio, so that the bondability of the powder particles in the coating increases, and the coefficient of thermal expansion of the coating approaches that of the metal base material.
【００１３】[0013]
〔試験例１〕 （母材）母材としては、鋳鉄製テストピース（径３０ｍ
ｍ、長さ２０ｍｍ）を用い、ショットブラスト処理によ
り粗面化し、表面粗さＲｚ７０μとし、テストピースの
頂面をコ−ティング面とする。なお、ショットブラスト
処理は、１００μのアルミナグリッド材を用いた。[Test Example 1] (Base material) As a base material, a cast iron test piece (diameter 30 m) was used.
m, length 20 mm), and the surface is roughened by shot blasting to have a surface roughness Rz of 70 μm, and the top surface of the test piece is used as a coating surface. In the shot blasting, a 100 μm alumina grid material was used.
【００１４】（塗料）セラミックス粉末として、粒度が
１〜２μｍのＦｅ2 Ｏ3 の微粉末と、粒度が２０〜４０
μｍのＦｅ2 Ｏ3 の粗粉末とを用いた。そして、微粉
末：粗粉末が重量比で３０：７０となる様にＶ型混粉機
で混粉したものを原料骨材とした。また、Ｎａ2 Ｏ・Ｓ
ｉＯ2 を蒸留水により溶かした水ガラス水溶液（濃度３
０ｗｔ％）を準備し、これをバインダー溶液とした。(Paint) As a ceramic powder, a fine powder of Fe 2 O 3 having a particle size of 1-2 μm and a powder having a particle size of 20-40
μm of coarse powder of Fe 2 O 3 was used. Then, a mixture obtained by mixing with a V-type mixer so that the ratio of the fine powder to the coarse powder was 30:70 by weight was used as a raw material aggregate. Na 2 O · S
Water glass aqueous solution in which iO 2 was dissolved in distilled water (concentration 3
0 wt%) was prepared and used as a binder solution.
【００１５】そして、原粉骨材とバインダー溶液を体積
比で５０：５０となる様に混合し、これに骨材重量を１
００ｗｔ％としたとき、５ｗｔ％の割合で分散剤を添加
し十分に攪拌し、スラリー状の塗料を作製した。分散剤
はポリカルボン酸基を有する市販品（サイノプコ株式会
社 ＳＮディスパーサント５０４０）である。この添加
により、骨材同士つまりＦｅ2 Ｏ3 粉末粒子の凝集が防
止されると共に、Ｆｅ2 Ｏ3 粉末粒子とバインダーとの
濡れ性が向上し、これにより５０ｖｏｌ％もの大量の骨
材つまりＦｅ2 Ｏ3 粉末を有するスラリー原料の作製が
可能となった。Then, the raw powder aggregate and the binder solution are mixed in a volume ratio of 50:50, and the weight of the aggregate is added to the mixture.
When the content was set to 00 wt%, a dispersant was added at a ratio of 5 wt%, and the mixture was sufficiently stirred to produce a slurry-like coating. The dispersant is a commercially available product having a polycarboxylic acid group (Synopco SN Dispersant 5040). This addition, the agglomeration of the aggregate to each other, that Fe 2 O 3 powder particles can be prevented, Fe 2 O 3 wettability between powder particles and the binder is improved, thereby 50 vol% ones large amount of aggregate, i.e. Fe 2 A slurry raw material having O 3 powder can be produced.
【００１６】（塗布）前記した鋳鉄製テストピースの頂
面に、この塗料を刷毛にてコ−ティングした。コ−ティ
ング後、室温にて乾燥させ、表面の水分が蒸発したのを
確認した後、２００℃の乾燥炉にテストピースを投入
し、約２時間乾燥させた。この工程により、バインダー
中の水ガラスは硬化反応を生じ、皮膜は硬化する。乾燥
後、皮膜膜厚を測定したところ、１００μｍであった。
更に、上記の工程をもう一度繰り返し再び、膜厚を測定
したところ３００μｍとなっていた為、処理を完了し
た。(Coating) The paint was coated with a brush on the top surface of the test piece made of cast iron. After coating, the coating was dried at room temperature, and after confirming that the water on the surface had evaporated, the test piece was put into a drying oven at 200 ° C. and dried for about 2 hours. In this step, the water glass in the binder undergoes a curing reaction, and the film is cured. After drying, the film thickness was measured and found to be 100 μm.
Further, the above steps were repeated once again, and the film thickness was measured again.
【００１７】（焼成）上記の処理をしたテストピースを
大気炉に投入し、５００℃にて５時間、焼成し、以て塗
膜を形成した。この処理は、バインダーの反応を終了さ
せることを目的とするものである。以上の処理により塗
膜は形成される。 （組織観察）試験例１で作製した塗膜は、外観からは剥
離、亀裂等の不具合は認められなかった。また、塗膜を
縦に切断し、電子顕微鏡で断面組織を観察したが、母材
と塗膜との界面部位にも亀裂は認められなかった。(Firing) The test piece subjected to the above treatment was put into an atmospheric furnace and baked at 500 ° C. for 5 hours to form a coating film. This treatment is intended to end the reaction of the binder. A coating film is formed by the above processing. (Texture observation) The coating film produced in Test Example 1 did not show any defects such as peeling and cracking from the appearance. Further, the coating film was cut vertically, and the cross-sectional structure was observed with an electron microscope. As a result, no crack was observed at the interface between the base material and the coating film.
【００１８】（塗膜における骨材の体積割合の測定）塗
膜における骨材の占める面積率に基づき、塗膜における
骨材の占める体積割合を求めた。具体的には、画像解析
処理機（ニコレ株式会社、型式ルーゼックスＩＩＩ）を
用い、骨材部とバインダー部に見かけ上、濃淡差が生じ
ることを利用し、一定面積に占める両者の割合を測定し
た。これをそれぞれの試料について５〜１０ケ所測定
し、平均をとった。その結果、塗膜における骨材の体積
割合、つまり、固化状態の塗膜の体積を１００ｖｏｌ％
としたとき、Ｆｅ2 Ｏ3 粉末粒子の割合は６５ｖｏｌ％
であった。(Measurement of Volume Ratio of Aggregate in Coating Film) Based on the area ratio of the aggregate in the coating film, the volume ratio of the aggregate in the coating film was determined. Specifically, using an image analysis processing machine (Nicolet Co., Ltd., model Luzex III), the ratio of both to a certain area was measured by utilizing the fact that a difference in shade appears between the aggregate portion and the binder portion. . This was measured for 5 to 10 places for each sample, and the average was taken. As a result, the volume ratio of the aggregate in the coating film, that is, the volume of the coating film in a solidified state is 100 vol%.
, The proportion of the Fe 2 O 3 powder particles is 65 vol%
Met.
【００１９】〔形態〕本発明の対象としている母材は、
高温での使用に耐え得る金属材料であり、具体的には鋳
鉄、鋼材及びステンレス等の鉄系材料、あるいは、Ｎ
ｉ、Ｃｏを主成分とするインコネル等の高耐熱金属材料
である。本発明では、前述した様にこれらの金属母材と
塗膜との熱膨張率をマッチングさせるため、熱膨張率が
大きいＦｅ2 Ｏ3 等の酸化鉄を主要成分とする骨材を使
用しているものである。しかし、上記金属材料の熱膨張
率はＦｅ2 Ｏ3 等の酸化鉄のそれと必ずしも一致するも
のではなく、他材料粉末粒子を塗膜に添加し、母材と塗
膜との熱膨張率のマッチングを図ることがより好ましい
場合もある。以下、マッチングの形態の例について説明
する。[Form] The base material targeted by the present invention is:
A metal material that can withstand use at high temperatures, specifically, iron-based materials such as cast iron, steel and stainless steel, or N
It is a high heat-resistant metal material such as Inconel containing i and Co as main components. In the present invention, as described above, in order to match the coefficient of thermal expansion between the metal base material and the coating film, an aggregate containing iron oxide such as Fe 2 O 3 having a large coefficient of thermal expansion as a main component is used. Is what it is. However, the coefficient of thermal expansion of the metal material does not always match that of iron oxide such as Fe 2 O 3, and powder particles of another material are added to the coating to match the coefficient of thermal expansion between the base material and the coating. In some cases, it is more preferable to achieve the above. Hereinafter, an example of the matching mode will be described.
【００２０】即ち、表１は、塗膜の体積を１００ｖｏｌ
％としたとき粉末粒子の体積割合が５０％の場合におい
て、塗膜の熱膨張率が各種金属母材とマッチングする様
に作製した形態を示す。粉末粒子のこの体積割合では塗
膜中で大部分の粒子が接合してつながっており、粒子の
熱膨張率が実質的に塗膜の熱膨張率であると把握でき
る。ここで、酸化鉄の熱膨張率は、２０〜８００°Ｃに
おいて、ＦｅＯが１３×１０-6、Ｆｅ2 Ｏ3 が１３×１
０-6、Ｆｅ3 Ｏ4 が１６．５×１０-6であり、このう
ち、最も熱膨張率が大きなものがＦｅ3 Ｏ4 である。That is, Table 1 shows that the volume of the coating film is 100 vol.
%, When the volume ratio of the powder particles is 50%, the form is such that the coefficient of thermal expansion of the coating film is matched with various metal base materials. At this volume ratio of the powder particles, most of the particles in the coating film are joined and connected, and it can be understood that the thermal expansion coefficient of the particles is substantially the thermal expansion coefficient of the coating film. Here, at 20 to 800 ° C., the thermal expansion coefficient of iron oxide is 13 × 10 −6 for FeO and 13 × 1 for Fe 2 O 3.
0 -6, Fe 3 O 4 is 16.5 × 10 -6, Among them, the most thermal expansion coefficient is large is Fe 3 O 4.
【００２１】[0021]
【表１】 [Table 1]
【００２２】表１のＮｏ．Ａに示す様に、母材が鋳鉄
（ＦＣ２０）である場合には、骨材をＦｅ2 Ｏ3 １００
ｖｏｌ％とすれば、マッチングが図られる。Ｎｏ．Ｂに
示す様に、母材がニレジスト鋳鉄である場合には、骨材
をＦｅ3 Ｏ4 １００ｖｏｌ％とすれば、マッチングが図
られる。Ｎｏ．Ｃに示す様に、母材が熱膨張率の比較的
小さなフェライト系ステンレス鋼（ＳＵＳ４３０）であ
る場合には、骨材をＦｅ2 Ｏ3 が５０ｖｏｌ％、ＺｒＯ
2 が５０ｖｏｌ％とすれば、マッチングが図られられ
る。或いは、Ｎｏ．Ｄに示す様に、母材が同じくフェラ
イト系ステンレス鋼（ＳＵＳ４３０）である場合には、
骨材をＦｅ2 Ｏ3 が６３ｖｏｌ％、Ａｌ2 Ｏ3 が３７ｖ
ｏｌ％とすれば、マッチングが図られる。Ｎｏ．Ｅに示
す様に母材がフェライト系ステンレス鋼（ＳＵＳ４３
０）である場合には、骨材をＦｅ3 Ｏ4が２０ｖｏｌ
％、ＺｒＯ2 が８０ｖｏｌ％とすれば、マッチングが図
られる。Ｎｏ．Ｆに示す様に母材がＮｉ系合金（Ｉｎｃ
ｏｎｅｌ６００）である場合には、骨材をＦｅ3 Ｏ4 が
８３ｖｏｌ％、ＺｒＯ2 が１７ｖｏｌ％とすれば、マッ
チングが図られる。No. 1 in Table 1. As shown in A, when the base material is cast iron (FC20), the aggregate is made of Fe 2 O 3 100
If it is vol%, matching is achieved. No. As shown in B, when the base material is niresist cast iron, matching can be achieved if the aggregate is 100 vol% Fe 3 O 4 . No. As shown in C, when the base material is ferritic stainless steel (SUS430) having a relatively small coefficient of thermal expansion, the aggregate is made of 50 vol% of Fe 2 O 3 and ZrO.
If 2 is 50 vol%, matching is achieved. Or, No. As shown in D, when the base material is also ferritic stainless steel (SUS430),
63 vol% of Fe 2 O 3 and 37 v of Al 2 O 3
ol%, matching can be achieved. No. As shown in E, the base material is ferritic stainless steel (SUS43
If it is 0), the aggregate Fe 3 O 4 is 20vol
% And ZrO 2 at 80 vol%, matching is achieved. No. As shown in F, the base material is a Ni-based alloy (Inc.
(e.g., onel 600), matching can be achieved if the aggregate is 83 vol% Fe 3 O 4 and 17 vol% ZrO 2 .
【００２３】上記したＮｏ．Ｃ、Ｎｏ．Ｄ、Ｎｏ．Ｅで
は、母材として熱膨張率の比較的小さなフェライト系ス
テンレス（ＳＵＳ４３０）を用いた場合であり、この場
合には、熱膨張率のマッチングのために、ＺｒＯ2 （熱
膨張率１０×１０-6）、Ａｌ2 Ｏ3 （熱膨張率９．０×
１０-6）を用いている。 〔試験例２〕塗膜に占める骨材の体積割合を変化させ、
どのような影響を及ぼすか測定した。測定に用いたセラ
ミックス粉末及びバインダーとしては、試験例１で用い
たものと同様のものを用いた。The above No. C, No. D, No. In E, a ferritic stainless steel (SUS430) having a relatively small coefficient of thermal expansion is used as a base material. In this case, ZrO 2 (coefficient of thermal expansion 10 × 10 − ) is used to match the coefficient of thermal expansion. 6 ), Al 2 O 3 (coefficient of thermal expansion 9.0 ×)
10 -6 ) is used. [Test Example 2] Changing the volume ratio of the aggregate in the coating film,
The effect was measured. The same ceramic powder and binder as those used in Test Example 1 were used for the measurement.
【００２４】その結果を表２に示す。表２に示す様に、
どのテストピースでも、固化後の塗膜における骨材の体
積割合は、スラリーにおける骨材の体積割合に比べて増
加している。その理由は、バインダー中の水分の蒸発及
び固化によるものである。また、固化前後での骨材の割
合の関係を図１において○印で示す。図１の実線に係る
特性線Ｗ１は、スラリー中の水分等の蒸発成分が完全に
蒸発し、塗膜が理想的に収縮した時の関係を示す。図１
においてどの○印も特性線Ｗ１を下回っているのは、塗
膜が完全に収縮することはなく、内部に気孔が発生する
ため骨材の割合が低下したものと思われる。Table 2 shows the results. As shown in Table 2,
In each test piece, the volume ratio of the aggregate in the coating film after solidification is increased as compared with the volume ratio of the aggregate in the slurry. The reason is due to the evaporation and solidification of the water in the binder. Further, the relationship between the ratio of the aggregate before and after the solidification is indicated by a circle in FIG. The characteristic line W1 according to the solid line in FIG. 1 shows the relationship when the evaporation component such as moisture in the slurry completely evaporates and the coating film contracts ideally. FIG.
The reason why all of the circles are below the characteristic line W1 is that the coating film did not completely shrink, and pores were generated inside, so that the ratio of the aggregate decreased.
【００２５】また、図１における○印に示す様に、固化
後の塗膜において、骨材の割合が約６６ｖｏｌ％以上に
上がらない理由は、粒子の圧密化が進んでも粒子間に３
０ｖｏｌ％の空隙が不可避的に出来てしまうためであ
る。骨材の体積割合と塗膜状態との関係を説明する。即
ち、表２から理解できる様に、骨材の体積割合と塗膜状
態との関係を見ると、スラリー中の骨材の体積割合が１
５ｖｏｌ％以下（固化後の塗膜における骨材比が２５ｖ
ｏｌ％以下）では、塗膜の内部に亀裂が発生している。
これは、この範囲ではバインダーが多いため塗膜の収縮
量が大きくなるためであると考えられる。また、この範
囲では、塗膜に含まれる気孔の気孔径も大きく、使用中
の亀裂発生の起点となる可能性が高い。 固化後の塗膜
における骨材であるＦｅ2 Ｏ3 粉末粒子の体積割合が５
０ｖｏｌ％以上になると、電子顕微鏡による観察で、粒
子間接合が発生しており、粒子と粒子とが接している。
この場合、Ｆｅ2 Ｏ3 粉末粒子の熱膨張率は実質的に塗
膜の熱膨張率とみることができる。As shown by the circles in FIG. 1, the reason that the ratio of the aggregate in the solidified coating film does not increase to about 66 vol% or more is that even if the consolidation of the particles progresses, three particles exist between the particles.
This is because a void of 0 vol% is inevitably formed. The relationship between the volume ratio of the aggregate and the state of the coating film will be described. That is, as can be understood from Table 2, the relationship between the volume ratio of the aggregate and the state of the coating film indicates that the volume ratio of the aggregate in the slurry is 1%.
5 vol% or less (Aggregate ratio in the coating film after solidification is 25 v
ol% or less), cracks are generated inside the coating film.
This is considered to be because in this range, the amount of binder is large and the amount of shrinkage of the coating film is large. Further, in this range, the pore diameter of the pores contained in the coating film is large, and it is highly likely that the pores will be the starting points of crack generation during use. When the volume ratio of the Fe 2 O 3 powder particles as the aggregate in the solidified coating film is 5
When the content is 0 vol% or more, interparticle bonding has occurred by observation with an electron microscope, and the particles are in contact with each other.
In this case, the coefficient of thermal expansion of the Fe 2 O 3 powder particles can be substantially regarded as the coefficient of thermal expansion of the coating film.
【００２６】しかし、５０ｖｏｌ％以下では粒子と粒子
との間にバインダーである水ガラスが存在し、粒子と水
ガラスとの両材料の平均値が塗膜の熱膨張率となってし
まう。そればかりか、両材料の熱膨張率差によって、粒
子とバインダーとの間に亀裂を発生させることもある。
図２は、塗膜を１００ｖｏｌ％としたときＦｅ2 Ｏ3 粉
末粒子の体積割合が５０ｖｏｌ％で形成された塗膜を、
電子顕微鏡で観察した構造を模式的に示すものである。
図２に示す様に、この塗膜では、粒径が比較的大きな粗
粉末粒子１０間の空隙部分を、粒径が微小な微粉末粒子
１２が埋めているため、粉末粒子の体積割合は高いもの
であり、その間にバインダー１４が配置されている。な
お黒色の島状部分は気孔１６である。図２から理解でき
る様に、この塗膜では、粒子間接合が発生しており、前
述した様に、Ｆｅ2 Ｏ3 粉末粒子の熱膨張率は実質的に
塗膜の熱膨張率とみることができる。図４はＦｅ2 Ｏ3
粉末粒子の体積割合が４０ｖｏｌ％の塗膜の構造を示す
電子顕微鏡写真（×１０００）である。However, when the content is less than 50 vol%, water glass as a binder exists between the particles, and the average value of both materials of the particles and the water glass becomes the thermal expansion coefficient of the coating film. In addition, cracks may occur between the particles and the binder due to the difference in the coefficient of thermal expansion between the two materials.
FIG. 2 shows a coating film in which the volume ratio of Fe 2 O 3 powder particles is 50 vol% when the coating film is 100 vol%.
1 schematically shows a structure observed by an electron microscope.
As shown in FIG. 2, in this coating film, the voids between the coarse powder particles 10 having a relatively large particle diameter are filled with the fine powder particles 12 having a small particle diameter, so that the volume ratio of the powder particles is high. And a binder 14 is disposed therebetween. The black islands are the pores 16. As can be understood from FIG. 2, in the coating film, interparticle bonding occurs, and as described above, the thermal expansion coefficient of the Fe 2 O 3 powder particles is substantially regarded as the thermal expansion coefficient of the coating film. Can be. FIG. 4 shows Fe 2 O 3
It is an electron micrograph (x1000) which shows the structure of the coating film in which the volume ratio of a powder particle is 40 vol%.
【００２７】以上の結果より、塗膜における骨材（セラ
ミックス粉末）の体積割合は、固化後で５０ｖｏｌ％以
上必要である。なお、塗膜における骨材の体積割合の上
限は、一般的には、スラリー法による圧密度の限界であ
る７０ｖｏｌ％である。From the above results, it was found that the aggregate in the coating film (Cera)
The volume ratio of the mix powder) needs 5 0 vol% or more after solidification. In addition, the upper limit of the volume ratio of the aggregate in the coating film is generally 70 vol%, which is the limit of the compaction density by the slurry method.
【００２８】[0028]
【表２】 [Table 2]
【００２９】〔試験例３〕試験例１と同様な手順で鋳鉄
テストピースに塗膜を形成した。その際、膜厚だけを変
化させたものを作製した。このテストピースの塗膜の性
能を冷熱サイクルによる耐久性試験により調査した。耐
久性試験は、７００℃となる様に２０〜３０秒間バーナ
で塗膜付近を加熱した後、常温域の水中にて冷却するサ
イクルを１サイクルとし、剥離が生じるまでのサイクル
数を測定して行った。その結果を表３に示す。Test Example 3 A coating film was formed on a cast iron test piece in the same procedure as in Test Example 1. At that time, a device in which only the film thickness was changed was manufactured. The performance of the coating film of this test piece was investigated by a durability test by a cooling cycle. In the durability test, after heating the vicinity of the coating film with a burner for 20 to 30 seconds so as to be 700 ° C., the cycle of cooling in water in a normal temperature range is one cycle, and the number of cycles until peeling is measured. went. Table 3 shows the results.
【００３０】[0030]
【表３】 [Table 3]
【００３１】表３に示す様に、塗膜の膜厚が増加すると
耐久性が劣化する傾向にあることがわかる。表３から理
解できる様に、実施例１で用いたＦｅ2 Ｏ3 粉末粒子を
用いた塗膜では、目標とする５００サイクルは、５００
μｍの膜厚まで耐え得ることがわかる。また、表３のＮ
ｏ．９〜Ｎｏ．１１に示す様に、骨材を構成するセラミ
ックス粉末としてＺｒＯ2 粉末、Ａｌ2 Ｏ3 粉末、鋳鉄
粉を用いた膜厚５００μｍの比較例についても、同様に
試験した。その結果も表３に示す。As shown in Table 3, when the thickness of the coating film increases, the durability tends to deteriorate. As can be understood from Table 3, in the coating film using the Fe 2 O 3 powder particles used in Example 1, the target 500 cycles were 500 cycles.
It can be seen that the film can withstand a film thickness of μm. In Table 3, N
o. 9-No. As shown in FIG. 11, the same test was performed on a comparative example having a film thickness of 500 μm using ZrO 2 powder, Al 2 O 3 powder, and cast iron powder as ceramic powder constituting the aggregate. Table 3 also shows the results.
【００３２】表３に示す様に、骨材としてＦｅ2 Ｏ3 の
粉末粒子を用いた膜厚５００μｍのＮｏ．４は、上記比
較例に比較して著しく耐久性が向上していることがわか
る。これは、前述したように塗膜の熱膨張率と母材の熱
膨張率とがマッチングしている為と考える。しかし、比
較例である鋳鉄粉を用いたＮｏ．１１では、熱膨張率が
母材鋳鉄と同様であるはずなのに、高耐久性を示してい
ない。これは骨材である鋳鉄粉が高温にて酸化して熱膨
張したために塗膜内に亀裂を発生させたことが原因と考
えられる。As shown in Table 3, No. 2 powder having a thickness of 500 μm was prepared using powder particles of Fe 2 O 3 as an aggregate. 4 shows that the durability is remarkably improved as compared with the comparative example. This is considered to be because the coefficient of thermal expansion of the coating film and the coefficient of thermal expansion of the base material match as described above. However, in Comparative Example No. 3 using cast iron powder. In No. 11, although the coefficient of thermal expansion should be similar to that of the base cast iron, it does not show high durability. This is considered to be due to the fact that the cast iron powder as an aggregate was oxidized at a high temperature and thermally expanded, thereby causing cracks in the coating film.
【００３３】（他の例）上記した試験例１では、骨材重
量を１００ｗｔ％としたとき、５ｗｔ％の割合で分散剤
が添加されているが、これに限らず、適宜増減でき、例
えば５〜１０ｗｔ％にできる。また分散剤はポリカルボ
ン酸基をもつものが採用されているが、これに限らず、
公知のものを採用でき、例えば、ナフタレンスルホン酸
基をもつものでも良い。上記した試験例では無機バイン
ダーは水ガラスが採用されているが、これに限らず、ケ
イ酸ナトリウム、ケイ酸カリウム、ケイ酸リチウム等の
ケイ酸塩、第１リン酸アルミニウム、第１リン酸カリウ
ム、第１リン酸マグネシウム等のリン酸塩、コロイダル
シリカ等を採用しても良い。(Other Examples) In Test Example 1 described above, the dispersant was added at a ratio of 5 wt% when the weight of the aggregate was 100 wt%. However, the present invention is not limited to this. To 10 wt%. Also, a dispersant having a polycarboxylic acid group is employed, but is not limited thereto.
Known ones can be employed, for example, those having a naphthalenesulfonic acid group may be used. In the above-described test examples, water glass is used as the inorganic binder, but the inorganic binder is not limited thereto, and silicates such as sodium silicate, potassium silicate, and lithium silicate, monobasic aluminum phosphate, and monobasic potassium phosphate are used. Alternatively, a phosphate such as monobasic magnesium phosphate, colloidal silica, or the like may be used.
【００３４】[0034]
【発明の効果】本発明の断熱性を有する塗膜によれば、
金属母材に熱膨張率を近づけ得、耐剥離性を高め得る。According to the heat-insulating coating film of the present invention,
The coefficient of thermal expansion can be made closer to the metal base material, and the peel resistance can be increased.
【図１】スラリー中の粉末粒子含有率と固化後の塗膜に
おける粉末粒子含有率との関係を示すグラフである。FIG. 1 is a graph showing the relationship between the content of powder particles in a slurry and the content of powder particles in a coating film after solidification.
【図２】粉末粒子の体積割合が５０ｖｏｌ％の塗膜の組
織の粒子構造を電子顕微鏡で観察した状態を模式的に示
す組織図である。FIG. 2 is a structure diagram schematically showing a state where a particle structure of a structure of a coating film in which a volume ratio of powder particles is 50 vol% is observed with an electron microscope.
【図３】従来のベンガラ塗料で形成した塗膜の組織の粒
子構造を電子顕微鏡で観察した組織図である。FIG. 3 is a micrograph showing the particle structure of the microstructure of a coating film formed with a conventional red iron oxide paint, observed with an electron microscope.
【図４】粉末粒子の体積割合が５０ｖｏｌ％の塗膜の組
織の粒子構造を電子顕微鏡で観察した状態を示す写真図
である。FIG. 4 is a photograph showing a state in which the particle structure of the structure of a coating film in which the volume ratio of powder particles is 50 vol% is observed by an electron microscope.
図中、１０は粗粉末粒子、１２は微粉末粒子、１４はバ
インダー、１６は気孔を示す。In the figure, 10 indicates coarse powder particles, 12 indicates fine powder particles, 14 indicates a binder, and 16 indicates pores.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) C09D 5/00 C09D 1/00 - 1/12 ──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. 7 , DB name) C09D 5/00 C09D 1/00-1/12
Claims (1)
くとも１種からなる酸化鉄の粉末粒子を主要成分とする
セラミックス粉末と、残部が無機バインダーとで構成さ
れた高温域で使用される塗膜であり、 該塗膜の体積を１００ｖｏｌ％としたとき、塗膜におけ
る粒子間接合性を高めるように該セラミックス粉末粒子
は５０ｖｏｌ％以上に設定されており、 該セラミックス粉末粒子を１００ｖｏｌ％としたとき、
前記酸化鉄は２０ｖｏｌ％以上に設定されており、 ２０〜８００℃における熱膨張率は１１．５×１０-6〜
１６．５×１０-6に設定されていることを特徴とする断
熱性をもつ塗膜。A ceramic powder mainly composed of iron oxide powder particles of at least one of FeO, Fe 2 O 3 and Fe 3 O 4 , and the remainder being used in a high temperature region composed of an inorganic binder. When the volume of the coating film is 100 vol%, the ceramic powder particles are set at 50 vol% or more so as to enhance the interparticle bonding in the coating film. And when
The iron oxide is set to 20 vol% or more, and the coefficient of thermal expansion at 20 to 800 ° C. is 11.5 × 10 −6 to
A heat-insulating coating film characterized by being set to 16.5 × 10 −6 .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32243892A JP3178628B2 (en) | 1992-11-06 | 1992-11-06 | Insulating coating film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32243892A JP3178628B2 (en) | 1992-11-06 | 1992-11-06 | Insulating coating film |
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| Publication Number | Publication Date |
|---|---|
| JPH06145561A JPH06145561A (en) | 1994-05-24 |
| JP3178628B2 true JP3178628B2 (en) | 2001-06-25 |
Family
ID=18143678
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|---|---|---|---|
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| Country | Link |
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| DE19738622C2 (en) | 1997-09-04 | 2003-06-12 | Daimler Chrysler Ag | Exhaust pipe for a catalyst having exhaust system of an internal combustion engine |
| US6060154A (en) * | 1997-09-30 | 2000-05-09 | Sumitomo Metal Mining Co., Ltd. | Coating liquid for selective permeable membrane, selective permeable membrane and selective permeable multilayered membrane |
| JP2015063945A (en) | 2013-09-25 | 2015-04-09 | トヨタ自動車株式会社 | Seal structure for turbocharger |
| JP6467258B2 (en) * | 2015-03-20 | 2019-02-06 | 日本碍子株式会社 | Bonded body, honeycomb structure, and manufacturing method of bonded body |
| JP6814337B2 (en) * | 2016-10-07 | 2021-01-20 | 日産自動車株式会社 | A member for an internal combustion engine having a heat shield film, and a method for manufacturing the member. |
-
1992
- 1992-11-06 JP JP32243892A patent/JP3178628B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06145561A (en) | 1994-05-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |