JPH07100787B2 - Ceramic coated metal gasket and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic coated metal gasket and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally used gaskets have been mainly made of asbestos molded products, but in recent years it has become difficult to use due to the problem of carcinogenicity.

As an alternative to this, the use of graphite gaskets, metal gaskets, etc. has increased, but since the main component of graphite gaskets is graphite, there is the problem that they are oxidized at high temperatures to CO ₂ and sublime.

Further, the metal gasket, which is made of ordinary iron, stainless steel, aluminum, copper or the like, has a drawback that it is oxidized at a high temperature and deteriorates to lose the gas sealing property. By using a heat resistant metal, deterioration at high temperature can be prevented, but in this case also, there is a drawback that the joint portion of the gasket is fused to the metal at high temperature and cannot be removed.

[0005]

In view of the problems of the prior art as described above, the present inventor has excellent heat resistance, metal fusion preventing property, lubricity, gas sealing property, etc., and uses it in a high temperature environment. We have earnestly studied to obtain a heat resistant gasket suitable for. As a result, they have found that the above object can be achieved by providing a ceramic layer by the sol-gel method on the surface of the metal gasket, and have completed the present invention.

That is, the present invention provides the following ceramic-coated metal gasket and a method for producing the same.

A ceramic-coated metal gasket comprising a ceramic layer formed by a sol-gel method on at least the surface of the metal gasket.

A method for producing a ceramic-coated metal gasket, which comprises applying a liquid composition of a ceramic raw material to at least a surface portion of the metal gasket and forming a ceramic layer by a sol-gel method.

The present invention is not particularly limited as long as it is a gasket made of metal and can be applied to various gaskets. The shape of the metal material is not particularly limited, and various types of molded products such as metal plates and rings can be targeted. The types of metal gaskets include, for example, corrugated metal plate gaskets, grooved metal gaskets, flat metal gaskets, serrated gaskets, lens rings, Bridgeman gaskets, delta gaskets, double cone gaskets, blind metal ring gaskets, Metal hollow O
There are rings, ring joint gaskets, etc., and examples of places used include chemical plant flanges, power plant steam flanges, oil refinery plant flanges, internal combustion engine (cylinder heads, exhaust manifolds, turbochargers, mufflers, etc.) flanges, autoclaves. There are bonnets, heat exchanger bonnets, etc. A particularly preferable object of application of the metal gasket of the present invention is a gasket for an internal combustion engine which is required to have heat resistance and lubricity.

The metal forming the gasket is not particularly limited, but it is determined according to the temperature usually used, and various metals or alloys such as iron, aluminum, copper, stainless steel and titanium can be used. It is also possible to use a material plated with zinc, nickel, chrome or any other metal or alloy.

In the present invention, a ceramic layer formed by the sol-gel method is provided on the surface of the metal forming the gasket. The ceramic layer by the sol-gel method is a dense film,
Excellent adhesion and good thermal shock resistance. Various methods are known as a method for forming a ceramic layer by the sol-gel method, and various raw materials are known, but the present invention is not particularly limited, and any method can be adopted.

Ceramics by the sol-gel method can be usually formed by applying a liquid composition of a ceramic raw material, polymerizing and gelling. The liquid composition contains various metal alkoxides and metal hydroxides as a ceramic raw material. As a preferable example of such a ceramic raw material, a) the formula (R ₁ ) mM ₁ (OR ₂ ) n (the formula Wherein R ₁ is an alkyl group having 1 to 3 carbon atoms or a vinyl group, R ₂ is hydrogen, methyl, ethyl, isopropyl or t
-Butyl, M ₁ is Ca or Ba, m is 0 or 1, n is 1
Or a compound represented by 2) b) Formula (R ₃ ) kM ₂ (OR ₄ ) l (In the formula, R ₃ is an alkyl group having 1 to ₃ carbon atoms or a vinyl group, R ₄ is hydrogen, methyl, Ethyl, isopropyl or t
-Butyl, M ₂ is Al, Y or La, k is 0 or 1, l
Is a compound represented by 2 or 3) c) Formula (R ₅ ) iM ₃ (OR ₆ ) j (in the formula, R ₅ is an alkyl group or vinyl group having 1 to 3 carbon atoms, R ₆ is hydrogen, Methyl, ethyl, isopropyl or t
- butyl, _{M 3} is Ti, Zr, Mn, Sn, Si or S
r and i are 0 or 1, j is 3 or 4, and the like. These compounds are 1
They may be used either alone or in combination of two or more.
You may use what condensed the seed | species or more.

Specific examples of the above ceramic raw materials include:
_{Ca (OCH 3) 2, Ca} (OC 2 H 5) 2, Ca (O
_{C 3 H 7) 2, Ca} (OC 4 H 9) 2, Ba (OC
_{H 3) 2, Ba (OC} 2 H 5) 2, Ba (OC 3 H 7)
₂ , Ba (OC ₄ H ₉ ) ₂ , Al (OCH ₃ ) ₃ , Al
(OC ₂ H ₅ ) ₃ , Al (OC ₃ H ₇ ) ₃ , Al (OC
₄ H ₉ ) ₃ , CH ₃ Al (OCH ₃ ) ₂ , CH ₃ Al
(OC ₂ H ₅ ) ₂ , CH ₃ Al (OC ₃ H ₇ ) ₂ , CH
₃ Al (OC ₄ H ₉ ) ₂ , Ti (OCH ₃ ) ₄ , Ti
(OC ₂ H ₅ ) ₄ , Ti (OC ₃ H ₇ ) ₄ , Ti (OC
₄ H ₉ ) ₄ , CH ₃ Ti (OCH ₃ ) ₃ , CH ₃ Ti
(OC ₂ H ₅ ) ₃ , CH ₃ Ti (OC ₃ H ₇ ) ₃ , CH
₃ Ti (OC ₄ H ₉ ) ₃ , C ₂ H ₅ Ti (OC
_{H 3) 3, C 2 H} 5 Ti (OC 2 H 5) 3, C 2 H 5 T
i (OC ₃ H ₇ ) ₃ , C ₂ H ₅ Ti (OC ₄ H ₉ ) ₃ ,
Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (O
_{C 3 H 7) 4, Si} (OC 4 H 9) 4, CH 3 Si (O
_{CH 3) 3, CH 3 Si} (OC 2 H 5) 3, CH 3 Si
(OC ₃ H ₇ ) ₃ , CH ₃ Si (OC ₄ H ₉ ) ₃ , C _{2
H 5 Si (OCH 3) 3} , C 2 H 5 Si (OC 2 H 5)
₃ , C ₂ H ₅ Si (OC ₃ H ₇ ) ₃ , C ₂ H ₅ Si (O
_{C 4 H 9) 3, Zr} (OCH 3) 4, Zr (OC
₂ H ₅ ) ₄ , Zr (OC ₃ H ₇ ) ₄ , Zr (OC
₄ H ₉ ) ₄ , CH ₃ Zr (OCH ₃ ) ₃ , CH ₃ Zr
_{(OC 2 H 5) 3,} CH 3 Zr (OC 3 H 7) 3, CH
₃ Zr (OC ₄ H ₉ ) ₃ , C ₂ H ₅ Zr (OC
_{H 3) 3, C 2 H} 5 Zr (OC 2 H 5) 3, C 2 H 5 Z
r (OC ₃ H ₇ ) ₃ , C ₂ H ₅ Zr (OC ₄ H ₉ ) ₃ ,
Y (OCH ₃ ) ₃ , Y (OC ₂ H ₅ ) ₃ , Y (OC ₃ H
₇ ) ₃ , Y (OC ₄ H ₉ ) ₃ , La (OCH ₃ ) ₃ , L
a (OC ₂ H ₅ ) ₃ , La (OC ₃ H ₇ ) ₃ , La (O
_{C 4 H 9) 3, Mn} (OCH 3) 4, Mn (OC
₂ H ₅ ) ₄ , Mn (OC ₃ H ₇ ) ₄ , Mn (OC
_{4 H 9) 4, Sn (} OCH 3) 4, Sn (OC 2 H 5)
₄ , Sn (OC ₃ H ₇ ) ₄ , Sn (OC ₄ H ₉ ) ₄ , S
r (OCH ₃ ) ₄ , Sr (OC ₂ H ₅ ) ₄ , Sr (OC
₃ H ₇ ) ₄ , Sr (OC ₄ H ₉ ) ₄ , Ca (OH) ₂ ,
Ba (OH) ₂ , Al (OH) ₃ , CH ₃ Al (OH)
₂ , Ti (OH) ₄ , CH ₃ Ti (OH) ₃ , C ₂ H ₅
Ti (OH) ₃ , Si (OH) ₄ , CH ₃ Si (OH)
₃ , C ₂ H ₅ Si (OH) ₃ , Zr (OH) ₄ , CH ₃
Zr (OH) ₃ , C ₂ H ₅ Zr (OH) ₃ , Y (OH)
₃ , La (OH) ₃ , Mn (OH) ₄ , Sn (O
H) ₄ , Sr (OH) _{4 and the} like can be mentioned. Further, these condensates can be freely prepared by arbitrarily combining the above compounds, and the molecular weight can be appropriately selected. Examples of the condensate include ZrOSi (OC ₂ H ₅ ) ₆ and Al.
OSi (OC ₂ H ₅ ) ₅ , TiOSi (OC
₂ H ₅ ) ₆ , (C ₃ H ₇ O) ₃ ZrOSi (OC
₂ H ₅ ) ₃ , (C ₄ H ₉ O) ₃ ZrOSi (OC
_{2 H 5) 3, (C} 3 H 7 O) 3 TiOSi (OC
₂ H ₅ ) ₃ , (C ₄ H ₉ O) ₃ TiOSi (OC
₂ H ₅ ) ₃ , (C ₃ H ₇ O) ₂ AlOSi (OC
₂ H ₅ ) ₃ , (C ₄ H ₉ O) ₂ AlOSi (OC
₂ H ₅ ) ₃ , etc.

These ceramic raw materials are usually dissolved or dispersed in an organic solvent, water, a mixed solvent thereof, or the like, but the ceramic raw materials themselves may be used as they are. As the organic solvent, any of those used in the liquid composition of the known sol-gel method can be used, and for example, lower alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether, propylene glycol. Hydrocarbon ether alcohols having methyl, ethyl, butyl and the like as an alkyl group such as monoalkyl ether and dipropylene glycol monoalkyl ether, ethylene glycol monoalkyl ether acetate, diethylene glycol monoalkyl ether acetate, propylene glycol monoalkyl ether acetate, di Acetic acid esters of the above hydrocarbon ether alcohols such as propylene glycol monoalkyl ether acetate , Alcohols acetic esters such as ethoxyethyl acetate, methyl acetate, ethyl acetate, propyl acetate, esters such as butyl acetate, can be used acetone.

The concentration of the ceramic raw material in the liquid composition may be usually about 10 to 100% by weight, and may be appropriately determined according to the properties of the raw material used.

If desired, a colloidal substance and / or an inorganic fine powder may be added to the liquid composition of the ceramic raw material. The ceramic layer formed by the sol-gel method is more densified by adding the colloidal substance and / or the inorganic fine powder.

The colloidal substance used in the present invention is
Liquid or solid particles of about 10 to 10000 angstrom are dispersed in a dispersion medium, and various known materials can be used. As the dispersion medium, usually, the above lower alcohols, hydrocarbon ether alcohols,
Organic solvents such as acetic acid esters and water are used alone or as a mixture, and the concentration of dispersed particles is generally about 10 to 60% by weight. In the present invention, any of these colloidal substances can be used. Specific examples of the colloidal substance include colloidal silica, colloidal alumina, colloidal titanium oxide, colloidal zirconium oxide, colloidal zirconium silicate, colloidal aluminum hydroxide, colloidal zirconium hydroxide and the like. .

As the inorganic fine powder, those having a particle diameter of about 5 to 150 mμ are suitable, and for example, alumina fine powder, titanium oxide fine powder, silica fine powder and the like can be used.

The colloidal substance and / or the inorganic fine powder are
It can be added up to about 70% by weight, preferably about 3 to 40% by weight, in the liquid composition of the ceramic raw material.

The liquid composition of the above ceramic raw material contains
Further, if necessary, a filler, a pigment, a coating reinforcing material, etc. may be added. As the filler and the pigment, it is possible to use a usual inorganic one, for example, magnesium oxide,
Silicon nitride, boron nitride, graphite, titanium nitride, nickel oxide, quartz, silica, zirconium silicate, alumina, titanium oxide, titanium yellow, magnesium carbonate, dolomite,
Silicon carbide, tungsten carbide, iron oxide (red, black), barium yellow, antimony yellow, cobalt blue,
Cobalt violet, cobalt green, manganese black, manganese blue, manganese violet, strontium chromate, talc, chromium oxide hydrate green, chromium oxide green, zinc green, barium carbonate, chalk, precipitated calcium carbonate, alumina hydrate, zinc oxide, firefly Stone, molybdenum red, molybdenum orange, chrome yellow, lead chromate, ultramarine, vermilion, basic lead carbonate and the like can be used. Of these, especially silicon nitride,
Boron nitride and the like can reduce the friction coefficient of the ceramics layer, and are advantageous because cracks are less likely to occur in the gasket due to improved slippage when thermal expansion occurs. The filler and pigment can be used together with a thickener and the like according to a conventional method.

The coating reinforcing material is an inorganic fibrous material, and typical examples thereof include potassium titanate, silicon carbide, silicon nitride, aluminum oxide, beryllia boron carbide, silicate glass, and quartz.

The filler and / or pigment may be added to the liquid composition in an amount of up to about 70% by weight, preferably about 0.1 to 10% by weight. The lining covering reinforcing material is contained in the liquid composition up to about 70% by weight, preferably 1 to 60% by weight.
It can be added to some extent.

The liquid composition described above is preferably adjusted to a pH of about 2.5 to 6.0 in order to prevent rapid gelation. For the pH adjustment, for example, an inorganic acid or an organic acid such as hydrochloric acid, acetic acid, chloroacetic acid, citric acid, maleic acid, oxalic acid, toluenesulfonic acid, glutaric acid, dimethylmalonic acid, benzoic acid can be used.

Further, the above liquid composition further comprises a buffered latent catalyst capable of accelerating the polymerization of the liquid composition by dissociating by heating without gelling the liquid composition at room temperature. , Carboxylic acid metal salts, amine carboxylates, quaternary ammonium carboxylates, nitrates and the like can be added to the liquid composition up to about 1.5% by weight. Examples of such a buffered latent catalyst include dimethylamine acetate, ethanolamine acetate, dimethylaniline formate, sodium acetate, sodium propionate, potassium formate, sodium formate, benzyltrimethylammonium acetate, sodium nitrate, ammonium nitrate and the like.

In the present invention, the above-mentioned liquid composition of the ceramic raw material is applied onto a metal gasket by various coating methods such as a spray method, a dip method, a roll coating method, a brush coating method and a printing method to form a polymer gel. By doing so, a ceramic layer is formed. The metal gasket usually has a structure in which two or more metal plates are laminated, but in this case, a ceramic layer may be formed on each metal plate constituting the gasket and then processed into a gasket, or Alternatively, the gasket may be manufactured in advance, and the liquid composition of the ceramic raw material may be applied to the surface portion of the gasket and polymerized to form the ceramic layer.

Polymerization gelation of the liquid composition of the ceramic raw material proceeds even at room temperature, but by heating, the gelation time is shortened, the polymerization density is increased, and the ceramic layer is more densified. The heating temperature is not particularly limited, and the higher the temperature is, the more dense the ceramic layer can be made. However, from the viewpoint of cost, it is suitable to heat at about 100 to 250 ° C. for about 10 to 30 minutes.

In the ceramic layer prepared by the sol-gel method, in order to completely prevent the generation of pinholes, after the liquid composition of the ceramic raw material is applied, dried, or cured by heating, one or more layers of the liquid composition are further added. It is preferable that two or more layers are overcoated and cured to form two or more ceramic layers.

When a filler and / or a pigment is added to the liquid composition of the ceramic raw material to be used,
A ceramic layer made of a liquid composition of a ceramic raw material to which a filler and a pigment are not added is provided on the formed ceramic layer to a thickness of about 0.5 to 10 μm to make the surface of the ceramic layer dense. The water repellency can be further improved.

The ceramic layer formed by the sol-gel method may have a total thickness of about 3 to 150 μm.

Since the ceramic layer thus formed has a high surface hardness, it is not easily scratched, and it is nonflammable. Therefore, it does not decompose or burn even when exposed to high temperatures. No harmful gas is generated. Further, it has excellent features such that oxidative deterioration of metal at high temperature can be prevented, fusion resistance can be prevented due to its high heat resistance, and the coefficient of friction hardly rises.

[0031]

The ceramic coated metal gasket of the present invention has excellent heat resistance and is resistant to oxidative deterioration.
It can prevent fusion of metal, has good lubricity, hardly cracks, has good gas sealability, and can retain its role as a gasket for a long time even when exposed to a high temperature environment. .

[0032]

The present invention will be described in more detail with reference to the following examples.

[0033]

Example 1 15 g of isopropyl alcohol and 15 water
1 g of fine powder alumina having a particle size of 20 mμ in a mixed solvent consisting of 1 g
3 g was added, and as a filler, 15 g of zirconium silicate, 10 g of manganese oxide, 15 g of silica and 10 g of boron nitride,
9 g of potassium titanate fiber was added as a coating reinforcing agent, and 30 g of methyltrimethoxysilane was added to and mixed with a solution containing 0.1 g of hydrochloric acid, to prepare a liquid composition of a ceramic raw material.

The above liquid composition was applied by a spray method to the entire surface of a metal gasket for an exhaust manifold having a three-layer laminated structure of an upper plate, a middle plate and a lower plate made of SUS304 stainless steel, and heated at 150 ° C. for 30 minutes. Then, a ceramic layer having a thickness of 20 μm was formed.

When the obtained ceramic-coated metal gasket was heated at 800 ° C. for 5 hours, no deterioration of the surface layer due to oxidation was observed, and the friction coefficient was 0.
What was 226 fell to 0.164. On the other hand, when a gasket made of SUS stainless steel having no ceramic layer was heated at 800 ° C. for 5 hours, the stainless steel was prone to oxidative deterioration, and the oxide film on the surface fell off to reduce the weight of the gasket.

When the above-mentioned ceramics-coated metal gasket was used between the cylinder head and the exhaust manifold of an internal combustion engine, good shielding performance could be maintained without oxidative deterioration even after long-term use. It was

[0037]

Example 2 Ti (OC ₄ H ₉ ) ₄ and Si (OC
₂ H _{5) 4} partial condensation products _{(C 4 H 9 O) 3} Ti-OSi
35 g of (OC ₂ H ₅ ) _{3 was} added with isopropyl alcohol 12
g and butyl cellosolve 3 g are added and mixed, and further 10 g of talc, 10 g of aluminum oxide and 20 g of graphite as a filler, 5 g of potassium titanate fiber as a coating reinforcing agent, and 0.5 g of acetic acid are further added to prepare a ceramic raw material. A liquid composition was prepared.

The above liquid composition was applied by a spray method on the entire surface of a cylinder head gasket of a four-cylinder engine having a three-layer laminated structure of an upper plate, a middle plate and a lower plate made of SUS304 stainless steel, and then at 200 ° C. It was heated for 20 minutes to form a ceramic layer having a thickness of 10 μm by the sol-gel method. By using the obtained ceramic coating gasket and attaching the cylinder head part to the engine body, when used, the gasket did not deteriorate due to oxidation, friction of the cylinder head due to engine vibration was prevented, and for a long period of time Airtightness was maintained well.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-46287 (JP, A) JP-A-55-131079 (JP, A) Actually-opened Shou 64-33181 (JP, U) Special table Sho-62- 501871 (JP, A)

Claims (2)

[Claims] 1. A ceramic-coated metal gasket having a ceramic layer formed by a sol-gel method on at least a surface portion of the metal gasket. 2. At least a surface portion of the metal gasket,
A method for producing a ceramic-coated metal gasket, which comprises applying a liquid composition of a ceramic raw material and forming a ceramic layer by a sol-gel method.