JP4150954B2

JP4150954B2 - Metal-impregnated carbon sliding material and manufacturing method thereof

Info

Publication number: JP4150954B2
Application number: JP2002143151A
Authority: JP
Inventors: 浩一上田; 和己小鍜治
Original assignee: Hitachi Chemical Co Ltd; Showa Denko Materials Co Ltd
Current assignee: Showa Denko Materials Co Ltd
Priority date: 2002-05-17
Filing date: 2002-05-17
Publication date: 2008-09-17
Anticipated expiration: 2022-05-17
Also published as: JP2003328057A

Description

【０００１】
【発明の属する技術分野】
本発明は、各種ポンプや圧縮機などの軸受及びシール、真空ポンプのベーン等に使用される金属含浸カーボン摺動材料に関する。
【０００２】
【従来の技術】
従来の金属含浸カーボン摺動材は、例えば（石川敏功、長沖通）著、近代編集社発行の「新炭素工業」などに示されるように、人造黒鉛、天然黒鉛、カーボンブラック、コークス等の骨材の一種以上と、タールピッチ、コールタール等の結合剤の一種以上を適宜配合し、これらを混練機に投入し、１５０〜３００℃の温度で混練する。次にこの混練物を室温まで冷却した後、平均粒径１０〜３００μｍに粉砕し、次いで５０〜２００ＭＰａの圧力で成形、８００〜３０００℃の非酸化雰囲気中で焼成または必要に応じて黒鉛化し、さらにこの焼成品または黒鉛化品に鉛、銅などの金属を含浸する。特に、鉛は低融点金属であり含浸作業が容易であるばかりでなく、摩擦係数を下げ、摩耗量を減少させ、さらに耐焼付性を向上させるため、水中ポンプなどの軸受として、鉛含浸カーボン摺動材が広く使用されている。鉛含浸カーボン摺動材の場合、温度４００〜５００℃、減圧真空度５ｔｏｒｒ以下の条件で鉛溶融槽に上記の焼成品または黒鉛化品を浸漬した後、窒素やアルゴンガス等の不活性ガスにより０．４９〜０．９８ＭＰａまで加圧して、カーボン基材が有する気孔に鉛を含浸させる。この後、鉛溶融槽から引き上げて冷却した後、大気圧に戻して含浸を完了し、鉛含浸カーボン摺動材としている。この鉛含浸カーボン摺動材を機械加工して摺動材に供している。
【０００３】
しかしながら、重金属である鉛は環境汚染が心配され、廃棄品の市場からの回収が必要となるばかりでなく、鉛そのものの使用を制限あるいは廃止するようになってきている。
【０００４】
【発明が解決しようとする課題】
本発明は、鉛含浸カーボン摺動材と同等の摺動特性を有する、鉛を含まない金属含浸カーボン摺動材を提供するものである。
【０００５】
【課題を解決するための手段】
本発明は、学振法による黒鉛の格子定数測定法より求めた格子定数Ｃｏ＝０．６７２ｎｍ〜０．６８５ｎｍのカーボン基材にＺｎが９０〜９８重量％、Ａｌが２〜１０重量％の比率の金属を２０〜６５重量％含浸した金属含浸カーボン摺動材。
【０００６】
【発明の実施の形態】
本発明になる金属含浸カーボン軸受材は、鉛に替わる含浸金属として、Ｚｎが９０〜９８重量％、Ａｌが２〜１０重量％の比率の金属を使用する。格子定数Ｃｏ＝０．６７２ｎｍよりも小さいカーボン基材では軟らかく耐荷重性の低下、摩耗量の増大を引き起こす。また格子定数Ｃｏ＝０．６８５ｎｍより大きいと十分な摩擦係数低減効果が得られず、耐摩耗性、摩擦特性、なじみ性などが損なわれる。また、金属の含浸量は２０重量％〜６５重量％が好ましく２０重量％よりも少ないと、カーボン基材の気孔を金属によって埋めることが出来ず、機械的強度の低下、摺動特性の効果が十分でなく摩耗量の増大を引き起こす。含浸率が６５重量％より多いとカーボン基材の潤滑効果が得られず、摩擦係数が大きくなり摩耗量も増加する。
【０００７】
本発明になる金属含浸カーボン軸受材を製造するための原料としては、平均粒径が２０μｍ程度の黒鉛粉、油煙等を骨材として使用し、結合剤としてタールピッチ、コールタール等が使用される。本発明になる金属含浸カーボン摺動材は、前記各原料を用い、加熱混練、粉砕、成形、焼成した後、金属含浸することにより製造する事ができる。
【０００８】
加熱混練は、双腕型ニーダー等を用いて、各原料を１５０℃〜３００℃、より好ましくは１８０℃〜２７０℃、さらに好ましくは２００℃〜２５０℃の温度で混練する。混練温度が高いと機械的強度が低下する傾向があり、低いと混練時間が長くなる傾向がある。尚、混練時間については、混練物の量、骨材、結合剤の配合割合により変化するので、その都度適宜選定する必要がある。
【０００９】
粉砕は、加熱混練で得られたものを、各種粉砕機を用いて、平均粒径が２０〜３００μｍ程度、より好ましくは２０〜２００μｍ、更に好ましくは２０〜１００μｍになるように粉砕することにより行われる。
但し、平均粒径は続く成形方法や、焼成または黒鉛化後に得られるカーボン基材の特性を考慮し、適宜選択することが可能である。
【００１０】
成形は、粉砕して得られた粉体を、ブロック状に金型プレス等の方法でふ形することにより行われる。
【００１１】
成形圧力は、５０〜２００ＭＰａが好ましく、６０〜１５０ＭＰａがより好ましく８０〜１３０ＭＰａがさらに好ましい。
成形圧が低いと機械的強度が低下する傾向があり、高いと焼成中に揮発分の散逸が抑制されて成形品に内部圧力が生じ、割れやすくなる傾向がある。
【００１２】
上記により得られた成形品を焼成する。焼成は、窒素又はアルゴン等の不活性ガスを用いた非酸化雰囲気下または成形品の周囲に炭素粉を詰めて還元雰囲気下で焼成する方法が取られる。焼成時の最高到達温度は８００℃〜１０００℃が好ましく、８５０〜１０００℃がより好ましく、９００〜１０００℃が更に好ましい。焼成は温度が８００℃よりも低い場合、炭素化が不十分で十分な摺動特性を得られにくく、１０００℃以上の場合、焼成炉が劣化しやすくなる。焼成時間は原料の配合割合や製品形状あるいは炉の能力などにより決められるものであり、本発明においては特に制限されるものではないが、生産性及び生産コストの点から出来るだけ短時間で終了することが良い。具体的には５時間〜１００時間が好ましく、１０時間〜４００時間がより好もしく、２０時間〜３５０時間が更に好ましい。
【００１３】
目標とするカーボン基材を得るには、得られた焼成品を更に１０００℃以上の高温で黒鉛化しても良い。
この場合の最高温度は１２００〜３０００℃が好ましく、１５００〜３０００℃がより好ましく、２５００〜３０００℃が更に好ましい。
【００１４】
このようにして得られた焼成品又は黒鉛化品を学振法による黒鉛の格子定数測定法より測定する。
【００１５】
金属含浸は、上記により得られた学振法による黒鉛の格子定数測定法より求めた格子定数Ｃｏ＝０．６７２ｎｍ〜０．６８５ｎｍのカーボン基材を金属含浸容器に入れ５ｔｏｒｒ以下に減圧減圧脱気後、Ｚｎが９０〜９８重量％、Ａｌが２〜１０重量％の比率の金属からなる合金溶湯中に浸漬して窒素ガスにより０．４９〜０．９８ＭＰａまで加圧することにより行われる。このようにして得られた金属含浸カーボン材を機械加工し、所望の形状の軸受、シール、ベーン等の製品形状にすることができる。
【００１６】
【実施例】
以下本発明の実施例を説明する。
（実施例１）
骨材として、平均粒径が２０μｍの自家製人造黒鉛粉５５重量％に、結合剤としてタールピッチ（川崎製鉄（株）製、商品名ＰＫＬ）４５重量％を配合し、双腕型ニーダーを用いて温度２５０℃で５時間加熱混練した。
【００１７】
この後上記の混練物を、平均粒径２５μｍに粉砕した。この粉砕粉を寸法が１５０×２５０×５０ｍｍの金型に入れ、成形圧力１００ＭＰａで成形した。得られた成形品を、還元雰囲気下で１０００℃まで４００時間かけて昇温した後冷却した。
【００１８】
この焼成品を金属含浸容器に入れ、３ｔｏｒｒに減圧脱気後、Ｚｎが９６重量％、Ａｌが４重量％からなる合金の溶湯中に浸漬して窒素ガスにより０．９８ＭＰａまで加圧した。
得られた金属含浸カーボン材の物理特性，格子定数，含浸率及び摩耗試験の結果を表１に示す。
【００１９】
【表１】

【００２０】
（実施例２）
骨材として、平均粒径が２０μｍの自家製人造黒鉛粉４０重量％に、天然黒鉛１０重量％（日本黒鉛（株）製、商品名ＣＢ１５０）並びに結合剤としてタールピッチ（川崎製鉄（株）製、商品名ＰＫＬ）５０重量％を配合し、双腕型ニーダーを用いて温度２５０℃で５時間加熱混練した。この後上記の混練物を、平均粒径２５μｍに粉砕した。この粉砕粉を寸法が１５０×２５０×５０ｍｍの金型に入れ、成形圧力１００ＭＰａで成形した。得られた成形品を、還元雰囲気下で１０００℃まで４００時間かけて昇温した後冷却した。
【００２１】
この焼成品を金属含浸容器に入れ、３ｔｏｒｒに減圧脱気後、Ｚｎが９６重量％、Ａｌが４重量％からなる
合金の溶湯中に浸漬して窒素ガスにより０．９８ＭＰａまで加圧した。
得られた金属含浸カーボン材の物理特性，格子定数，含浸率及び摩耗試験の結果を表１に示す。
【００２２】
（実施例３）
骨材として、平均粒径が２０μｍの自家製人造黒鉛粉７重量％に、平均粒径が２０μｍのピッチコークス５３重量％並びに結合剤としてタールピッチ（川崎製鉄（株）製、商品名ＰＫＬ）４０重量％を配合し、双腕型ニーダーを用いて温度２５０℃で５時間加熱混練した。
この後上記の混練物を、平均粒径２５μｍに粉砕した。この粉砕粉を寸法が１５０×２５０×５０ｍｍの金型に入れ、成形圧力１００ＭＰａで成形した。得られた成形品を、還元雰囲気下で１０００℃まで４００時間かけて昇温した後冷却した。得られた焼成品の開気孔率を水中置換法により測定した結果、この焼成品を金属含浸容器に入れ、３ｔｏｒｒに減圧脱気後、Ｚｎが９６重量％、Ａｌが４重量％からなる
合金の溶湯中に浸漬して窒素ガスにより０．９８ＭＰａまで加圧した。得られた金属含浸カーボン材の物理特性，格子定数，含浸率及び摩耗試験の結果を表１に示す。
【００２３】
（実施例４）
実施例１記載のカーボン基材を用い、これを金属含浸容器に入れ、３ｔｏｒｒに減圧脱気後、Ｚｎが９０重量％、Ａｌが１０重量％からなる合金の溶湯中に浸漬して窒素ガスにより０．９８ＭＰａまで加圧した。
得られた金属含浸カーボン材の物理特性，格子定数，含浸率及び摩耗試験の結果を表１に示す。
【００２４】
（実施例５）
実施例１記載のカーボン基材を用い、これを金属含浸容器に入れ、３ｔｏｒｒに減圧脱気後、Ｚｎが９８重量％、Ａｌが２重量％からなる合金の溶湯中に浸漬して窒素ガスにより０．９８ＭＰａまで加圧した。
得られた金属含浸カーボン材の物理特性，格子定数，含浸率及び摩耗試験の結果を表１に示す。
【００２５】
（比較例１）
実施例２で得られたカーボン基材さらに３０００℃で黒鉛化を行った。この黒鉛化品を金属含浸容器に入れ、３ｔｏｒｒに減圧脱気後、鉛溶湯中に浸漬して窒素ガスにより０．９８ＭＰａまで加圧した。
得られた金属含浸カーボン材の物理特性，格子定数，含浸率及び摩耗試験の結果を表１に示す。
【００２６】
（比較例２）
比較例１で得られたカーボン基材を用いて、これを金属含浸容器に入れ、３ｔｏｒｒに減圧脱気後、Ｚｎが８９重量％、Ａｌが１１重量％からなる合金の溶湯中に浸漬して窒素ガスにより０．９８ＭＰａまで加圧した。
得られた金属含浸カーボン材の物理特性，格子定数，含浸率及び摩耗試験の結果を表１に示す。
【００２７】
（比較例３）
骨材として、平均粒径が２０μｍの自家製人造黒鉛粉３重量％に、平均粒径が２０μｍのピッチコークス５７重量％並びに結合剤としてタールピッチ（川崎製鉄（株）製、商比較例１で得られたカーボン基材を用いて、これを品名ＰＫＬ）４０重量％を配合し、双腕型ニーダーを用いて温度２５０℃で５時間加熱混練した。
【００２８】
この後上記の混練物を、平均粒径２５μｍに粉砕した。この粉砕粉を寸法が１５０×２５０×５０ｍｍの金型に入れ、成形圧力１００ＭＰａで成形した。得られた成形品を、還元雰囲気下で１０００℃まで４００時間かけて昇温した後冷却した。実施例１記載のカーボン基材を用い、これを金属含浸容器に入れ、３ｔｏｒｒに減圧脱気後、Ｚｎが９９重量％、Ａｌが１重量％からなる合金の溶湯中に浸漬して窒素ガスにより０．９８ＭＰａまで加圧した。
【００２９】
得られた金属含浸カーボン材の物理特性，格子定数，含浸率及び摩耗試験の結果を表１に示す。
尚、水中摩耗試験は、８×１２×１８ｍｍの試験片（摺動面１２×１８ｍｍ）を水中で回転する外径寸法φ８５ｍｍの円板（材質ＳＵＳ３０４）上で摺動させて行なった。周速は１０ｍ／ｓ、面圧は０．９８ＭＰａとして１００時間試験を行ない、摩擦係数及び摩耗量を測定した。
表２に示されるように、実施例１〜５は、比較例２及び３に比べて摩擦係数が小さく、摩耗量も少なく、比較例１の鉛含浸カーボン軸受と同等の摺動特性が確認された。
【００３０】
【発明の効果】
本発明によれば、請求項１記載の金属含浸カーボン摺動材は鉛を含まず、鉛含浸カーボン摺動材と同等の摺動特性を有しており、工業的に極めて好適である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal-impregnated carbon sliding material used for bearings and seals of various pumps and compressors, vanes of vacuum pumps, and the like.
[0002]
[Prior art]
Conventional metal-impregnated carbon sliding materials are, for example, artificial graphite, natural graphite, carbon black, coke, etc., as shown in “New Carbon Industry” published by Toshinori Ishikawa and Nagaoki Tsutsumi One or more kinds of aggregates and one or more kinds of binders such as tar pitch and coal tar are appropriately blended, put into a kneader and kneaded at a temperature of 150 to 300 ° C. Next, after cooling this kneaded product to room temperature, it is pulverized to an average particle size of 10 to 300 μm, then molded at a pressure of 50 to 200 MPa, calcined in a non-oxidizing atmosphere at 800 to 3000 ° C. or graphitized as necessary. Further, the fired product or graphitized product is impregnated with a metal such as lead or copper. In particular, lead is a low melting point metal and is not only easy to impregnate, but also reduces the coefficient of friction, reduces wear, and further improves seizure resistance. The moving material is widely used. In the case of a lead-impregnated carbon sliding material, after immersing the above fired product or graphitized product in a lead melting tank under conditions of a temperature of 400 to 500 ° C. and a vacuum of 5 torr or less, an inert gas such as nitrogen or argon gas is used. Pressure is applied to 0.49 to 0.98 MPa, and the pores of the carbon base material are impregnated with lead. Then, after pulling up from the lead melting tank and cooling, it is returned to atmospheric pressure to complete the impregnation, and the lead-impregnated carbon sliding material is obtained. This lead-impregnated carbon sliding material is machined to provide a sliding material.
[0003]
However, lead, which is a heavy metal, is concerned about environmental pollution, and not only does it need to be recovered from the market for waste products, but also restricts or eliminates the use of lead itself.
[0004]
[Problems to be solved by the invention]
The present invention provides a lead-free metal-impregnated carbon sliding material having sliding characteristics equivalent to that of a lead-impregnated carbon sliding material.
[0005]
[Means for Solving the Problems]
In the present invention, the ratio of Zn to 90 to 98% by weight and Al to 2 to 10% by weight on a carbon base material having a lattice constant Co = 0.672 nm to 0.685 nm determined by a method of measuring the lattice constant of graphite by the Gakushin method. A metal-impregnated carbon sliding material impregnated with 20 to 65% by weight of the above metal.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The metal-impregnated carbon bearing material according to the present invention uses a metal having a ratio of 90 to 98% by weight of Zn and 2 to 10% by weight of Al as an impregnated metal replacing lead. A carbon substrate smaller than the lattice constant Co = 0.672 nm is soft and causes a decrease in load resistance and an increase in wear. On the other hand, if the lattice constant Co is larger than 0.685 nm, a sufficient friction coefficient reducing effect cannot be obtained, and wear resistance, friction characteristics, conformability, and the like are impaired. Further, the impregnation amount of the metal is preferably 20% by weight to 65% by weight, and if the amount is less than 20% by weight, the pores of the carbon base material cannot be filled with the metal, and the mechanical strength is reduced and the sliding characteristics are effective. It is not sufficient and causes an increase in wear. When the impregnation ratio is more than 65% by weight, the lubricating effect of the carbon base material cannot be obtained, the friction coefficient increases, and the wear amount also increases.
[0007]
As raw materials for producing the metal-impregnated carbon bearing material according to the present invention, graphite powder having an average particle size of about 20 μm, oily smoke or the like is used as an aggregate, and tar pitch, coal tar or the like is used as a binder. . The metal-impregnated carbon sliding material according to the present invention can be produced by impregnating a metal after heating and kneading, pulverizing, molding, and firing using the respective raw materials.
[0008]
In the heat kneading, each raw material is kneaded at a temperature of 150 ° C. to 300 ° C., more preferably 180 ° C. to 270 ° C., more preferably 200 ° C. to 250 ° C., using a double-arm kneader or the like. If the kneading temperature is high, the mechanical strength tends to decrease, and if it is low, the kneading time tends to be long. The kneading time varies depending on the amount of the kneaded product, the blending ratio of the aggregate, and the binder, and therefore needs to be appropriately selected each time.
[0009]
The pulverization is performed by pulverizing the material obtained by heating and kneading using various pulverizers so that the average particle size is about 20 to 300 μm, more preferably 20 to 200 μm, and still more preferably 20 to 100 μm. Is called.
However, the average particle size can be appropriately selected in consideration of the subsequent molding method and the characteristics of the carbon substrate obtained after firing or graphitization.
[0010]
Molding is performed by forming the powder obtained by pulverization into a block shape by a method such as a die press.
[0011]
The molding pressure is preferably 50 to 200 MPa, more preferably 60 to 150 MPa, and still more preferably 80 to 130 MPa.
If the molding pressure is low, the mechanical strength tends to decrease. If the molding pressure is high, dissipation of volatile components is suppressed during firing, and an internal pressure is generated in the molded product, which tends to break.
[0012]
The molded product obtained as described above is fired. Firing is performed in a non-oxidizing atmosphere using an inert gas such as nitrogen or argon, or in a reducing atmosphere by filling carbon powder around a molded product. The highest reached temperature during firing is preferably 800 ° C to 1000 ° C, more preferably 850 to 1000 ° C, and still more preferably 900 to 1000 ° C. When the temperature is lower than 800 ° C., the carbonization is insufficient and it is difficult to obtain sufficient sliding characteristics. When the temperature is 1000 ° C. or higher, the firing furnace is liable to deteriorate. The firing time is determined by the blending ratio of raw materials, product shape, furnace capacity, etc., and is not particularly limited in the present invention, but is completed in as short a time as possible in terms of productivity and production cost. That is good. Specifically, 5 hours to 100 hours are preferable, 10 hours to 400 hours are more preferable, and 20 hours to 350 hours are more preferable.
[0013]
In order to obtain a target carbon substrate, the obtained fired product may be further graphitized at a high temperature of 1000 ° C. or higher.
The maximum temperature in this case is preferably 1200 to 3000 ° C, more preferably 1500 to 3000 ° C, and still more preferably 2500 to 3000 ° C.
[0014]
The fired product or graphitized product thus obtained is measured by a graphite lattice constant measurement method by the Gakushin method.
[0015]
In the metal impregnation, a carbon substrate having a lattice constant Co = 0.672 nm to 0.685 nm obtained from the graphite lattice constant measurement method by the Gakushin method obtained as described above is placed in a metal impregnation container and degassed under reduced pressure to 5 torr or less. Then, it immerses in the molten alloy which consists of a metal with a ratio of 90 to 98% by weight of Zn and 2 to 10% by weight of Al and pressurizes with nitrogen gas to 0.49 to 0.98 MPa. The metal-impregnated carbon material thus obtained can be machined into a product shape such as a bearing, seal or vane having a desired shape.
[0016]
【Example】
Examples of the present invention will be described below.
(Example 1)
As aggregate, 55% by weight of homemade artificial graphite powder having an average particle size of 20 μm and 45% by weight of tar pitch (made by Kawasaki Steel Co., Ltd., trade name PKL) as a binder are blended, and a double-arm kneader is used. Heat kneading was performed at a temperature of 250 ° C. for 5 hours.
[0017]
Thereafter, the kneaded product was pulverized to an average particle size of 25 μm. This pulverized powder was put into a mold having a size of 150 × 250 × 50 mm and molded at a molding pressure of 100 MPa. The obtained molded product was heated to 1000 ° C. over 400 hours in a reducing atmosphere and then cooled.
[0018]
This fired product was put in a metal impregnated container, degassed under reduced pressure to 3 torr, immersed in a molten alloy of 96 wt% Zn and 4 wt% Al, and pressurized to 0.98 MPa with nitrogen gas.
Table 1 shows the physical properties, lattice constant, impregnation rate, and wear test results of the resulting metal-impregnated carbon material.
[0019]
[Table 1]

[0020]
(Example 2)
As aggregate, 40% by weight of homemade artificial graphite powder having an average particle diameter of 20 μm, 10% by weight of natural graphite (product name: CB150, manufactured by Nippon Graphite Co., Ltd.) and tarpitch (made by Kawasaki Steel Co., Ltd.) as a binder, (Trade name PKL) 50% by weight was blended and heated and kneaded at a temperature of 250 ° C. for 5 hours using a double-arm kneader. Thereafter, the kneaded product was pulverized to an average particle size of 25 μm. This pulverized powder was put into a mold having a size of 150 × 250 × 50 mm and molded at a molding pressure of 100 MPa. The obtained molded product was heated to 1000 ° C. over 400 hours in a reducing atmosphere and then cooled.
[0021]
This fired product was put in a metal impregnated container, degassed under reduced pressure to 3 torr, immersed in a molten alloy of 96 wt% Zn and 4 wt% Al, and pressurized to 0.98 MPa with nitrogen gas.
Table 1 shows the physical properties, lattice constant, impregnation rate, and wear test results of the resulting metal-impregnated carbon material.
[0022]
(Example 3)
As aggregate, 7% by weight of homemade artificial graphite powder with an average particle size of 20 μm, 53% by weight of pitch coke with an average particle size of 20 μm, and 40% by weight of tar pitch (manufactured by Kawasaki Steel Co., Ltd., trade name PKL) %, And kneaded by heating at a temperature of 250 ° C. for 5 hours using a double-arm kneader.
Thereafter, the kneaded product was pulverized to an average particle size of 25 μm. This pulverized powder was put into a mold having a size of 150 × 250 × 50 mm and molded at a molding pressure of 100 MPa. The obtained molded product was heated to 1000 ° C. over 400 hours in a reducing atmosphere and then cooled. As a result of measuring the open porosity of the obtained fired product by an underwater substitution method, the fired product was put into a metal-impregnated container, and after degassing at 3 torr under reduced pressure, Zn was 96% by weight and Al was 4% by weight. It was immersed in the molten metal and pressurized to 0.98 MPa with nitrogen gas. Table 1 shows the physical properties, lattice constant, impregnation rate, and wear test results of the resulting metal-impregnated carbon material.
[0023]
Example 4
Using the carbon base material described in Example 1, this was placed in a metal impregnation vessel, degassed under reduced pressure to 3 torr, then immersed in a molten alloy of 90 wt% Zn and 10 wt% Al, and nitrogen gas was used. The pressure was increased to 0.98 MPa.
Table 1 shows the physical properties, lattice constant, impregnation rate, and wear test results of the resulting metal-impregnated carbon material.
[0024]
(Example 5)
Using the carbon base material described in Example 1, this was put in a metal impregnation vessel, vacuum degassed to 3 torr, immersed in a molten alloy of 98 wt% Zn and 2 wt% Al, and nitrogen gas was used. The pressure was increased to 0.98 MPa.
Table 1 shows the physical properties, lattice constant, impregnation rate, and wear test results of the resulting metal-impregnated carbon material.
[0025]
(Comparative Example 1)
The carbon base material obtained in Example 2 was further graphitized at 3000 ° C. This graphitized product was put in a metal-impregnated container, degassed under reduced pressure at 3 torr, immersed in molten lead, and pressurized to 0.98 MPa with nitrogen gas.
Table 1 shows the physical properties, lattice constant, impregnation rate, and wear test results of the resulting metal-impregnated carbon material.
[0026]
(Comparative Example 2)
Using the carbon base material obtained in Comparative Example 1, this was placed in a metal impregnation vessel, degassed to 3 torr under reduced pressure, and then immersed in a molten alloy of 89 wt% Zn and 11 wt% Al. The pressure was increased to 0.98 MPa with nitrogen gas.
Table 1 shows the physical properties, lattice constant, impregnation rate, and wear test results of the resulting metal-impregnated carbon material.
[0027]
(Comparative Example 3)
As an aggregate, 3% by weight of homemade artificial graphite powder having an average particle size of 20 μm, 57% by weight of pitch coke having an average particle size of 20 μm, and tar pitch (manufactured by Kawasaki Steel Corporation, commercial comparison example 1) as a binder Using the obtained carbon base material, 40 wt% of the product name PKL) was blended and heated and kneaded at a temperature of 250 ° C. for 5 hours using a double-arm kneader.
[0028]
Thereafter, the kneaded product was pulverized to an average particle size of 25 μm. This pulverized powder was put into a mold having a size of 150 × 250 × 50 mm and molded at a molding pressure of 100 MPa. The obtained molded product was heated to 1000 ° C. over 400 hours in a reducing atmosphere and then cooled. Using the carbon base material described in Example 1, this was put in a metal impregnation vessel, degassed under reduced pressure to 3 torr, immersed in a molten alloy of 99 wt% Zn and 1 wt% Al, and nitrogen gas was used. The pressure was increased to 0.98 MPa.
[0029]
Table 1 shows the physical characteristics, lattice constant, impregnation rate, and wear test results of the resulting metal-impregnated carbon material.
The underwater wear test was performed by sliding an 8 × 12 × 18 mm test piece (sliding surface 12 × 18 mm) on a disk (material SUS304) having an outer diameter of φ85 mm that rotates in water. The peripheral speed was 10 m / s, the surface pressure was 0.98 MPa, the test was conducted for 100 hours, and the friction coefficient and the wear amount were measured.
As shown in Table 2, Examples 1 to 5 have a smaller coefficient of friction and a smaller amount of wear than Comparative Examples 2 and 3, and the sliding characteristics equivalent to the lead-impregnated carbon bearing of Comparative Example 1 were confirmed. It was.
[0030]
【The invention's effect】
According to the present invention, the metal-impregnated carbon sliding material according to claim 1 does not contain lead, has sliding properties equivalent to the lead-impregnated carbon sliding material, and is extremely suitable industrially.

Claims

A carbon base material having a lattice constant Co = 0.672 nm to 0.685 nm obtained by a method of measuring the lattice constant of graphite by the Gakushin method, a metal having a ratio of 90 to 98 wt% Zn and 2 to 10 wt% Al is 20%. Metal impregnated carbon sliding material impregnated with ~ 65% by weight.