JP6258139B2 - Sliding member - Google Patents
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- JP6258139B2 JP6258139B2 JP2014140087A JP2014140087A JP6258139B2 JP 6258139 B2 JP6258139 B2 JP 6258139B2 JP 2014140087 A JP2014140087 A JP 2014140087A JP 2014140087 A JP2014140087 A JP 2014140087A JP 6258139 B2 JP6258139 B2 JP 6258139B2
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- 229910000658 steel phase Inorganic materials 0.000 claims description 260
- 239000010410 layer Substances 0.000 claims description 181
- 229910018104 Ni-P Inorganic materials 0.000 claims description 96
- 229910018536 Ni—P Inorganic materials 0.000 claims description 96
- 229910000905 alloy phase Inorganic materials 0.000 claims description 71
- 229910000859 α-Fe Inorganic materials 0.000 claims description 68
- 229910052751 metal Inorganic materials 0.000 claims description 61
- 239000002184 metal Substances 0.000 claims description 61
- 239000011342 resin composition Substances 0.000 claims description 49
- 229910000975 Carbon steel Inorganic materials 0.000 claims description 37
- 239000010962 carbon steel Substances 0.000 claims description 37
- 239000012791 sliding layer Substances 0.000 claims description 36
- 229910001567 cementite Inorganic materials 0.000 claims description 31
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 claims description 30
- 229910001562 pearlite Inorganic materials 0.000 claims description 28
- 239000000203 mixture Substances 0.000 claims description 25
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 17
- 229910052799 carbon Inorganic materials 0.000 claims description 16
- 239000002245 particle Substances 0.000 claims description 12
- 239000011148 porous material Substances 0.000 claims description 10
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- 239000012535 impurity Substances 0.000 claims description 7
- 239000012071 phase Substances 0.000 description 177
- 239000000843 powder Substances 0.000 description 55
- 229910045601 alloy Inorganic materials 0.000 description 30
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 25
- 238000005245 sintering Methods 0.000 description 25
- 125000004429 atom Chemical group 0.000 description 23
- 239000011135 tin Substances 0.000 description 16
- 229910000831 Steel Inorganic materials 0.000 description 15
- 239000010959 steel Substances 0.000 description 15
- 229910001566 austenite Inorganic materials 0.000 description 14
- 239000007791 liquid phase Substances 0.000 description 14
- 239000010949 copper Substances 0.000 description 13
- 239000011812 mixed powder Substances 0.000 description 13
- 230000007797 corrosion Effects 0.000 description 12
- 238000005260 corrosion Methods 0.000 description 12
- 239000000463 material Substances 0.000 description 12
- 229910052802 copper Inorganic materials 0.000 description 11
- 229910000881 Cu alloy Inorganic materials 0.000 description 9
- 238000003892 spreading Methods 0.000 description 9
- 229910052742 iron Inorganic materials 0.000 description 8
- 238000000034 method Methods 0.000 description 8
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- 239000000446 fuel Substances 0.000 description 7
- 229910052718 tin Inorganic materials 0.000 description 7
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 6
- 238000010586 diagram Methods 0.000 description 6
- 238000009792 diffusion process Methods 0.000 description 6
- 150000007524 organic acids Chemical class 0.000 description 6
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- 229910052717 sulfur Inorganic materials 0.000 description 6
- 239000011593 sulfur Substances 0.000 description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 5
- 229910052796 boron Inorganic materials 0.000 description 5
- 229910052804 chromium Inorganic materials 0.000 description 5
- 239000013078 crystal Substances 0.000 description 5
- 229910052759 nickel Inorganic materials 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- 230000009466 transformation Effects 0.000 description 5
- 239000011651 chromium Substances 0.000 description 4
- -1 polyethylene Polymers 0.000 description 4
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- 241000357293 Leptobrama muelleri Species 0.000 description 3
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- 229910000765 intermetallic Inorganic materials 0.000 description 3
- 238000005304 joining Methods 0.000 description 3
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- 239000004698 Polyethylene Substances 0.000 description 2
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- 229910052725 zinc Inorganic materials 0.000 description 2
- 229910052582 BN Inorganic materials 0.000 description 1
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 description 1
- 229910001208 Crucible steel Inorganic materials 0.000 description 1
- FBPFZTCFMRRESA-JGWLITMVSA-N D-glucitol Chemical compound OC[C@H](O)[C@@H](O)[C@H](O)[C@H](O)CO FBPFZTCFMRRESA-JGWLITMVSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 229910001096 P alloy Inorganic materials 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 239000004696 Poly ether ether ketone Substances 0.000 description 1
- 229930182556 Polyacetal Natural products 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 239000004962 Polyamide-imide Substances 0.000 description 1
- 239000004693 Polybenzimidazole Substances 0.000 description 1
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- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001879 copper Chemical class 0.000 description 1
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- 229910021389 graphene Inorganic materials 0.000 description 1
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- 238000004519 manufacturing process Methods 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
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- 239000000155 melt Substances 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- QLOAVXSYZAJECW-UHFFFAOYSA-N methane;molecular fluorine Chemical compound C.FF QLOAVXSYZAJECW-UHFFFAOYSA-N 0.000 description 1
- CWQXQMHSOZUFJS-UHFFFAOYSA-N molybdenum disulfide Chemical compound S=[Mo]=S CWQXQMHSOZUFJS-UHFFFAOYSA-N 0.000 description 1
- 229910052982 molybdenum disulfide Inorganic materials 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
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- 229920002647 polyamide Polymers 0.000 description 1
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- 229940098458 powder spray Drugs 0.000 description 1
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- 238000005507 spraying Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- ALRFTTOJSPMYSY-UHFFFAOYSA-N tin disulfide Chemical compound S=[Sn]=S ALRFTTOJSPMYSY-UHFFFAOYSA-N 0.000 description 1
Description
本発明は、耐食性及び耐摩耗性が高く、且つ、摺動層の樹脂組成物と多孔質焼結層との接合が強い摺動部材に関する。 The present invention relates to a sliding member having high corrosion resistance and wear resistance, and having strong bonding between a resin composition of a sliding layer and a porous sintered layer.
従来、燃料噴射ポンプ用の摺動部材には、５〜２５％程度の気孔率を有する焼結銅系材料が用いられている。この摺動部材は、摺動部材の内部に存在する気孔を介して、液体燃料を円筒形状の摺動部材の外周面側から内周面（摺動面）側に供給することにより、内周面（摺動面）に液体燃料の流体潤滑膜を形成し、高速回転する軸を支承するようになっている。このような焼結銅系材料は、燃料中に含まれる有機酸、硫黄成分による銅合金の腐食が起こり、この銅系腐食生成物が燃料に混入する問題がある。このため、耐食性を高めるためにＮｉ、Ａｌ、Ｚｎを含有させた焼結銅系摺動材料が提案されている（例えば、特許文献１〜３参照）。 Conventionally, a sintered copper-based material having a porosity of about 5 to 25% is used for a sliding member for a fuel injection pump. This sliding member supplies the liquid fuel from the outer peripheral surface side to the inner peripheral surface (sliding surface) side of the cylindrical sliding member through the pores existing inside the sliding member. A fluid lubricating film of liquid fuel is formed on the surface (sliding surface), and a shaft that rotates at high speed is supported. Such a sintered copper-based material has a problem that corrosion of a copper alloy occurs due to an organic acid and a sulfur component contained in the fuel, and this copper-based corrosion product is mixed into the fuel. For this reason, in order to improve corrosion resistance, the sintered copper-type sliding material containing Ni, Al, and Zn is proposed (for example, refer patent documents 1-3).
また、従来、鋼裏金の表面に銅めっき層を介して銅合金からなる多孔質焼結層を設け、更に、多孔質焼結層の空孔部および表面に樹脂組成物を含浸被覆した複層の摺動材料からなる摺動部材が用いられている（例えば、特許文献４、５参照）。そして、このような複層摺動材料を燃料噴射ポンプ用の摺動部材に適用したものが提案されている（例えば、特許文献６参照）。 Conventionally, a porous sintered layer made of a copper alloy has been provided on the surface of the steel back metal via a copper plating layer, and further, a multi-layer in which pores and surfaces of the porous sintered layer are impregnated and coated with a resin composition The sliding member which consists of these sliding materials is used (for example, refer patent document 4, 5). And what applied such a multilayer sliding material to the sliding member for fuel-injection pumps is proposed (for example, refer patent document 6).
ところで、特許文献１〜３の焼結銅系摺動材料は、Ｎｉ、Ａｌ、Ｚｎを含有させて耐食性を高めてはいるが、燃料中に含まれる有機酸、硫黄成分による銅合金の腐食を完全には防止できない。また、特許文献１〜３の焼結銅系摺動材料は、摺動部材の内部全体に気孔を形成するために強度が低く、特に特許文献６に示すようなコモンレール方式の燃料噴射ポンプ等に用いられる摺動部材としては負荷能力が不十分である。 By the way, although the sintered copper-type sliding material of patent documents 1-3 contains Ni, Al, and Zn and has improved corrosion resistance, corrosion of the copper alloy by the organic acid contained in fuel, and a sulfur component is carried out. It cannot be completely prevented. In addition, the sintered copper-based sliding material of Patent Documents 1 to 3 is low in strength to form pores in the entire inside of the sliding member, and is particularly suitable for a common rail fuel injection pump as shown in Patent Document 6 and the like. As the sliding member used, the load capacity is insufficient.
一方、特許文献４〜６の複層摺動材料では、鋼裏金の構成を有するので強度は高いが、銅合金からなる多孔質焼結層は、燃料あるいは潤滑油中に含まれる有機酸や硫黄成分で銅合金の腐食が起こる。また、特許文献４〜６の複層摺動材料では、摺動部材として使用中に、多孔質焼結層の表面に被覆した樹脂組成物が摩耗し、摺動面となる表面に銅合金からなる多孔質焼結層が露出する場合や、使用前に、予め複層摺動材料の表面に切削加工を施して、摺動面となる表面に銅合金からなる多孔質焼結層を露出させた状態とした後に摺動部材として使用する場合がある。しかしながら、特許文献４〜６の複層摺動材料は、銅合金からなる多孔質焼結層の強度が十分ではないため、良好な耐摩耗性を有さない。さらに、特許文献４〜６のような銅めっき層を鋼裏金の表面に設けることなく、単に炭素鋼の粉末を鋼裏金の表面に散布し焼結して多孔質焼結層を形成し、該多孔質焼結層に樹脂組成物を含浸、被覆した摺動材料は、摺動層の樹脂組成物と多孔質焼結層との界面での接合が弱くなることが判明した。 On the other hand, the multi-layer sliding materials of Patent Documents 4 to 6 have a steel backing metal structure, so that the strength is high. However, the porous sintered layer made of a copper alloy is made of an organic acid or sulfur contained in fuel or lubricating oil. Corrosion of the copper alloy occurs with the components. Moreover, in the multilayer sliding material of patent documents 4-6, the resin composition coat | covered on the surface of the porous sintered layer wears during use as a sliding member, and the surface used as a sliding surface is made from a copper alloy. When the porous sintered layer to be exposed is exposed or prior to use, the surface of the multilayer sliding material is preliminarily cut to expose the porous sintered layer made of a copper alloy on the surface to be the sliding surface. In some cases, it may be used as a sliding member after it has been brought into contact. However, the multi-layer sliding materials of Patent Documents 4 to 6 do not have good wear resistance because the strength of the porous sintered layer made of a copper alloy is not sufficient. Furthermore, without providing a copper plating layer as in Patent Documents 4 to 6 on the surface of the steel back metal, simply spraying and sintering carbon steel powder on the surface of the steel back metal to form a porous sintered layer, It has been found that the sliding material obtained by impregnating and coating the porous sintered layer with the resin composition has weak bonding at the interface between the resin composition of the sliding layer and the porous sintered layer.
本発明は、上記した事情に鑑みなされたものであり、その目的とするところは、耐食性及び耐摩耗性が高く、且つ、摺動層の樹脂組成物と多孔質焼結層との接合が強い摺動部材を提供することにある。 The present invention has been made in view of the above-described circumstances, and the object thereof is high corrosion resistance and wear resistance, and strong bonding between the resin composition of the sliding layer and the porous sintered layer. The object is to provide a sliding member.
上記した目的を達成するために、請求項１に係る発明においては、裏金層と摺動層とからなり、前記摺動層は、前記裏金層の表面に形成された多孔質焼結層と該多孔質焼結層の空孔部及び表面に含浸被覆された樹脂組成物とからなる摺動部材において、前記多孔質焼結層は、断面視において前記裏金層の表面に複数個積層された粒状の鋼相と、前記粒状の鋼相どうし及び前記粒状の鋼相と前記裏金層とをつなぐバインダとして機能するＮｉ−Ｐ合金相と、からなり、前記粒状の鋼相は、炭素の含有量が０．８〜１．３質量％の炭素鋼であるとともに、組織がフェライト相と、パーライト相とセメンタイト相との混合相と、からなり、前記断面視において複数個積層された粒状の鋼相のうち、前記多孔質焼結層の摺動面側に配置された摺動面側鋼相粒群では、前記粒状の鋼相の組織中の前記フェライト相の平均面積率が１０％以下である一方、前記多孔質焼結層の前記裏金層との界面側に配置された界面側鋼相粒群では、前記粒状の鋼相の組織中の前記フェライト相の平均面積率が２０％以上であることを特徴とする。 In order to achieve the above object, in the invention according to claim 1, the invention comprises a backing metal layer and a sliding layer, and the sliding layer comprises a porous sintered layer formed on the surface of the backing metal layer, and the sliding layer. In the sliding member comprising the pore portion of the porous sintered layer and the resin composition impregnated and coated on the surface, the porous sintered layer is a plurality of particles laminated on the surface of the back metal layer in a sectional view. And a Ni-P alloy phase functioning as a binder connecting the granular steel phases and the granular steel phases and the back metal layer, and the granular steel phases have a carbon content. The carbon steel is 0.8 to 1.3% by mass, and the structure is composed of a ferrite phase and a mixed phase of a pearlite phase and a cementite phase. Among them, the sliding surface side arranged on the sliding surface side of the porous sintered layer In the phase grain group, the average area ratio of the ferrite phase in the structure of the granular steel phase is 10% or less, while the interface side steel disposed on the interface side of the porous sintered layer with the back metal layer. In the phase grain group, the average area ratio of the ferrite phase in the structure of the granular steel phase is 20% or more.
請求項２に係る発明においては、請求項１記載の摺動部材において、前記粒状の鋼相の平均粒径は、４５〜１８０μｍであることを特徴とする。 In the invention which concerns on Claim 2, the average particle diameter of the said granular steel phase is 45-180 micrometers in the sliding member of Claim 1, It is characterized by the above-mentioned.
請求項３に係る発明においては、請求項１又は請求項２記載の摺動部材において、前記粒状の鋼相の表面には、前記Ｎｉ−Ｐ合金相のＮｉ成分が拡散していることを特徴とする。 In the invention according to claim 3, in the sliding member according to claim 1 or 2, the Ni component of the Ni-P alloy phase is diffused on the surface of the granular steel phase. And
請求項４に係る発明においては、請求項１乃至請求項３のいずれかに記載の摺動部材において、前記界面側鋼相粒群では、前記粒状の鋼相の表面における前記フェライト相の面積率が５０％以上であるものが、前記粒状の鋼相の全体に対する体積割合で５０％以上であることを特徴とする。 In the invention which concerns on Claim 4, in the sliding member in any one of Claim 1 thru | or 3, in the said interface side steel phase grain group, the area ratio of the said ferrite phase in the surface of the said granular steel phase Is 50% or more as a volume ratio with respect to the whole of the granular steel phase.
請求項５に係る発明においては、請求項１乃至請求項４のいずれかに記載の摺動部材において、前記Ｎｉ−Ｐ合金相の組成は、９〜１３質量％のＰと残部Ｎｉおよび不可避不純物からなることを特徴とする。 In the invention which concerns on Claim 5, in the sliding member in any one of Claim 1 thru | or 4, the composition of the said Ni-P alloy phase is 9-13 mass% P, remainder Ni, and an unavoidable impurity It is characterized by comprising.
請求項６に係る発明においては、請求項１乃至請求項４のいずれかに記載の摺動部材において、前記Ｎｉ−Ｐ合金相の組成は、９〜１３質量％のＰ、及び選択成分として１〜４質量％のＢ、１〜１２質量％のＳｉ、１〜１２質量％のＣｒ、１〜３質量％のＦｅ、０．５〜５質量％のＳｎ、０．５〜５質量％のＣｕから選択される１種以上を含有し、残部Ｎｉおよび不可避不純物からなることを特徴とする。 In the invention which concerns on Claim 6, in the sliding member in any one of Claim 1 thru | or 4, the composition of the said Ni-P alloy phase is 9-13 mass% P, and is 1 as a selective component. ~ 4 mass% B, 1-12 mass% Si, 1-12 mass% Cr, 1-3 mass% Fe, 0.5-5 mass% Sn, 0.5-5 mass% Cu It contains at least one selected from the group consisting of the remaining Ni and inevitable impurities.
請求項７に係る発明においては、請求項１乃至請求項６のいずれかに記載の摺動部材において、前記多孔質焼結層における前記Ｎｉ−Ｐ合金相の割合は、前記多孔質焼結層の１００質量部に対して前記Ｎｉ−Ｐ合金相が５〜３０質量部であることを特徴とする。 In the invention which concerns on Claim 7, in the sliding member in any one of Claims 1 thru | or 6, the ratio of the said Ni-P alloy phase in the said porous sintered layer is the said porous sintered layer. The Ni-P alloy phase is 5 to 30 parts by mass with respect to 100 parts by mass.
請求項１に係る発明においては、摺動層を構成する多孔質焼結層は、断面視において裏金層の表面に複数個積層された粒状の鋼相と、粒状の鋼相どうし及び粒状の鋼相と裏金層とをつなぐバインダとして機能するＮｉ−Ｐ合金相と、からなり、有機酸や硫黄成分に対する耐食性が高い。また、鋼相は、炭素の含有量が０．８〜１．３質量％の炭素鋼であるとともに、組織がフェライト相と、パーライト相とセメンタイト相の混合相と、からなるが、炭素の含有量が０．８質量％未満の炭素鋼を用いる場合には、多孔質焼結層の強度が低く、摺動部材の耐摩耗性が不十分となる。一方、炭素の含有量が１．３質量％を超える炭素鋼を用いる場合には、後述する界面側鋼相粒群の鋼相の組織中のフェライト相の平均面積率が２０％未満になりやすい。 In the invention according to claim 1, the porous sintered layer constituting the sliding layer includes a plurality of granular steel phases laminated on the surface of the back metal layer in a cross-sectional view, granular steel phases, and granular steel. It consists of a Ni-P alloy phase that functions as a binder that connects the phase and the back metal layer, and has high corrosion resistance to organic acids and sulfur components. The steel phase is a carbon steel having a carbon content of 0.8 to 1.3% by mass, and the structure is composed of a ferrite phase and a mixed phase of a pearlite phase and a cementite phase. When carbon steel having an amount of less than 0.8% by mass is used, the strength of the porous sintered layer is low, and the wear resistance of the sliding member becomes insufficient. On the other hand, when a carbon steel having a carbon content exceeding 1.3% by mass is used, the average area ratio of the ferrite phase in the steel phase structure of the interface-side steel phase grain group described later tends to be less than 20%. .
また、断面視において複数個積層された粒状の鋼相のうち、多孔質焼結層の摺動面側に配置された摺動面側鋼相粒群では、粒状の鋼相の組織中のフェライト相の平均面積率が１０％以下であることで、多孔質焼結層の耐摩耗性が高くなる。詳しくは、摺動部材が使用され、多孔質焼結層の表面に被覆した樹脂組成物が摩耗した場合には、摺動面に摺動面側鋼相粒群の粒状の鋼相が露出するようになるが、摺動面側鋼相粒群の粒状の鋼相は、組織中のフェライト相の平均面積率が１０％以下であり、硬い鋼相であることから、摺動層の耐摩耗性が高くなる。なお、摺動面側鋼相粒群の粒状の鋼相の組織中のフェライト相の平均面積率が１０％を超えると、摺動層の耐摩耗性を高める効果が低下する。一方、多孔質焼結層の裏金層との界面側に配置された界面側鋼相粒群では、粒状の鋼相の組織中のフェライト相の平均面積率が２０％以上であることで、摺動層の樹脂組成物と界面側鋼相粒群の鋼相との界面での熱膨張量の差が小さく、その界面でのせん断が起き難くなり、摺動層の樹脂組成物と粒状の鋼相との接合を強くすることができ、同時に、Ｎｉ−Ｐ合金相と界面側鋼相粒群の鋼相との界面でのせん断が起き難くなり、多孔質焼結層の強度を高めることができる。 Moreover, among the granular steel phases laminated in cross-section, the sliding surface side steel phase grain group arranged on the sliding surface side of the porous sintered layer has a ferrite in the structure of the granular steel phase. When the average area ratio of the phase is 10% or less, the wear resistance of the porous sintered layer is increased. Specifically, when a sliding member is used and the resin composition coated on the surface of the porous sintered layer is worn, the granular steel phase of the sliding surface side steel phase grain group is exposed on the sliding surface. However, since the granular steel phase of the sliding surface side steel phase grain group is a hard steel phase with an average area ratio of the ferrite phase in the structure being 10% or less, the wear resistance of the sliding layer Increases nature. In addition, when the average area ratio of the ferrite phase in the structure of the granular steel phase of the sliding surface side steel phase grain group exceeds 10%, the effect of increasing the wear resistance of the sliding layer is lowered. On the other hand, in the interface-side steel phase grain group arranged on the interface side with the back metal layer of the porous sintered layer, the average area ratio of the ferrite phase in the structure of the granular steel phase is 20% or more. The difference in thermal expansion at the interface between the resin composition of the dynamic layer and the steel phase of the interface-side steel phase grain group is small, making it difficult for shear to occur at the interface, and the resin composition of the sliding layer and the granular steel It is possible to increase the strength of the porous sintered layer because it is difficult to cause shearing at the interface between the Ni-P alloy phase and the steel phase of the interface-side steel phase grain group. it can.
本実施形態に係る摺動部材１について、図１乃至図３を参照して説明する。図１は、裏金層２の表面にＮｉ−Ｐ合金相７と粒状の鋼相６とからなる多孔質焼結層４と樹脂組成物５とからなる摺動層３を形成した摺動部材１の断面を示す模式図である。図２は、摺動面側鋼相粒群６ＵＧの粒状の鋼相６Ｕの組織を示す拡大図である。図３は、界面側鋼相粒群６ＬＧの粒状の鋼相６Ｌの組織を示す拡大図である。 A sliding member 1 according to this embodiment will be described with reference to FIGS. 1 to 3. 1 shows a sliding member 1 in which a sliding layer 3 composed of a porous sintered layer 4 composed of a Ni—P alloy phase 7 and a granular steel phase 6 and a resin composition 5 is formed on the surface of a backing metal layer 2. It is a schematic diagram which shows the cross section. FIG. 2 is an enlarged view showing the structure of the granular steel phase 6U of the sliding surface side steel phase grain group 6UG. FIG. 3 is an enlarged view showing the structure of the granular steel phase 6L of the interface-side steel phase grain group 6LG.
図１に示すように、摺動部材１は、裏金層２と摺動層３とからなり、摺動層３は、裏金層２上に形成された多孔質焼結層４と該多孔質焼結層の空孔部および表面に含浸被覆された樹脂組成物５とからなる。また、多孔質焼結層４は、粒状の鋼相６とＮｉ−Ｐ合金相７とからなる。この粒状の鋼相６は、摺動部材１の摺動面に対して垂直方向の断面視において、裏金層２の表面に複数個（図１では２個）積層されている。また、Ｎｉ−Ｐ合金相７は、鋼相６の粒どうし、あるいは、鋼相６の粒と裏金層２の表面とをつなぐバインダとして機能し、鋼相６の粒どうし、あるいは、鋼相６の粒と裏金層２の表面とは、Ｎｉ−Ｐ合金相７を介して接合している。なお、鋼相６の粒どうし、あるいは、鋼相６の粒と裏金層２の表面とは、直接、接触、あるいは、焼結により接合している部分が形成されていてもよい。また、鋼相６の粒は、表面の一部がＮｉ−Ｐ合金相７により覆われていない部分が形成されているが、鋼相６の粒の表面の全てがＮｉ−Ｐ合金相７により覆われていてもよい。ただし、多孔質焼結層４の摺動面側に配置された鋼相６Ｕは、粒の表面のうち摺動面側の表面がＮｉ−Ｐ合金相７により覆われないようにすることが好ましい。また、多孔質焼結層４は、樹脂組成物５を含浸させるための空孔を有し、その空孔率は１０〜６０％である。より好ましくは、空孔率は２０〜４０％である。 As shown in FIG. 1, the sliding member 1 includes a backing metal layer 2 and a sliding layer 3, and the sliding layer 3 includes a porous sintered layer 4 formed on the backing metal layer 2 and the porous firing layer. And a resin composition 5 impregnated and coated on the surface of the pores of the binder layer. The porous sintered layer 4 includes a granular steel phase 6 and a Ni—P alloy phase 7. A plurality (two in FIG. 1) of the granular steel phases 6 are laminated on the surface of the back metal layer 2 in a cross-sectional view perpendicular to the sliding surface of the sliding member 1. The Ni-P alloy phase 7 functions as a binder that connects the grains of the steel phase 6 or the grains of the steel phase 6 and the surface of the back metal layer 2, and the grains of the steel phase 6 or the steel phase 6 The grains and the surface of the back metal layer 2 are bonded via the Ni-P alloy phase 7. The grains of the steel phase 6 or the grains of the steel phase 6 and the surface of the back metal layer 2 may be formed with a portion that is directly contacted or joined by sintering. Moreover, although the part of the surface of the grain of the steel phase 6 is not covered with the Ni—P alloy phase 7, all the surface of the grain of the steel phase 6 is made of the Ni—P alloy phase 7. It may be covered. However, it is preferable that the steel phase 6U disposed on the sliding surface side of the porous sintered layer 4 does not cover the surface on the sliding surface side of the grain surface with the Ni-P alloy phase 7. . The porous sintered layer 4 has pores for impregnating the resin composition 5, and the porosity is 10 to 60%. More preferably, the porosity is 20 to 40%.
粒状の鋼相６の組成は、炭素成分を０．８質量％〜１．３質量％含有する炭素鋼であり、一般市販されるアトマイズ法による粒状の過共析鋼を用いることができる。このような炭素鋼を用いることで、有機酸や硫黄成分に対する耐食性は、従来の銅合金を用いるよりも優れている。なお、粒状の鋼相６の組成は、前記炭素成分を含有し、さらに、１．３質量％以下のＳｉ、１．３質量％以下のＭｎ、０．０５質量％以下のＰ、０．０５質量％以下のＳのいずれか１種以上を含有し、残部Ｆｅおよび不可避不純物からなる組成であってもよい。また、鋼相６の組織は、フェライト相９と、パーライト相とセメンタイト相との混合相１０と、からなるが、微細な析出物（走査電子顕微鏡を用い１０００倍で組織観察を行っても検出できない析出物相）を含むことは許容される。また、粒状の鋼相６は、その表面（Ｎｉ−Ｐ合金相７との界面となる表面）に、Ｎｉ−Ｐ合金相７の成分との反応相が形成されていてもよい。そして、このような粒状の鋼相６とＮｉ−Ｐ合金相７とから多孔質焼結層４が構成されていることで、有機酸や硫黄成分に対する耐食性に優れている。 The composition of the granular steel phase 6 is a carbon steel containing 0.8% by mass to 1.3% by mass of a carbon component, and a granular hypereutectoid steel obtained by an atomization method that is commercially available can be used. By using such carbon steel, the corrosion resistance to organic acids and sulfur components is superior to that of using conventional copper alloys. In addition, the composition of the granular steel phase 6 contains the carbon component, and further 1.3 wt% or less of Si, 1.3 wt% or less of Mn, 0.05 wt% or less of P, 0.05 The composition may contain any one or more of S of less than or equal to mass% and consist of the remaining Fe and inevitable impurities. Further, the structure of the steel phase 6 is composed of a ferrite phase 9 and a mixed phase 10 of a pearlite phase and a cementite phase, but it is detected even if fine precipitates (observation of the structure at 1000 times using a scanning electron microscope) Including a non-precipitate precipitate phase). In addition, the granular steel phase 6 may have a reaction phase with a component of the Ni—P alloy phase 7 formed on the surface thereof (the surface serving as an interface with the Ni—P alloy phase 7). And since the porous sintered layer 4 is comprised from such a granular steel phase 6 and the Ni-P alloy phase 7, it is excellent in the corrosion resistance with respect to an organic acid or a sulfur component.
また、粒状の鋼相６の組織は、フェライト相９と、パーライト相とセメンタイト相との混合相１０と、からなるが、摺動部材１の断面視において裏金層２上に複数個積層された鋼相６のうち、多孔質焼結層４の摺動面側に配置された摺動面側鋼相粒群６ＵＧの鋼相６Ｕは、組織中のフェライト相９の平均面積率が１０％以下となっており、一方、多孔質焼結層４の裏金層２との界面側に配置された界面側鋼相粒群６ＬＧの鋼相６Ｌは、組織中のフェライト相９の平均面積率が２０％以上となっている。なお、摺動部材１の摺動面に対して垂直方向の断面視において、多孔質焼結層４の表面側（摺動部材１の摺動面側の多孔質焼結層４の表面であって、図１において上側）に配置された複数の鋼相６のうち、鋼相６の粒の表面が、最も上側に位置している鋼相６の粒の表面（摺動面に最も近い表面の頂部）を基準点Ｐとし、この基準点Ｐを通り摺動面に対して平行な仮想線（図１の破線で示す線）を多孔質焼結層４の表面Ｆとする。上記した摺動面側鋼相粒群６ＵＧは、多孔質焼結層４の粒状の鋼相６のうち、多孔質焼結層の表面Ｆから裏金層２の界面側に向かって鋼相６の粒の平均粒径の値の半分に相当する深さＤ１の範囲内に鋼相６の断面の少なくとも一部が含まれる鋼相６Ｕの集まりである。また、界面側鋼相粒群６ＬＧは、多孔質焼結層４の粒状の鋼相６のうち、摺動面側鋼相粒群６ＵＧの鋼相６Ｕより裏金層２との界面側に配置された鋼相６Ｌの集まりであって、摺動面側鋼相粒群６ＵＧの鋼相６Ｕを除く鋼相６Ｌの集まりである。 The structure of the granular steel phase 6 is composed of a ferrite phase 9 and a mixed phase 10 of a pearlite phase and a cementite phase, and a plurality of layers are laminated on the back metal layer 2 in a sectional view of the sliding member 1. Among the steel phases 6, the steel phase 6U of the sliding surface side steel phase grain group 6UG arranged on the sliding surface side of the porous sintered layer 4 has an average area ratio of the ferrite phase 9 in the structure of 10% or less. On the other hand, in the steel phase 6L of the interface-side steel phase grain group 6LG arranged on the interface side of the porous sintered layer 4 with the back metal layer 2, the average area ratio of the ferrite phase 9 in the structure is 20 % Or more. Note that, in a cross-sectional view perpendicular to the sliding surface of the sliding member 1, the surface side of the porous sintered layer 4 (the surface of the porous sintered layer 4 on the sliding surface side of the sliding member 1). Among the plurality of steel phases 6 arranged on the upper side in FIG. 1, the surface of the grain of the steel phase 6 is the surface of the grain of the steel phase 6 located on the uppermost side (the surface closest to the sliding surface). ) Is defined as a reference point P, and a virtual line (line indicated by a broken line in FIG. 1) passing through the reference point P and parallel to the sliding surface is defined as a surface F of the porous sintered layer 4. The sliding surface side steel phase grain group 6UG described above includes the steel phase 6 of the granular steel phase 6 of the porous sintered layer 4 from the surface F of the porous sintered layer toward the interface side of the back metal layer 2. This is a group of steel phases 6U in which at least a part of the cross section of the steel phase 6 is included in the range of the depth D1 corresponding to half of the value of the average grain size of the grains. The interface-side steel phase grain group 6LG is arranged on the interface side with the back metal layer 2 from the steel phase 6U of the sliding surface-side steel phase grain group 6UG in the granular steel phase 6 of the porous sintered layer 4. This is a group of steel phases 6L excluding the steel phase 6U of the sliding surface side steel phase grain group 6UG.
なお、多孔質焼結層４における粒状の鋼相６は、平均粒径が４５〜１８０μｍであればよい。このような平均粒径の鋼相６を用いることで、多孔質焼結層４には、樹脂組成物５を含浸させるために好適な空孔が形成される。鋼相６の平均粒径が４５μｍ未満であると、多孔質焼結層４に形成される各空孔部のサイズが小さくなり、樹脂組成物５を含浸させ難くなる。一方、鋼相６の平均粒径が１８０μｍを超えると、界面側鋼相粒群６ＬＧの鋼相６Ｌの組織中のフェライト相９の割合が少なくなる場合がある。 In addition, the granular steel phase 6 in the porous sintered layer 4 should just have an average particle diameter of 45-180 micrometers. By using the steel phase 6 having such an average particle diameter, pores suitable for impregnating the resin composition 5 are formed in the porous sintered layer 4. When the average particle size of the steel phase 6 is less than 45 μm, the size of each hole formed in the porous sintered layer 4 becomes small, and it becomes difficult to impregnate the resin composition 5. On the other hand, when the average particle diameter of the steel phase 6 exceeds 180 μm, the ratio of the ferrite phase 9 in the structure of the steel phase 6L of the interface-side steel phase grain group 6LG may decrease.
Ｎｉ−Ｐ合金相７の組成は、９〜１３質量％のＰと残部Ｎｉおよび不可避不純物からなる。このＮｉ−Ｐ合金相７の組成は、Ｎｉ−Ｐ合金の融点が低くなる組成範囲である。なお、Ｎｉ−Ｐ合金相７の組成は、１０〜１２質量％のＰと残部Ｎｉおよび不可避不純物からなることがより望ましい。裏金層２上に多孔質焼結層４を焼結するときの昇温過程では、後述するが、多孔質焼結層４のＮｉ−Ｐ合金相７成分の全てを液相化させて、Ｎｉ成分を鋼相６の表面に拡散させる。このＮｉ成分の鋼相６の表面への拡散は、鋼相６の組織中のフェライト相９の形成に関係している。また、Ｎｉ−Ｐ合金相７の組成において、Ｐの含有量が９質量％未満、あるいは１３質量％を超えると、Ｎｉ−Ｐ合金の融点が高くなる。これにより、焼結時、Ｎｉ−Ｐ合金の液相の発生量が減少し、Ｎｉ成分が鋼相６の表面に拡散し難くなり、鋼相６の組織中にフェライト相９が形成され難くなる。 The composition of the Ni-P alloy phase 7 consists of 9 to 13% by mass of P, the balance Ni and unavoidable impurities. The composition of the Ni—P alloy phase 7 is a composition range in which the melting point of the Ni—P alloy is lowered. The composition of the Ni-P alloy phase 7 is more preferably composed of 10 to 12% by mass of P, the remaining Ni and inevitable impurities. In the temperature raising process when the porous sintered layer 4 is sintered on the back metal layer 2, as will be described later, all of the seven components of the Ni-P alloy phase of the porous sintered layer 4 are made into a liquid phase, and Ni The components are diffused on the surface of the steel phase 6. The diffusion of the Ni component to the surface of the steel phase 6 is related to the formation of the ferrite phase 9 in the structure of the steel phase 6. Further, in the composition of the Ni—P alloy phase 7, when the P content is less than 9 mass% or exceeds 13 mass%, the melting point of the Ni—P alloy becomes high. As a result, the amount of the liquid phase of the Ni—P alloy is reduced during sintering, the Ni component is less likely to diffuse to the surface of the steel phase 6, and the ferrite phase 9 is less likely to be formed in the structure of the steel phase 6. .
なお、Ｎｉ−Ｐ合金相７は、前記組成に、さらに、選択成分として１〜４質量％のＢ、１〜１２質量％のＳｉ、１〜１２質量％のＣｒ、１〜３質量％のＦｅ、０．５〜５質量％のＳｎ、０．５〜５質量％のＣｕから選択される１種以上を含有させて、Ｎｉ−Ｐ合金相７の強度を調整してもよい。このように、Ｎｉ−Ｐ合金相７は、これらの選択成分を含有しても、鋼相６の組織中のフェライト相９の形成には影響しない。なお、選択成分の中でＣｕ成分をＮｉ−Ｐ合金相７に含有させる場合、Ｎｉ−Ｐ合金相７の耐食性に影響を及ぼさないようにするため、その含有量は５質量％以下にする必要がある。また、これら選択成分を含有するＮｉ−Ｐ合金相７は、Ｎｉ素地部が必須成分であるＰ及び選択成分であるＢ、Ｓｉ、Ｃｒ、Ｆｅ、Ｓｎ、Ｃｕを固溶した形態の組織が好ましいが、Ｎｉ素地部が含有成分による２次相（析出物、晶出物）を含んだ形態の組織であってもよい。 In addition, the Ni-P alloy phase 7 is further added to the above composition as an optional component of 1 to 4% by mass of B, 1 to 12% by mass of Si, 1 to 12% by mass of Cr, and 1 to 3% by mass of Fe. The strength of the Ni-P alloy phase 7 may be adjusted by adding one or more selected from 0.5 to 5% by mass of Sn and 0.5 to 5% by mass of Cu. Thus, even if the Ni-P alloy phase 7 contains these selective components, it does not affect the formation of the ferrite phase 9 in the structure of the steel phase 6. In addition, in order to prevent the corrosion resistance of the Ni-P alloy phase 7 from being affected when the Cu component is included in the Ni-P alloy phase 7 among the selected components, the content needs to be 5% by mass or less. There is. Further, the Ni—P alloy phase 7 containing these selective components preferably has a structure in which the Ni base portion is a solid solution with P as an essential component and B, Si, Cr, Fe, Sn, and Cu as selective components. However, the Ni base portion may have a structure including a secondary phase (precipitate and crystallized product) due to the contained component.
多孔質焼結層４におけるＮｉ−Ｐ合金相７の割合は、多孔質焼結層４の１００質量部に対してＮｉ−Ｐ合金相７が５〜３０質量部であり、より好ましくは、１０〜２０質量部である。このＮｉ−Ｐ合金相７の割合は、鋼相６の粒どうし、あるいは、鋼相６の粒と裏金層２の表面とを結びつけるバインダとなる形態の多孔質焼結層４を形成するために好適な範囲である。Ｎｉ−Ｐ合金相７の割合が５質量部未満であると、多孔質焼結層４の強度や、多孔質焼結層４と裏金層２との接合が不十分となる。一方、Ｎｉ−Ｐ合金相７の割合が３０質量部を超えると、焼結時、空孔となるべき部分がＮｉ−Ｐ合金の液相で充填されてしまうので、多孔質焼結層４の空孔率が小さくなりすぎるようになり、また、摺動面側鋼相粒群６ＵＧの鋼相６Ｕの組織中のフェライト相９の割合が多くなってしまう。 The ratio of the Ni—P alloy phase 7 in the porous sintered layer 4 is 5 to 30 parts by mass with respect to 100 parts by mass of the porous sintered layer 4, more preferably 10 ˜20 parts by mass. The ratio of the Ni—P alloy phase 7 is used to form the porous sintered layer 4 in a form that serves as a binder for connecting the grains of the steel phase 6 or the grains of the steel phase 6 and the surface of the back metal layer 2. It is a suitable range. When the proportion of the Ni-P alloy phase 7 is less than 5 parts by mass, the strength of the porous sintered layer 4 and the bonding between the porous sintered layer 4 and the back metal layer 2 are insufficient. On the other hand, when the proportion of the Ni-P alloy phase 7 exceeds 30 parts by mass, the portion to be vacant during the sintering is filled with the liquid phase of the Ni-P alloy. The porosity becomes too small, and the ratio of the ferrite phase 9 in the structure of the steel phase 6U of the sliding surface side steel phase grain group 6UG increases.
樹脂組成物５は、多孔質焼結層４の空孔部および表面に含浸被覆される。図２及び図３に示すように、樹脂組成物５は、多孔質焼結層４の粒状の鋼相６の表面、あるいは、Ｎｉ−Ｐ合金相７の表面と接している。樹脂組成物５としては、一般的な摺動用の樹脂組成物を用いることができる。具体的には、フッ素樹脂、ポリエーテルエーテルケトン、 ポリアミド、ポリイミド、ポリアミドイミド、ポリベンゾイミダゾール、エポキシ、フェノール、ポリアセタール、ポリエチレン、ポリプロピレン、ポリオレフィン、ポリフェニレンサルファイドのいずれか一種以上の樹脂に、さらに、固体潤滑剤としてグラファイト、グラフェン、フッ化黒鉛、二硫化モリブデン、フッ素樹脂、ポリエチレン、ポリオレフィン、窒化ホウ素、二硫化錫のいずれか一種以上を含む樹脂組成物を用いることができる。また、樹脂組成物５には、さらに充填剤として、粒状、あるいは、繊維状の金属、金属化合物、セラミック、無機化合物、有機化合物のいずれか一種以上を含有させることができる。なお、樹脂組成物５を構成する樹脂、固体潤滑剤、充填剤は、ここで例示したものに限定されない。 The resin composition 5 is impregnated and coated on the pores and the surface of the porous sintered layer 4. As shown in FIGS. 2 and 3, the resin composition 5 is in contact with the surface of the granular steel phase 6 of the porous sintered layer 4 or the surface of the Ni—P alloy phase 7. As the resin composition 5, a general sliding resin composition can be used. Specifically, any one or more of fluororesin, polyetheretherketone, polyamide, polyimide, polyamideimide, polybenzimidazole, epoxy, phenol, polyacetal, polyethylene, polypropylene, polyolefin, polyphenylene sulfide, and solid As the lubricant, a resin composition containing any one or more of graphite, graphene, graphite fluoride, molybdenum disulfide, fluororesin, polyethylene, polyolefin, boron nitride, and tin disulfide can be used. Further, the resin composition 5 may further contain one or more of granular or fibrous metals, metal compounds, ceramics, inorganic compounds, and organic compounds as fillers. In addition, the resin, the solid lubricant, and the filler constituting the resin composition 5 are not limited to those exemplified here.
図２に示すように、摺動面側鋼相粒群６ＵＧの鋼相６Ｕの組織は、フェライト相９と、パーライト相とセメンタイト相との混合相１０と、からなり、摺動面側鋼相粒群６ＵＧの鋼相６Ｕは、組織中のフェライト相９の平均面積率が１０％以下となっている。また、図２に示すように、摺動面側鋼相粒群６ＵＧの鋼相６Ｕは、粒の表面のうち摺動面側の表面がＮｉ−Ｐ合金相７により覆われていないが、該摺動面側の表面付近では、組織中のフェライト相９が特に少なくなっている。一方、鋼相６Ｕは、粒の表面のうち裏金層２側の表面がバインダであるＮｉ−Ｐ合金相７と接するが、裏金層２側の表面付近では、組織中のフェライト相９が多くなっている。 As shown in FIG. 2, the structure of the steel phase 6U of the sliding surface side steel phase grain group 6UG is composed of a ferrite phase 9 and a mixed phase 10 of a pearlite phase and a cementite phase. In the steel phase 6U of the grain group 6UG, the average area ratio of the ferrite phase 9 in the structure is 10% or less. Further, as shown in FIG. 2, the steel phase 6U of the sliding surface side steel phase grain group 6UG is not covered with the Ni-P alloy phase 7 in the surface of the sliding surface side of the grain surface. Near the surface on the sliding surface side, the ferrite phase 9 in the structure is particularly small. On the other hand, the steel phase 6U is in contact with the Ni-P alloy phase 7 which is the binder on the back metal layer 2 side of the grain surface, but the ferrite phase 9 in the structure increases in the vicinity of the surface on the back metal layer 2 side. ing.
図３に示すように、界面側鋼相粒群６ＬＧの鋼相６Ｌの組織は、フェライト相９と、パーライト相とセメンタイト相の混合相１０と、からなり、界面側鋼相粒群６ＬＧの鋼相６Ｌは、組織中のフェライト相９の平均面積率が２０％以上となっている。鋼相６Ｌにおけるフェライト相９は、炭素成分の含有量が最大で０．０２質量％と少なく、純鉄に近い組成の相である。一方、鋼相６Ｌにおけるパーライト相とセメンタイト相との混合相１０は、フェライト相と鉄炭化物であるセメンタイト相（Ｆｅ３Ｃ）とが薄い板状に交互に並んで形成されるラメラ組織の相であるパーライト相と、鉄炭化物であるセメンタイト相と、が混在した相である。また、パーライト相とセメンタイト相との混合相１０は、フェライト相９よりも炭素成分の量が多く、フェライト相９よりも硬い相である。そして、図３に示すように、樹脂組成物５あるいはＮｉ−Ｐ合金相７との界面となる鋼相６Ｌの表面付近の組織中には、鋼相６Ｌの粒の中心部における組織中よりも多くのフェライト相９が形成されている。なお、本発明におけるフェライト相９は、前記したパーライト相を構成するフェライト相を含まない。また、パーライト相とセメンタイト相との混合相１０は、ベイナイト相、ソルバイト相、トールースタイト相、マルテンサイト相を含んでいてもよい。 As shown in FIG. 3, the structure of the steel phase 6L of the interface-side steel phase grain group 6LG is composed of a ferrite phase 9 and a mixed phase 10 of a pearlite phase and a cementite phase, and the steel of the interface-side steel phase grain group 6LG. In the phase 6L, the average area ratio of the ferrite phase 9 in the structure is 20% or more. The ferrite phase 9 in the steel phase 6L is a phase having a composition close to that of pure iron, with a maximum carbon component content of 0.02% by mass. On the other hand, the mixed phase 10 of the pearlite phase and the cementite phase in the steel phase 6L is a lamellar structure phase in which the ferrite phase and the cementite phase (Fe 3 C) that is iron carbide are alternately arranged in a thin plate shape. It is a phase in which a certain pearlite phase and a cementite phase that is iron carbide are mixed. Further, the mixed phase 10 of the pearlite phase and the cementite phase has a larger amount of carbon component than the ferrite phase 9 and is a harder phase than the ferrite phase 9. As shown in FIG. 3, the structure near the surface of the steel phase 6 </ b> L serving as the interface with the resin composition 5 or the Ni—P alloy phase 7 is more than in the structure at the center of the grain of the steel phase 6 </ b> L. Many ferrite phases 9 are formed. In addition, the ferrite phase 9 in this invention does not contain the ferrite phase which comprises an above described pearlite phase. Further, the mixed phase 10 of the pearlite phase and the cementite phase may include a bainite phase, a sorbite phase, a tallostite phase, and a martensite phase.
なお、図２に示す摺動面側鋼相粒群６ＵＧの鋼相６Ｕの組織、及び図３に示す界面鋼相粒群６ＬＧの鋼相６Ｌの組織は、一例であり、図２や図３に示す組織には限定されない。鋼相６Ｕ及び鋼相６Ｌは、粒の表面の全体がＮｉ−Ｐ合金相７により覆われた形態でもよく、また、組織中にフェライト相９が均一に分布した形態であってもよい。 The structure of the steel phase 6U of the sliding surface side steel phase grain group 6UG shown in FIG. 2 and the structure of the steel phase 6L of the interface steel phase grain group 6LG shown in FIG. 3 are examples, and FIG. 2 and FIG. It is not limited to the organization shown. The steel phase 6U and the steel phase 6L may have a form in which the entire grain surface is covered with the Ni-P alloy phase 7, or a form in which the ferrite phase 9 is uniformly distributed in the structure.
本実施形態では、電子顕微鏡を用いて摺動部材１の厚さ方向に対して平行方向に切断された複数個所（例えば、３箇所）の断面組織を倍率５００倍で電子像を撮影し、その画像を一般的な画像解析手法（解析ソフト：Ｉｍａｇｅ−Ｐｒｏ Ｐｌｕｓ（Ｖｅｒｓｉｏｎ４．５）；（株）プラネトロン製）を用いて、まず、段落００２１で説明した摺動面側鋼相粒群６ＵＧの鋼相６Ｕと界面側鋼相粒群６ＬＧの鋼相６Ｌとの区分けを行う。次に、同手法を用い、摺動面側鋼相粒群６ＵＧの鋼相６Ｕの組織中のフェライト相９の平均面積率、および、界面側鋼相粒群６ＬＧの鋼相６Ｌの組織中のフェライト相９の平均面積率を測定する。 In the present embodiment, an electron image is taken at a magnification of 500 times of cross-sectional structures at a plurality of locations (for example, 3 locations) cut in a direction parallel to the thickness direction of the sliding member 1 using an electron microscope. Using a general image analysis method (analysis software: Image-Pro Plus (Version 4.5); manufactured by Planetron Co., Ltd.), first, the steel of the sliding surface side steel phase grain group 6UG described in paragraph 0021 is used. The phase 6U and the steel phase 6L of the interface side steel phase grain group 6LG are classified. Next, using the same method, the average area ratio of the ferrite phase 9 in the structure of the steel phase 6U of the sliding surface side steel phase grain group 6UG, and the structure of the steel phase 6L of the interface side steel phase grain group 6LG The average area ratio of the ferrite phase 9 is measured.
また、多孔質焼結層４の鋼相６には、Ｎｉ−Ｐ合金相７のＮｉ成分が拡散していることで、摺動層３の樹脂組成物５あるいはＮｉ−Ｐ合金相７との接合を強くすることができる。多孔質焼結層４のＮｉ−Ｐ合金相７から鋼相６に拡散したＮｉ成分は極微量であるが、ＥＰＭＡ（エレクトロンプローブマイクロアナライザー）測定により確認される。また、鋼相６の組織中のＮｉ成分は、鋼相６の表面付近のフェライト相９に固溶された形態で存在しており、樹脂組成物５あるいはＮｉ−Ｐ合金相７との界面となる鋼相６の表面から内部へ向かって次第にＮｉ成分の濃度が減少していることが確認できる。なお、鋼相６の組織中には、Ｎｉ３Ｐ（金属間化合物）の相が形成されていない。 Further, since the Ni component of the Ni—P alloy phase 7 is diffused in the steel phase 6 of the porous sintered layer 4, the resin composition 5 of the sliding layer 3 or the Ni—P alloy phase 7 is in contact with the steel phase 6. Bonding can be strengthened. The Ni component diffused from the Ni—P alloy phase 7 of the porous sintered layer 4 to the steel phase 6 is extremely small, but is confirmed by EPMA (Electron Probe Microanalyzer) measurement. Further, the Ni component in the structure of the steel phase 6 exists in the form of a solid solution in the ferrite phase 9 near the surface of the steel phase 6, and the interface with the resin composition 5 or the Ni—P alloy phase 7 It can be confirmed that the concentration of the Ni component gradually decreases from the surface of the steel phase 6 to the inside. In the structure of the steel phase 6, a Ni 3 P (intermetallic compound) phase is not formed.
図４は、別実施形態の界面側鋼相粒群６ＬＧの鋼相６Ｌの組織を示す拡大図である。この鋼相６Ｌは、図３に示した鋼相６Ｌよりも、粒の表面付近でフェライト相９が特に多く形成されている。界面側鋼相粒群６ＬＧの鋼相６Ｌは、図４に示すように、粒の表面でのフェライト相９の面積率が５０％以上であるものが、界面側鋼相粒群６ＬＧの鋼相６Ｌの全体に対する体積割合で５０％以上になっていることで、さらに、摺動層３の樹脂組成物５あるいはＮｉ−Ｐ合金相７との接合を強くすることができる。 FIG. 4 is an enlarged view showing the structure of the steel phase 6L of the interface-side steel phase grain group 6LG of another embodiment. In this steel phase 6L, more ferrite phase 9 is formed near the surface of the grains than in the steel phase 6L shown in FIG. As shown in FIG. 4, the steel phase 6L of the interface-side steel phase grain group 6LG has an area ratio of 50% or more of the ferrite phase 9 on the grain surface. By being 50% or more in the volume ratio with respect to the whole 6L, joining with the resin composition 5 or the Ni-P alloy phase 7 of the sliding layer 3 can be strengthened further.
なお、鋼相６Ｌの粒の表面におけるフェライト相９の面積率は、直接、測定はできないが、電子顕微鏡を用いて摺動部材１の厚さ方向に対して平行方向に切断された複数個所（例えば、３箇所）の断面組織を倍率５００倍で電子像を撮影し、その画像を一般的な画像解析手法（解析ソフト：Ｉｍａｇｅ−Ｐｒｏ Ｐｌｕｓ（Ｖｅｒｓｉｏｎ４．５）；（株）プラネトロン製）を用いて、画像中の各鋼相６Ｌの輪郭線の全長に対するフェライト相９による輪郭線の長さの割合（鋼相６Ｌの外周である輪郭線のうちフェライト相９に相当する部分の長さの割合）を測定することにより確認できる。次に、画像中の界面側鋼相粒群６ＬＧの全鋼相６Ｌの面積の和（Ａ１）と、粒の表面におけるフェライト相９の面積率が５０％以上であった鋼相６Ｌの面積の和（Ａ２）を測定し、その比（Ａ２／Ａ１）を算出することで、界面側鋼相粒群６ＬＧの鋼相６Ｌの全体積に対して粒の表面でのフェライト相９の面積率が５０％以上であった鋼相６Ｌの体積割合（体積率）を確認することができる。 In addition, although the area ratio of the ferrite phase 9 on the surface of the grain of the steel phase 6L cannot be directly measured, a plurality of locations (in a direction parallel to the thickness direction of the sliding member 1 using an electron microscope ( For example, an electronic image of a cross-sectional structure at three locations is taken at a magnification of 500 times, and the image is used using a general image analysis method (analysis software: Image-Pro Plus (Version 4.5); manufactured by Planetron Co., Ltd.). The ratio of the length of the contour line by the ferrite phase 9 to the total length of the contour line of each steel phase 6L in the image (the ratio of the length corresponding to the ferrite phase 9 in the contour line that is the outer periphery of the steel phase 6L) ) Can be confirmed by measuring. Next, the sum (A1) of the area of all the steel phases 6L of the interface side steel phase grain group 6LG in the image and the area of the steel phase 6L in which the area ratio of the ferrite phase 9 on the grain surface was 50% or more. By measuring the sum (A2) and calculating the ratio (A2 / A1), the area ratio of the ferrite phase 9 on the surface of the grains with respect to the total volume of the steel phase 6L of the interface-side steel phase grain group 6LG is The volume ratio (volume ratio) of the steel phase 6L, which was 50% or more, can be confirmed.
図５は、別実施形態の多孔質焼結層４を形成した摺動部材１の断面を示す模式図である。この多孔質焼結層４では、図５に示すように、摺動部材１の摺動面に対して垂直方向の断面視において、粒状の鋼相６が、裏金層２の表面に３個積層されており、図１に示した多孔質焼結層４よりも多くの粒状の鋼相６が、裏金層２の表面に積層されている。なお、粒状の鋼相６は、裏金層２の表面に４個以上積層されてもよい。 FIG. 5 is a schematic view showing a cross section of the sliding member 1 on which the porous sintered layer 4 of another embodiment is formed. In this porous sintered layer 4, as shown in FIG. 5, three granular steel phases 6 are laminated on the surface of the back metal layer 2 in a cross-sectional view perpendicular to the sliding surface of the sliding member 1. More granular steel phases 6 than the porous sintered layer 4 shown in FIG. 1 are laminated on the surface of the back metal layer 2. Four or more granular steel phases 6 may be laminated on the surface of the back metal layer 2.
次に、従来の摺動部材１１における摺動層１３の樹脂組成物１５と多孔質焼結層１４との接合について、図７を参照して説明する。図７は、従来の裏金層１２上に組織がパーライト相とセメンタイト相とからなる炭素鋼（過共析鋼）粉末を焼結し、多孔質焼結層１４を形成した摺動部材１１を示す模式図である。焼結後の多孔質焼結層１４の組織は、パーライト相とセメンタイト相とからなる。 Next, the joining of the resin composition 15 of the sliding layer 13 and the porous sintered layer 14 in the conventional sliding member 11 will be described with reference to FIG. FIG. 7 shows a sliding member 11 in which a porous sintered layer 14 is formed by sintering a carbon steel (hypereutectoid steel) powder whose structure is composed of a pearlite phase and a cementite phase on a conventional back metal layer 12. It is a schematic diagram. The structure of the sintered porous layer 14 after sintering consists of a pearlite phase and a cementite phase.
摺動層１３の樹脂組成物１５との界面となる多孔質焼結層１４の表面（炭素鋼の表面）は、パーライト相とセメンタイト相からなるので、摺動層１３の樹脂組成物１５との接合が弱い。図７に示すように、そのような多孔質焼結層１４を摺動部材１１として用いた場合、局部的に摺動層１３の樹脂組成物１５と多孔質焼結層１４との界面でせん断が起こる場合がある。これは、摺動部材１１が使用される温度が上昇すると、多孔質焼結層１４よりも摺動層１３の樹脂組成物１５の熱膨張量が大きいので、摺動層１３の樹脂組成物１５と多孔質焼結層１４との界面でせん断応力が発生するためである。 Since the surface (the surface of the carbon steel) of the porous sintered layer 14 that serves as an interface between the sliding layer 13 and the resin composition 15 is composed of a pearlite phase and a cementite phase, Bonding is weak. As shown in FIG. 7, when such a porous sintered layer 14 is used as the sliding member 11, shearing is locally performed at the interface between the resin composition 15 of the sliding layer 13 and the porous sintered layer 14. May happen. This is because when the temperature at which the sliding member 11 is used increases, the thermal expansion amount of the resin composition 15 of the sliding layer 13 is larger than that of the porous sintered layer 14, and thus the resin composition 15 of the sliding layer 13. This is because shear stress is generated at the interface between the porous sintered layer 14 and the porous sintered layer 14.
具体的には、多孔質焼結層１４におけるセメンタイト相およびパーライト相の熱膨張係数は、摺動部材１１の樹脂組成物１５の熱膨張係数よりも小さい。このため、摺動部材１１の温度が上昇したとき、摺動層１３の樹脂組成物１５と多孔質焼結層１４との熱膨張量の差によるせん断力で、摺動層１３の樹脂組成物１５と多孔質焼結層１４との界面でせん断が起こり易い。これに対し、本実施形態では、摺動層３の樹脂組成物５との界面となる多孔質焼結層４の鋼相６は、図７に示した従来の摺動部材１１と同じく、組織がパーライト相とセメンタイト相とからなる炭素鋼（過共析鋼）粉末を用いるが、焼結後の多孔質焼結層４の鋼相６の組織は、フェライト相９と、パーライト相とセメンタイト相との混合相１０と、からなる。この鋼相６は、Ｎｉ−Ｐ合金相７をバインダとし裏金層２の表面に複数個積層されているが、多孔質焼結層４の裏金層２との界面側に配置された界面側鋼相粒群６ＬＧでは、粒状の鋼相６Ｌの組織中のフェライト相９の平均面積率が２０％以上となっていることで、摺動層３の樹脂組成物５と界面側鋼相粒群６ＬＧの鋼相６Ｌの界面での熱膨張量の差が小さく、その界面でのせん断が起き難くなり、摺動層３の樹脂組成物５と粒状の鋼相６Ｌとの接合を強くすることができる。また、Ｎｉ−Ｐ合金相７と界面側鋼相粒群６ＬＧの鋼相６Ｌとの接合が強くなり、多孔質焼結層４の強度を高めることができる。 Specifically, the thermal expansion coefficients of the cementite phase and the pearlite phase in the porous sintered layer 14 are smaller than the thermal expansion coefficient of the resin composition 15 of the sliding member 11. For this reason, when the temperature of the sliding member 11 rises, the resin composition of the sliding layer 13 is caused by the shear force due to the difference in thermal expansion between the resin composition 15 of the sliding layer 13 and the porous sintered layer 14. Shear is likely to occur at the interface between 15 and the porous sintered layer 14. On the other hand, in the present embodiment, the steel phase 6 of the porous sintered layer 4 serving as the interface with the resin composition 5 of the sliding layer 3 has the same structure as the conventional sliding member 11 shown in FIG. Uses a carbon steel (hypereutectoid steel) powder composed of a pearlite phase and a cementite phase. The structure of the steel phase 6 of the sintered porous layer 4 after sintering is composed of a ferrite phase 9, a pearlite phase and a cementite phase. And a mixed phase 10. The steel phase 6 has a Ni-P alloy phase 7 as a binder and a plurality of layers are laminated on the surface of the back metal layer 2, but the interface side steel disposed on the interface side of the porous sintered layer 4 with the back metal layer 2. In the phase grain group 6LG, since the average area ratio of the ferrite phase 9 in the structure of the granular steel phase 6L is 20% or more, the resin composition 5 of the sliding layer 3 and the interface side steel phase grain group 6LG The difference in the amount of thermal expansion at the interface of the steel phase 6L is small, shearing at the interface is difficult to occur, and the bonding between the resin composition 5 of the sliding layer 3 and the granular steel phase 6L can be strengthened. . Moreover, the joining of the Ni-P alloy phase 7 and the steel phase 6L of the interface-side steel phase grain group 6LG becomes strong, and the strength of the porous sintered layer 4 can be increased.
なお、段落００２８に記載したが、セメンタイト相は鉄炭化物（Ｆｅ３Ｃ）であり、パーライト相は、このセメンタイトを含むために、熱膨張係数が小さいが、フェライト相９は、炭素成分の含有量が最大で０．０２質量％と少なく純鉄に近い組成の相であり、セメンタイト相やパーライト相に比べて熱膨張係数が大きく、摺動層３の樹脂組成物５との熱膨張係数の差が小さい。このため、摺動層３の樹脂組成物５との界面となる鋼相６Ｌの粒の表面に露出するフェライト相９の部分は、鋼相６Ｌの粒の表面と樹脂組成物５との界面での熱膨張量の差により発生するせん断力が低くなるので接合が強くなる。また、鋼相６Ｌのフェライト相９は、パーライト相とセメンタイト相との混合相１０と比べてＮｉ−Ｐ合金相７との接合が強いため、多孔質焼結層４の強度が高くなる。 Although described in paragraph 0028, the cementite phase is iron carbide (Fe 3 C), and the pearlite phase contains this cementite, so the coefficient of thermal expansion is small, but the ferrite phase 9 has a carbon component content. Is a phase having a composition as small as 0.02 mass% and close to pure iron, and has a larger thermal expansion coefficient than the cementite phase and the pearlite phase, and the difference in thermal expansion coefficient from the resin composition 5 of the sliding layer 3 Is small. For this reason, the portion of the ferrite phase 9 exposed on the surface of the grain of the steel phase 6L which becomes the interface with the resin composition 5 of the sliding layer 3 is the interface between the surface of the grain of the steel phase 6L and the resin composition 5. Since the shearing force generated due to the difference in thermal expansion between the two becomes lower, the bonding becomes stronger. Moreover, since the ferrite phase 9 of the steel phase 6L is strongly bonded to the Ni—P alloy phase 7 as compared with the mixed phase 10 of the pearlite phase and the cementite phase, the strength of the porous sintered layer 4 is increased.
一方、多孔質焼結層４の摺動面側に配置された摺動面側鋼相粒群６ＵＧの鋼相６Ｕは、組織中のフェライト相９の平均面積率が１０％以下となっている。摺動部材１が使用され、多孔質焼結層４の表面に被覆した樹脂組成物５が摩耗すると、多孔質焼結層４の摺動面側に配置された摺動面側鋼相粒群６ＵＧの粒状の鋼相６Ｕが露出するようになるが、鋼相６Ｕは、組織中のフェライト相９の平均面積率が１０％以下になっていることで十分な硬さを有することから、摺動部材１の摺動層３の耐摩耗性が高くなる。なお、界面側鋼相粒群６ＬＧの鋼相６Ｌは、組織中のフェライト相９の平均面積率が２０％以上であるため、摺動面側鋼相粒群６ＵＧの鋼相６Ｕに比べて硬さが低くなるが、摺動面に露出することはなく、摺動層３の耐摩耗性には影響しない。 On the other hand, in the steel phase 6U of the sliding surface side steel phase grain group 6UG arranged on the sliding surface side of the porous sintered layer 4, the average area ratio of the ferrite phase 9 in the structure is 10% or less. . When the sliding member 1 is used and the resin composition 5 coated on the surface of the porous sintered layer 4 is worn, the sliding surface side steel phase grain group disposed on the sliding surface side of the porous sintered layer 4 The 6UG granular steel phase 6U is exposed, but the steel phase 6U has sufficient hardness because the average area ratio of the ferrite phase 9 in the structure is 10% or less. The wear resistance of the sliding layer 3 of the moving member 1 is increased. Note that the steel phase 6L of the interface-side steel phase grain group 6LG has an average area ratio of the ferrite phase 9 in the structure of 20% or more, and therefore is harder than the steel phase 6U of the sliding surface side steel phase grain group 6UG. However, it is not exposed to the sliding surface and does not affect the wear resistance of the sliding layer 3.
次に、本実施形態に係る摺動部材１の作製方法について説明する。まず、炭素成分を０．８〜１．３質量％含有する炭素鋼のアトマイズ粉末とＮｉ−Ｐ合金のアトマイズ粉末との混合粉を準備する。この混合粉の準備時には、多孔質焼結層４のＮｉ−Ｐ合金相７となる成分を、Ｎｉ−Ｐ合金の粉末の形態で含ませる必要がある。また、Ｎｉ−Ｐ合金相７に、Ｂ、Ｓｉ、Ｃｒ、Ｆｅ、Ｓｎ、Ｃｕ等の選択成分を含有させる場合には、それら選択成分を含んだＮｉ−Ｐ合金のアトマイズ粉末と炭素鋼のアトマイズ粉末との混合粉を準備する必要がある。また、Ｎｉ−Ｐ合金の粉末は、炭素鋼の粉末（鋼相６）の平均粒径に対して１０〜３０％の平均粒径であるものを用いる必要がある。なお、混合粉におけるＮｉ−Ｐ合金の粉末の割合は、混合粉の１００質量部に対してＮｉ−Ｐ合金の粉末を５〜３０質量部とすることが好ましい。 Next, a method for producing the sliding member 1 according to this embodiment will be described. First, a mixed powder of an atomized powder of carbon steel containing 0.8 to 1.3% by mass of a carbon component and an atomized powder of a Ni-P alloy is prepared. When preparing the mixed powder, it is necessary to include a component that becomes the Ni-P alloy phase 7 of the porous sintered layer 4 in the form of a Ni-P alloy powder. In addition, when Ni-P alloy phase 7 contains selected components such as B, Si, Cr, Fe, Sn, Cu, etc., atomized powder of Ni-P alloy containing these selected components and atomization of carbon steel It is necessary to prepare a mixed powder with the powder. In addition, it is necessary to use Ni-P alloy powder having an average particle size of 10 to 30% with respect to the average particle size of the carbon steel powder (steel phase 6). The ratio of the Ni-P alloy powder in the mixed powder is preferably 5 to 30 parts by mass of the Ni-P alloy powder with respect to 100 parts by mass of the mixed powder.
そして、室温で、準備した混合粉を裏金上に散布し、粉末散布層を形成する。図６には、粉末散布層の焼結前の状態を示す。図６に示すように、粉末散布層中では、炭素鋼の粉末６ｐ（鋼相６）は、裏金層２の表面に複数個（図６では２個）積層されている。Ｎｉ−Ｐ合金の粉末７ｐは、炭素鋼の粉末６ｐ（鋼相６）の平均粒径に対して１０〜３０％の平均粒径であるものを用いると、炭素鋼の粉末６ｐ（鋼相６）どうしの間の隙間や炭素鋼の粉末６ｐ（鋼相６）と裏金層２の表面の間の隙間に多く存在するようになり、多孔質焼結層４の表面となる粉末散布層の表面付近では、粉末散布層の内部に比べてＮｉ―Ｐ合金の粉末７ｐが少なくなる。これは、混合粉を裏金層２の表面に散布している際に、粉末散布層の表面付近に散布されたＮｉ−Ｐ合金の粉末７ｐが、重力や散布時の振動の影響を受けて炭素鋼の粉末６ｐ（鋼相６）どうしの間の隙間を通り、裏金層２の表面との界面側へ向かって流動しやいように、炭素鋼の粉末６ｐの平均粒径とＮｉ−Ｐ合金の粉末７ｐの平均粒径とを選択しているからである。 And the prepared mixed powder is spread | dispersed on a back metal at room temperature, and a powder spreading layer is formed. In FIG. 6, the state before sintering of a powder spreading layer is shown. As shown in FIG. 6, a plurality (two in FIG. 6) of carbon steel powder 6 p (steel phase 6) are laminated on the surface of the back metal layer 2 in the powder spreading layer. When the Ni-P alloy powder 7p is 10-30% of the average particle diameter of the carbon steel powder 6p (steel phase 6), the carbon steel powder 6p (steel phase 6) is used. ) The surface of the powder-spreading layer that is present in the gaps between the carbon steel powder 6p (steel phase 6) and the surface of the back metal layer 2 and becomes the surface of the porous sintered layer 4 In the vicinity, the Ni-P alloy powder 7p is smaller than the inside of the powder spray layer. This is because when the mixed powder is dispersed on the surface of the backing metal layer 2, the Ni-P alloy powder 7 p dispersed near the surface of the powder dispersion layer is affected by gravity and vibration during dispersion. The average particle size of the carbon steel powder 6p and the Ni-P alloy so that the steel powder 6p (steel phase 6) flows easily through the gap between the steel powder 6p and toward the interface with the surface of the back metal layer 2. This is because the average particle size of the powder 7p is selected.
次に、粉末散布層を加圧することなく焼結炉を用いて、９３０〜１０００℃の還元雰囲気中で焼結する。なお、裏金層２は、従来から一般的な炭素鋼、オーステナイト系ステンレス鋼、フェライト系ステンレス鋼、Ｎｉ合金等の板や条を用いることができるが、これらに限定されないで他の組成の金属の裏金を用いてもよい。焼結時において、昇温途中の８８０℃になると、９〜１３質量％のＰと残部Ｎｉの組成からなるＮｉ−Ｐ合金の粒が溶融を始める。その液相は、炭素鋼（鋼相６）の粒どうしや、炭素鋼（鋼相６）の粒と裏金層２の表面との間で流動し、裏金層２の表面上に多孔質焼結層４の形成が開始される。９〜１３質量％のＰと残部Ｎｉ の組成からなるＮｉ−Ｐ合金の粒は、９５０℃で完全に液相となる。なお、Ｐの含有量範囲を少なくした１０〜１２質量％のＰと残部Ｎｉの組成からなるＮｉ−Ｐ合金の粒は、９３０℃で完全に液相となる。 Next, it sinters in a reducing atmosphere of 930-1000 degreeC using a sintering furnace, without pressurizing a powder spreading layer. The back metal layer 2 may be a plate or strip made of carbon steel, austenitic stainless steel, ferritic stainless steel, Ni alloy or the like, which is conventionally used, but is not limited to these and is made of a metal having another composition. A backing metal may be used. At the time of sintering, when the temperature reaches 880 ° C. during the temperature increase, Ni—P alloy grains having a composition of 9 to 13% by mass of P and the balance Ni begin to melt. The liquid phase flows between the grains of carbon steel (steel phase 6) or between the grains of carbon steel (steel phase 6) and the surface of the back metal layer 2, and is porously sintered on the surface of the back metal layer 2. Formation of layer 4 is started. The Ni—P alloy grains composed of 9 to 13% by mass of P and the balance Ni 2 are completely in a liquid phase at 950 ° C. In addition, the grain of Ni-P alloy which consists of composition of 10-12 mass% P which reduced the content range of P, and remainder Ni becomes completely a liquid phase at 930 ° C.
焼結温度は、Ｎｉ−Ｐ合金の粒が、完全に溶融する温度以上に設定されている。また、Ｎｉ−Ｐ合金の組成は、後述するが、炭素鋼（鋼相６）の組織が完全オーステナイト相となる温度（Ａ３変態点）以上で、完全に溶融する組成になされている。 The sintering temperature is set to be equal to or higher than the temperature at which the Ni—P alloy grains are completely melted. Although the composition of the Ni-P alloy will be described later, it is a composition that completely melts at a temperature (A3 transformation point) or higher at which the structure of the carbon steel (steel phase 6) becomes a complete austenite phase.
炭素成分を０．８〜１．３質量％含有する炭素鋼の焼結前の組織は、パーライト相とセメンタイト相との混合相１０とからなる組織であるが、焼結時の昇温過程で７２７℃（Ａ１変態点）になると、これら組織は、オーステナイト相への変態を始め、９００℃では完全にオーステナイト相からなる組織となる。このオーステナイト相は、パーライト相やセメンタイト相よりもＦｅ原子間の隙間（距離）が大きくなるので、多孔質焼結層４におけるＮｉ−Ｐ合金相７のＮｉ原子が、この隙間に侵入する拡散が起こり易い状態となる。上記したように、Ｎｉ−Ｐ合金の組成は、鋼相６の組織が完全オーステナイト相となる温度（Ａ３変態点）以上で、完全に溶融する組成になされており、焼結温度は、Ｎｉ−Ｐ合金の粒が、完全に溶融する温度以上に設定されている。これは、液相状態のＮｉ−Ｐ合金相７中のＮｉ原子は、固相状態のＮｉ−Ｐ合金相７中のＮｉ原子よりも、鋼相６の表面におけるオーステナイト相中への拡散が起こり易いからである。 The structure before the sintering of the carbon steel containing 0.8 to 1.3% by mass of the carbon component is a structure composed of the mixed phase 10 of the pearlite phase and the cementite phase. At 727 ° C. (A1 transformation point), these structures begin to transform into an austenite phase, and at 900 ° C., the structure is completely composed of an austenite phase. Since this austenite phase has a larger gap (distance) between Fe atoms than the pearlite phase and cementite phase, the diffusion of Ni atoms in the Ni-P alloy phase 7 in the porous sintered layer 4 into this gap is prevented. It is easy to happen. As described above, the composition of the Ni-P alloy is such that the steel phase 6 is completely melted at a temperature higher than the temperature at which the structure of the steel phase 6 becomes a complete austenite phase (A3 transformation point). The temperature is set to be equal to or higher than the temperature at which the P alloy grains completely melt. This is because the Ni atoms in the Ni-P alloy phase 7 in the liquid phase state diffuse into the austenite phase on the surface of the steel phase 6 rather than the Ni atoms in the Ni-P alloy phase 7 in the solid phase state. It is easy.
なお、Ｎｉ原子の拡散は、鋼相６とＮｉ−Ｐ合金相７との接触部のみで起こるのではなく、Ｎｉ原子は、この接触部から鋼相６とＮｉ−Ｐ合金相７とが直接、接触しない部分である鋼相６の表面（摺動層３の樹脂組成物５と接することになる鋼相６の表面）へも拡散する。 Note that the diffusion of Ni atoms does not occur only at the contact portion between the steel phase 6 and the Ni—P alloy phase 7, but the Ni atom directly passes between the steel phase 6 and the Ni—P alloy phase 7 from this contact portion. It also diffuses to the surface of the steel phase 6 that is not in contact (the surface of the steel phase 6 that will be in contact with the resin composition 5 of the sliding layer 3).
焼結時、Ｎｉ−Ｐ合金が完全に液相状態となり、且つ、鋼相６が完全オーステナイト組織の状態となることが組み合わさって、鋼相６の表面にＮｉ原子が拡散する。このＮｉ原子は、オーステナイト相に固溶される結果、オーステナイト相のＦｅ原子間の隙間に固溶されていた炭素原子が、鋼相６の内部側（粒の中心部側）へ追い出されるように拡散する。なお、液相状態にあったＮｉ原子は、鋼相６の表面におけるオーステナイト相へ拡散し、固溶されるのと同時に固相となるので、Ｎｉ原子が鋼相６の極表面付近にしか拡散しない。 When sintering, the Ni—P alloy is completely in a liquid phase state and the steel phase 6 is in a complete austenite structure state, and Ni atoms diffuse on the surface of the steel phase 6. As a result of the Ni atoms being dissolved in the austenite phase, the carbon atoms dissolved in the gaps between the Fe atoms in the austenite phase are driven out to the inside of the steel phase 6 (the center of the grain). Spread. The Ni atoms in the liquid phase state diffuse into the austenite phase on the surface of the steel phase 6 and become a solid phase at the same time as being dissolved, so that the Ni atoms diffuse only near the pole surface of the steel phase 6. do not do.
焼結後の冷却過程で７２７℃（Ａ１変態点）以下になると、オーステナイト相であったが鋼相６の組織は、フェライト相９と、パーライト相とセメンタイト相の混合相１０とからなる組織となる。鋼相６の組織中にフェライト相が現れるのは、前記したように鋼相６の組織がオーステナイト相であったときに、Ｎｉ原子が拡散して炭素原子の濃度が低くなった部位が鋼相６のオーステナイト相組織中に部分的に形成され、この炭素原子の濃度が低くなった部位のオーステナイト相が、冷却過程で７２７℃（Ａ１変態点）以下になると、フェライト相とパーライト相に変態したと考える。以上の機構により、鋼相６は、炭素成分の含有量が０．８質量％〜１．３質量％である過共析鋼（通常は、パーライト相とセメンタイト相とからなる組織）を用いるが、焼結後の組織は、フェライト相９と、パーライト相とセメンタイト相との混合相１０と、からなる組織となる。 When the temperature was 727 ° C. (A1 transformation point) or lower in the cooling process after sintering, the structure of the steel phase 6 was an austenite phase, but the structure consisting of a ferrite phase 9 and a mixed phase 10 of a pearlite phase and a cementite phase Become. The ferrite phase appears in the structure of the steel phase 6 because, as described above, when the structure of the steel phase 6 is the austenite phase, the Ni atom diffuses and the carbon atom concentration is lowered. When the austenite phase in the part of the austenite phase structure of No. 6 where the carbon atom concentration is low becomes 727 ° C. (A1 transformation point) or less during the cooling process, it transforms into a ferrite phase and a pearlite phase. I think. By the above mechanism, the steel phase 6 uses hypereutectoid steel (usually a structure composed of a pearlite phase and a cementite phase) having a carbon component content of 0.8 mass% to 1.3 mass%. The structure after sintering is a structure comprising a ferrite phase 9 and a mixed phase 10 of a pearlite phase and a cementite phase.
また、図６に示すように、焼結前の粉末散布層の表面側では、焼結後にＮｉ−Ｐ合金相７となるＮｉ−Ｐ合金の粉末７ｐの割合を少なくすることで、焼結中に、炭素鋼の粉末６ｐ（鋼相６）に対するＮｉ−Ｐ合金中のＮｉ原子の拡散が、粉末散布層の表面側に積層された炭素鋼の粉末６ｐ（鋼相６Ｕ）に対しては起き難くなり、粉末散布層の裏金層３との界面側に積層された炭素鋼の粉末６ｐ（鋼相６Ｌ）に対しては起きやすくなっている。このため、焼結後の多孔質焼結層４では、断面視において複数個積層された鋼相６のうち、多孔質焼結層４の摺動面側に配置された摺動面側鋼相粒群６ＵＧの鋼相６Ｕは、組織中のフェライト相９の平均面積率が１０％以下と少なくなるのに対し、多孔質焼結層４の裏金層２との界面側に配置された界面側鋼相粒群６ＬＧの鋼相６Ｌは、組織中のフェライト相９の平均面積率が２０％以上と多くなっている。 Further, as shown in FIG. 6, on the surface side of the powder spreading layer before sintering, the ratio of Ni-P alloy powder 7p that becomes Ni-P alloy phase 7 after sintering is reduced, so that sintering is in progress. Furthermore, the diffusion of Ni atoms in the Ni-P alloy with respect to the carbon steel powder 6p (steel phase 6) occurs with respect to the carbon steel powder 6p (steel phase 6U) laminated on the surface side of the powder spreading layer. It becomes difficult to occur with respect to the carbon steel powder 6p (steel phase 6L) laminated on the interface side with the back metal layer 3 of the powder spreading layer. For this reason, in the sintered porous layer 4 after sintering, among the steel phases 6 laminated in cross-section, the sliding surface side steel phase disposed on the sliding surface side of the porous sintered layer 4 The steel phase 6U of the grain group 6UG has an average area ratio of the ferrite phase 9 in the structure as low as 10% or less, whereas the interface side disposed on the interface side with the back metal layer 2 of the porous sintered layer 4 In the steel phase 6L of the steel phase grain group 6LG, the average area ratio of the ferrite phase 9 in the structure is as high as 20% or more.
また、多孔質焼結層４の摺動面側に配置された摺動面側鋼相粒群６ＵＧの鋼相６Ｕは、多孔質焼結層４の裏金層２との界面側に配置された界面側鋼相粒群６ＬＧの鋼相６Ｌに比べて拡散するＮｉ原子の量が少ないが、特に、鋼相６Ｕの粒の表面のうち摺動面側の表面には、Ｎｉ原子が拡散しないか、僅かに拡散する程度である。また、多孔質焼結層４の摺動面側に配置された鋼相６Ｕは、粒の表面のうち摺動面側の表面がＮｉ−Ｐ合金相７により覆われないようにすることで、多孔質焼結層４の摺動面側の表面を、粒状の鋼相６Ｕの表面によって形成することができる。 Further, the steel phase 6U of the sliding surface side steel phase grain group 6UG disposed on the sliding surface side of the porous sintered layer 4 is disposed on the interface side of the porous sintered layer 4 with the back metal layer 2. The amount of Ni atoms diffusing is smaller than that of the steel phase 6L of the interface side steel phase grain group 6LG. In particular, is the Ni atom not diffusing on the surface on the sliding surface side of the surface of the steel phase 6U grains? , To a slight extent. Further, the steel phase 6U disposed on the sliding surface side of the porous sintered layer 4 is such that the surface on the sliding surface side of the grain surface is not covered with the Ni-P alloy phase 7, The surface on the sliding surface side of the porous sintered layer 4 can be formed by the surface of the granular steel phase 6U.
また、界面側鋼相粒群６ＬＧの鋼相６Ｌとして、粒の表面でのフェライト相９の面積率が５０％以上であるものが、界面側鋼相粒群６ＬＧの鋼相６Ｌの全体に対する体積割合で５０％以上とする場合には、段落００４０に記載した混合粉の準備にて、炭素鋼の粉末（鋼相６）として、本発明範囲の中では炭素成分が少ない炭素鋼（例えば、炭素の含有量が０．８質量％〜１．１質量％である炭素鋼の粉末）を用いたり、多孔質焼結層４におけるＮｉ−Ｐ合金相７の割合を２５〜３０％質量部と多くしたり、あるいは、段落００４２に記載した焼結温度や加熱時間等の調整によって、鋼相６Ｌの粒の表面へのＮｉ原子が拡散する量が多くなるようにすれば、焼結後の鋼相６Ｌの組織中のフェライト相９の平均面積率を高くすることができる。 Further, as the steel phase 6L of the interface-side steel phase grain group 6LG, the area ratio of the ferrite phase 9 on the surface of the grain is 50% or more, and the volume relative to the entire steel phase 6L of the interface-side steel phase grain group 6LG. When the ratio is 50% or more, the carbon powder (steel phase 6) in the mixed powder preparation described in paragraph 0040 is used as a carbon steel powder (steel phase 6). Carbon steel powder having a content of 0.8 to 1.1% by mass), or the proportion of the Ni-P alloy phase 7 in the porous sintered layer 4 is as large as 25 to 30% by mass. Or by adjusting the sintering temperature and heating time described in paragraph 0042 so that the amount of Ni atoms diffusing into the surface of the grains of the steel phase 6L increases, the steel phase after sintering The average area ratio of the ferrite phase 9 in the 6 L structure can be increased.
上記のように裏金層２の表面上に多孔質焼結層４が形成された部材には、予め準備された樹脂組成物５（有機溶剤にて希釈してもよい）が、多孔質焼結層４の空孔部を充填し、多孔質焼結層４の表面を被覆するように含浸される。そして、この部材は、樹脂組成物５の乾燥、焼成のための加熱が施され、裏金層２の表面上に多孔質焼結層４と樹脂組成物５とからなる摺動層３が形成される。なお、樹脂組成物５としては、段落００２６に記載した樹脂組成物を用いることができる。また、本発明の摺動部材１は、予め、摺動面に切削加工や研削加工等を施して、摺動面に多孔質焼結層４の摺動面側鋼相粒群６ＵＧの鋼相６Ｕを露出させることもできる。、 As described above, the resin composition 5 (which may be diluted with an organic solvent) prepared in advance is porous sintered on the member having the porous sintered layer 4 formed on the surface of the back metal layer 2. The pores of the layer 4 are filled and impregnated so as to cover the surface of the porous sintered layer 4. The member is heated for drying and firing the resin composition 5, and the sliding layer 3 composed of the porous sintered layer 4 and the resin composition 5 is formed on the surface of the backing metal layer 2. The In addition, as the resin composition 5, the resin composition described in Paragraph 0026 can be used. In addition, the sliding member 1 of the present invention has a steel phase of the sliding surface side steel phase grain group 6UG of the porous sintered layer 4 on the sliding surface by cutting or grinding the sliding surface in advance. 6U can also be exposed. ,
なお、本実施形態の鋼相６には、アトマイズ法によって製造された粒状の炭素鋼の粉末を素材として用いることが望ましい。炭素鋼のアトマイズ粉末は、結晶組織に歪（原子空孔）が導入されている。この歪は、炭素鋼の結晶組織で本来、Ｆｅ原子が存在すべき部位にＦｅ原子が存在しない原子レベルの隙間が形成されている欠陥部である。焼結時の昇温過程で鋼相６（炭素鋼）における結晶の歪は、徐々に鋼相６の表面側へ移動して消滅するが、この歪と置き換わるようにＮｉ―Ｐ合金相７のＮｉ原子が、鋼相６の表面側の結晶中で歪があった部位へ拡散するようになる。一方、塊状の鋳鋼を機械粉砕した粉砕粉を用いた場合、粉砕粉は、アトマイズ粉末よりも結晶の歪が非常に少ないので、鋼相６の表面へのＮｉ原子の拡散が起こり難い。 In addition, it is desirable to use the powder of the granular carbon steel manufactured by the atomizing method as the raw material for the steel phase 6 of this embodiment. In the atomized powder of carbon steel, strain (atomic vacancies) is introduced into the crystal structure. This strain is a defect portion in which an atomic level gap in which Fe atoms do not exist is formed in a site where Fe atoms should exist in the crystal structure of carbon steel. The crystal distortion in the steel phase 6 (carbon steel) gradually moves to the surface side of the steel phase 6 and disappears during the temperature rising process during sintering, but the Ni-P alloy phase 7 is replaced by this strain. Ni atoms diffuse into the distorted portion in the crystal on the surface side of the steel phase 6. On the other hand, when the pulverized powder obtained by mechanically pulverizing the massive cast steel is used, the pulverized powder has much less crystal distortion than the atomized powder, so that the diffusion of Ni atoms to the surface of the steel phase 6 hardly occurs.
また、本実施形態では、上記のように炭素鋼のアトマイズ粉末とＮｉ−Ｐ合金のアトマイズ粉末との混合粉を用いたが、鋼相とＮｉ―Ｐ合金相との成分を予め合金化したＦｅ−Ｎｉ−Ｐ−Ｃ系合金のアトマイズ粉を用いた場合、多孔質焼結層はＦｅ−Ｎｉ合金相の素地に、遊離セメンタイト相（Ｆｅ３Ｃ）やＦｅ−Ｐ化合物相（Ｆｅ２Ｐ，Ｆｅ３Ｐ）やＮｉ―Ｐ化合物相（Ｎｉ３Ｐ）が混在した組織となり、多孔質焼結層の強度が低くなる。また、Ｎｉ粉末とＦｅ−Ｐ−Ｃ系合金粉末との混合粉を用いた場合、焼結時には、粉末組成のＮｉ成分の一部が液相化するのみで、液相の発生量が少なく、鋼相の表面へのＮｉ原子の拡散が殆ど起こらない。このため、鋼相の組織中にフェライト相形成されない。また、この液相はＮｉ３Ｐを主体とするので、焼結後のＮｉ相と鋼相との界面にＮｉ３Ｐ相（金属間化合物）が介在するように形成される。このＮｉ３Ｐ相は、硬質であるが脆く、多孔質焼結層の強度が低くなる。 In the present embodiment, as described above, the mixed powder of the atomized powder of carbon steel and the atomized powder of Ni—P alloy is used, but the Fe and alloyed in advance the components of the steel phase and the Ni—P alloy phase. When the atomized powder of -Ni-PC-based alloy is used, the porous sintered layer is formed on the basis of the Fe-Ni alloy phase, the free cementite phase (Fe 3 C) or the Fe-P compound phase (Fe 2 P, Fe 3 P) and Ni—P compound phase (Ni 3 P) are mixed, and the strength of the porous sintered layer is lowered. In addition, when using a mixed powder of Ni powder and Fe-PC-based alloy powder, only a part of the Ni component of the powder composition becomes liquid phase during sintering, and the amount of liquid phase generated is small. Almost no diffusion of Ni atoms to the surface of the steel phase occurs. For this reason, a ferrite phase is not formed in the structure of the steel phase. Further, since this liquid phase is mainly composed of Ni 3 P, it is formed so that the Ni 3 P phase (intermetallic compound) is interposed at the interface between the sintered Ni phase and the steel phase. This Ni 3 P phase is hard but brittle, and the strength of the porous sintered layer is lowered.
また、本実施形態における多孔質焼結層４のＮｉ−Ｐ合金相７の組成としてＢ、Ｓｉ、Ｃｒ、Ｆｅ、Ｓｎ、Ｃｕ等の選択成分を含有させる場合、前述したように、これら選択成分を含むＮｉ−Ｐ合金のアトマイズ粉末と炭素鋼のアトマイズ粉末との混合粉を準備し、裏金上で焼結する。この実施形態とは異なり、混合粉にＢ、Ｓｉ、Ｃｒ、Ｆｅ、Ｓｎ、Ｃｕ等の選択成分の単独の粉末、あるいは、これら選択成分どうしの合金の粉末の形態で含有させる場合、焼結後の多孔質焼結層４の粒状の鋼相６どうし、あるいは、鋼相６と裏金とを接合するバインダ部は、Ｎｉ−Ｐ合金相と、選択成分からなる相と、Ｎｉ−Ｐ合金相と選択成分の相との間に形成される反応相と、によって構成されるようになり、多孔質焼結層の強度が低くなる。特に、Ｓｎ成分は、前記混合粉に純Ｓｎ粉末、あるいは、Ｓｎ基合金の形態で含ませることは避けるべきである。純Ｓｎ、Ｓｎ基合金は融点が低く、焼結時の昇温過程における極初期の２３２℃程度で液相となるが、液相となったＳｎ原子と鋼相の表面のＦｅ原子とが反応し、Ｎｉ−Ｐ合金相と鋼相との界面にＦｅ２Ｓｎ相やＦｅ３Ｓｎ相（金属間化合物）が介在するように形成され、鋼相の組織中にフェライト相が形成されなくなる。さらに、このＦｅ２Ｓｎ相やＦｅ３Ｓｎ相は、硬質であるが脆く、Ｎｉ−Ｐ合金相と鋼相との接合が非常に弱くなる。 Further, when the selective component such as B, Si, Cr, Fe, Sn, Cu or the like is included as the composition of the Ni-P alloy phase 7 of the porous sintered layer 4 in the present embodiment, as described above, these selective components A mixed powder of an atomized powder of Ni-P alloy containing carbon and an atomized powder of carbon steel is prepared and sintered on a back metal. Unlike this embodiment, if the mixed powder is contained in the form of a single powder of a selected component such as B, Si, Cr, Fe, Sn, Cu, or a powder of an alloy of these selected components, after sintering The binder part which joins the granular steel phases 6 of the porous sintered layer 4 or the steel phase 6 and the back metal is composed of a Ni-P alloy phase, a phase composed of selected components, and a Ni-P alloy phase. It is comprised by the reaction phase formed between the phase of a selective component, and the intensity | strength of a porous sintered layer becomes low. In particular, it should be avoided that the Sn component is contained in the mixed powder in the form of pure Sn powder or Sn-based alloy. Pure Sn and Sn-based alloys have a low melting point and become a liquid phase at about 232 ° C. in the very initial stage of the temperature rising process during sintering, but the Sn atoms that have become liquid phase react with Fe atoms on the surface of the steel phase. However, the Fe 2 Sn phase or the Fe 3 Sn phase (intermetallic compound) is formed at the interface between the Ni—P alloy phase and the steel phase, and the ferrite phase is not formed in the structure of the steel phase. Furthermore, this Fe 2 Sn phase and Fe 3 Sn phase are hard but brittle, and the bonding between the Ni—P alloy phase and the steel phase becomes very weak.
また、本実施形態では、多孔質焼結層４における摺動面側鋼相粒群６ＵＧの鋼相６Ｕと界面側鋼相粒群６ＬＧの鋼相６Ｌとは、同じ組成の炭素鋼（過共析鋼）粉末を用いながらも、組織中のフェライト相９の割合を異なるようにしているので、摺動部材１を安価に製造することができる。これに対し、予め、炭素成分の含有量が異なり、組織中のフェライト相の割合が異なる２種類の組成の炭素鋼（亜共析鋼）粉末を、別々に、裏金層上に散布した場合には、多孔質焼結層の厚さの寸法精度が悪くなり、また、散布の工程の増加によって摺動部材が高価となる。 Further, in the present embodiment, the steel phase 6U of the sliding surface side steel phase grain group 6UG and the steel phase 6L of the interface side steel phase grain group 6LG in the porous sintered layer 4 are carbon steel having the same composition (hyperreactivity). Although the ratio of the ferrite phase 9 in the structure is made different while using powdered steel), the sliding member 1 can be manufactured at low cost. In contrast, when carbon steel (hyeposite steel) powders with two different compositions with different carbon component contents and different proportions of the ferrite phase in the structure are separately spread on the back metal layer, However, the dimensional accuracy of the thickness of the porous sintered layer is deteriorated, and the sliding member becomes expensive due to an increase in the spreading process.
１ 摺動部材
２ 裏金層
３ 摺動層
４ 多孔質焼結層
５ 樹脂組成物
６ 鋼相
６Ｕ 鋼相（摺動面側鋼相粒群の鋼相）
６Ｌ 鋼相（界面側鋼相粒群の鋼相）
６ＵＧ 摺動面側鋼相粒群
６ＬＧ 界面側鋼相粒群
７ Ｎｉ−Ｐ合金相
９ フェライト相
１０ パーライト相とセメンタイト相との混合相
DESCRIPTION OF SYMBOLS 1 Sliding member 2 Back metal layer 3 Sliding layer 4 Porous sintered layer 5 Resin composition 6 Steel phase 6U Steel phase (steel phase of sliding surface side steel phase grain group)
6L steel phase (steel phase of interfacial steel phase grain group)
6UG Sliding surface side steel phase grain group 6LG Interface side steel phase grain group 7 Ni-P alloy phase 9 Ferrite phase 10 Mixed phase of pearlite phase and cementite phase
Claims (7)
前記多孔質焼結層は、断面視において前記裏金層の表面に複数個積層された粒状の鋼相と、前記粒状の鋼相どうし及び前記粒状の鋼相と前記裏金層とをつなぐバインダとして機能するＮｉ−Ｐ合金相と、からなり、
前記粒状の鋼相は、炭素の含有量が０．８〜１．３質量％の炭素鋼であるとともに、組織がフェライト相と、パーライト相とセメンタイト相との混合相と、からなり、
前記断面視において複数個積層された粒状の鋼相のうち、前記多孔質焼結層の摺動面側に配置された摺動面側鋼相粒群では、前記粒状の鋼相の組織中の前記フェライト相の平均面積率が１０％以下である一方、前記多孔質焼結層の前記裏金層との界面側に配置された界面側鋼相粒群では、前記粒状の鋼相の組織中の前記フェライト相の平均面積率が２０％以上であることを特徴とする摺動部材。 A resin composition comprising a backing metal layer and a sliding layer, wherein the sliding layer is a porous sintered layer formed on the surface of the backing metal layer, and pores and surfaces of the porous sintered layer are impregnated and coated. In a sliding member made of
The porous sintered layer functions as a binder that connects a plurality of granular steel phases stacked on the surface of the back metal layer in cross-sectional view, the granular steel phases, and the granular steel phase and the back metal layer. And a Ni-P alloy phase
The granular steel phase is a carbon steel having a carbon content of 0.8 to 1.3% by mass, and the structure is composed of a ferrite phase and a mixed phase of a pearlite phase and a cementite phase,
Among the granular steel phases stacked in the cross-sectional view, in the sliding surface side steel phase grain group arranged on the sliding surface side of the porous sintered layer, the structure of the granular steel phase While the average area ratio of the ferrite phase is 10% or less, in the interface-side steel phase grain group arranged on the interface side with the back metal layer of the porous sintered layer, in the structure of the granular steel phase A sliding member, wherein an average area ratio of the ferrite phase is 20% or more.
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