JP6258121B2 - Sliding member - Google Patents
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- JP6258121B2 JP6258121B2 JP2014100876A JP2014100876A JP6258121B2 JP 6258121 B2 JP6258121 B2 JP 6258121B2 JP 2014100876 A JP2014100876 A JP 2014100876A JP 2014100876 A JP2014100876 A JP 2014100876A JP 6258121 B2 JP6258121 B2 JP 6258121B2
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- 229910000658 steel phase Inorganic materials 0.000 claims description 158
- 229910001562 pearlite Inorganic materials 0.000 claims description 147
- 239000010410 layer Substances 0.000 claims description 117
- 229910018104 Ni-P Inorganic materials 0.000 claims description 104
- 229910018536 Ni—P Inorganic materials 0.000 claims description 104
- 229910000905 alloy phase Inorganic materials 0.000 claims description 84
- 239000011342 resin composition Substances 0.000 claims description 51
- 229910000859 α-Fe Inorganic materials 0.000 claims description 43
- 229910052751 metal Inorganic materials 0.000 claims description 35
- 239000002184 metal Substances 0.000 claims description 35
- 239000012791 sliding layer Substances 0.000 claims description 32
- 229910001567 cementite Inorganic materials 0.000 claims description 29
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 claims description 27
- 239000000203 mixture Substances 0.000 claims description 27
- 229910000975 Carbon steel Inorganic materials 0.000 claims description 26
- 239000010962 carbon steel Substances 0.000 claims description 26
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 16
- 229910052799 carbon Inorganic materials 0.000 claims description 14
- 239000012535 impurity Substances 0.000 claims description 10
- 239000002245 particle Substances 0.000 claims description 10
- 239000011230 binding agent Substances 0.000 claims description 8
- 239000012071 phase Substances 0.000 description 234
- 239000000843 powder Substances 0.000 description 27
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 26
- 229910045601 alloy Inorganic materials 0.000 description 25
- 239000000956 alloy Substances 0.000 description 25
- 238000005245 sintering Methods 0.000 description 19
- 239000011135 tin Substances 0.000 description 17
- 125000004429 atom Chemical group 0.000 description 16
- 239000010949 copper Substances 0.000 description 15
- 239000007791 liquid phase Substances 0.000 description 15
- 229910052802 copper Inorganic materials 0.000 description 12
- 230000007797 corrosion Effects 0.000 description 11
- 238000005260 corrosion Methods 0.000 description 11
- 229910001566 austenite Inorganic materials 0.000 description 10
- 229910000831 Steel Inorganic materials 0.000 description 9
- 229910052742 iron Inorganic materials 0.000 description 9
- 239000000463 material Substances 0.000 description 9
- 239000011812 mixed powder Substances 0.000 description 9
- 239000011148 porous material Substances 0.000 description 9
- 239000010959 steel Substances 0.000 description 9
- 229910052718 tin Inorganic materials 0.000 description 8
- 239000000446 fuel Substances 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 6
- 229910052796 boron Inorganic materials 0.000 description 6
- 229910052804 chromium Inorganic materials 0.000 description 6
- 239000013078 crystal Substances 0.000 description 6
- 238000009792 diffusion process Methods 0.000 description 6
- 150000007524 organic acids Chemical class 0.000 description 6
- 229910052710 silicon Inorganic materials 0.000 description 6
- 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
- 229910000881 Cu alloy Inorganic materials 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 230000008018 melting Effects 0.000 description 5
- 238000007747 plating Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 238000010008 shearing Methods 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 239000011651 chromium Substances 0.000 description 4
- -1 polyethylene Polymers 0.000 description 4
- 230000009466 transformation Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000010304 firing Methods 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 229910000765 intermetallic Inorganic materials 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 230000000630 rising effect Effects 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 241000357293 Leptobrama muelleri Species 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 238000000889 atomisation Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000000945 filler Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000314 lubricant Substances 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 229920000098 polyolefin Polymers 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000007790 solid phase Substances 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 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
- 239000004642 Polyimide Substances 0.000 description 1
- 239000004734 Polyphenylene sulfide Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 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
- 238000001816 cooling Methods 0.000 description 1
- 150000001879 copper Chemical class 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000010191 image analysis Methods 0.000 description 1
- 238000003703 image analysis method Methods 0.000 description 1
- 150000002484 inorganic compounds Chemical class 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000010299 mechanically pulverizing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 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
- 238000002156 mixing Methods 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
- 235000005985 organic acids Nutrition 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920002312 polyamide-imide Polymers 0.000 description 1
- 229920002480 polybenzimidazole Polymers 0.000 description 1
- 229920002530 polyetherether ketone Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920006324 polyoxymethylene Polymers 0.000 description 1
- 229920000069 polyphenylene sulfide Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 238000003892 spreading 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
- 239000011800 void material Substances 0.000 description 1
Landscapes
- Sliding-Contact Bearings (AREA)
- Powder Metallurgy (AREA)
Description
本発明は、耐食性が高く、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 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.
また、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。しかしながら、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。 Moreover, in the multilayer sliding material of patent documents 4-6, since it has the structure of a steel back metal, intensity | strength is high. However, the porous sintered layer made of a copper alloy is corroded by an organic acid or sulfur component contained in the fuel or lubricating oil. Moreover, without providing a copper plating layer as in Patent Documents 4 to 6 on the surface of the steel backing metal, simply spraying and sintering carbon steel powder on the surface of the steel backing 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 circumstances, and the object of the present invention is to provide a sliding member having high corrosion resistance and strong bonding between the sliding layer resin composition and the porous sintered layer. It is to provide.
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、裏金層上に多孔質焼結層と樹脂組成物とからなる摺動層が設けられた摺動部材において、前記多孔質焼結層は、Ｎｉ−Ｐ合金相と粒状の鋼相とからなり、前記粒状の鋼相は、炭素の含有量が０．３〜１．３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、または、フェライト相とパーライト相とセメンタイト相とからなり、前記Ｎｉ−Ｐ合金相は、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しており、前記樹脂組成物または前記Ｎｉ−Ｐ合金相との界面となる前記粒状の鋼相の表面には、前記粒状の鋼相の組織が前記フェライト相とパーライト相とからなる場合、前記粒状の鋼相の中心部における組織中の前記パーライト相に対して前記パーライト相の割合が５０％以上少なくなっている低パーライト相部が形成されている一方、前記粒状の鋼相の組織が前記フェライト相とパーライト相とセメンタイト相とからなる場合、前記粒状の鋼相の中心部における組織中の前記パーライト相とセメンタイト相との混合相に対して前記パーライト相の割合が５０％以上少なくなっている低パーライト相部が形成されていることを特徴とする。 In order to achieve the above object, in the invention according to claim 1, in the sliding member in which the sliding layer comprising the porous sintered layer and the resin composition is provided on the back metal layer, the porous firing is performed. The layered layer is composed of a Ni-P alloy phase and a granular steel phase, and the granular steel phase is a carbon steel having a carbon content of 0.3 to 1.3% by mass, and the structure is a ferrite phase. And a pearlite phase, or a ferrite phase, a pearlite phase, and a cementite phase, and the Ni-P alloy phase functions as a binder that connects the granular steel phases and the granular steel phases to the backing metal layer. In addition, on the surface of the granular steel phase serving as an interface with the resin composition or the Ni-P alloy phase, when the structure of the granular steel phase is composed of the ferrite phase and the pearlite phase, Before in the structure in the center of the steel phase When a low pearlite phase portion in which the ratio of the pearlite phase to the pearlite phase is reduced by 50% or more is formed, the structure of the granular steel phase is composed of the ferrite phase, the pearlite phase, and the cementite phase. The low pearlite phase portion is formed in which the ratio of the pearlite phase is reduced by 50% or more with respect to the mixed phase of the pearlite phase and the cementite phase in the structure in the center of the granular steel phase. Features.
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、前記低パーライト相部には、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 in the low pearlite phase portion. .
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、前記低パーライト相部の厚さは、１〜３０μｍであることを特徴とする。 According to a fourth aspect of the present invention, in the sliding member according to any one of the first to third aspects, the low pearlite phase portion has a thickness of 1 to 30 μm.
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、前記低パーライト相部の表面における前記パーライト相の面積率は、０〜１０％であ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 area ratio of the said pearlite phase in the surface of the said low pearlite phase part is 0 to 10%. It is characterized by.
請求項６に係る発明においては、請求項１乃至請求項５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 6, in the sliding member in any one of Claim 1 thru | or 5, 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７に係る発明においては、請求項１乃至請求項５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 7, in the sliding member in any one of Claim 1 thru | or 5, 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 balance Ni and unavoidable impurities.
請求項８に係る発明においては、請求項１乃至請求項７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５〜４０質量部であることを特徴とする。 In the invention which concerns on Claim 8, in the sliding member in any one of Claim 1 thru | or 7, the ratio of the said Ni-P alloy phase in the said porous sintered layer is the said porous sintered layer. The said Ni-P alloy phase is 5-40 mass parts with respect to 100 mass parts of this, It is characterized by the above-mentioned.
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、Ｎｉ−Ｐ合金相と粒状の鋼相とからなり、有機酸や硫黄成分に対する耐食性が高い。多孔質焼結層のＮｉ−Ｐ合金相は、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している。また、鋼相は、炭素の含有量が０．３〜１．３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、または、フェライト相とパーライト相とセメンタイト相とからなるが、炭素の含有量が０．３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、摺動部材の強度が不十分となる。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、鋼相の低パーライト相部におけるパーライト相の割合が多くなってしまう。さらに、摺動層の樹脂組成物またはＮｉ−Ｐ合金相との界面となる粒状の鋼相の表面には、粒状の鋼相の組織がフェライト相とパーライト相とからなる場合、粒状の鋼相の中心部における組織中のパーライト相に対してパーライト相の割合が５０％以上少なくなっている低パーライト相部が形成されている一方、粒状の鋼相の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からなる場合、粒状の鋼相の中心部における組織中のパーライト相とセメンタイト相との混合相に対してパーライト相の割合が５０％以上少なくなっている低パーライト相部が形成されていることで、摺動層の樹脂組成物と粒状の鋼相の低パーライト相部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合金相と低パーライト相部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。なお、粒状の鋼相の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からなる場合でも、低パーライト相部の組織は、フェライト相とパーライト相とからなり、セメンタイト相（パーライト相を構成するセメンタイトは除く）は含まれていない。また、粒状の鋼相の組織がフェライト相とパーライト相とからなる場合、低パーライト相部の組織は、フェライト相の単相となる場合がある。 In the invention which concerns on Claim 1, the porous sintered layer which comprises a sliding layer consists of a Ni-P alloy phase and a granular steel phase, and has high corrosion resistance with respect to an organic acid and a sulfur component. The Ni-P alloy phase of the porous sintered layer functions as a binder for connecting the granular steel phases and the granular steel phase to the back metal layer. The steel phase is a carbon steel having a carbon content of 0.3 to 1.3% by mass, and the structure is composed of a ferrite phase and a pearlite phase, or a ferrite phase, a pearlite phase, and a cementite phase. When carbon steel having a carbon content of less than 0.3% by mass is used, the strength of the porous sintered layer is low, and the strength of the sliding member is insufficient. On the other hand, when carbon steel having a carbon content exceeding 1.3% by mass is used, the proportion of the pearlite phase in the low pearlite phase portion of the steel phase is increased. Furthermore, when the structure of the granular steel phase is composed of a ferrite phase and a pearlite phase on the surface of the granular steel phase serving as an interface with the resin composition of the sliding layer or the Ni-P alloy phase, the granular steel phase A low pearlite phase is formed in which the ratio of the pearlite phase is 50% or less of the pearlite phase in the structure at the center of the steel, while the granular steel phase is composed of a ferrite phase, a pearlite phase, and a cementite phase. A low pearlite phase portion in which the ratio of the pearlite phase is reduced by 50% or more with respect to the mixed phase of the pearlite phase and the cementite phase in the structure in the center of the granular steel phase is formed. Thus, the difference in thermal expansion at the interface between the resin composition of the sliding layer and the low pearlite phase part of the granular steel phase is small, and shearing at the interface is less likely to occur. Granular steel Can be strongly bonded with, at the same time, the shear at the interface between the Ni-P alloy phase and a low pearlite phase portion becomes difficult to occur, it is possible to increase the strength of the porous sintered layer. Even when the structure of the granular steel phase is composed of a ferrite phase, a pearlite phase, and a cementite phase, the structure of the low pearlite phase portion is composed of a ferrite phase and a pearlite phase, and the cementite phase (the cementite constituting the pearlite phase is Excluding) is not included. Moreover, when the structure of the granular steel phase is composed of a ferrite phase and a pearlite phase, the structure of the low pearlite phase portion may be a single phase of the ferrite phase.
また、請求項２に係る発明のように、粒状の鋼相の平均粒径は、４５〜１８０μｍとすることで、多孔質焼結層には、樹脂組成物を含浸させるために好適な空孔が形成される。粒状の鋼相の平均粒径が４５μｍ未満であると、多孔質焼結層に形成される各空孔部のサイズが小さくなり、樹脂組成物を含浸させ難くなる。一方、粒状の鋼相の平均粒径が１８０μｍを超えると、粒状の鋼相の表面の一部に、低パーライト相部が形成されない場合がある。 Moreover, like the invention which concerns on Claim 2, the average particle diameter of a granular steel phase shall be 45-180 micrometers, and the void | hole suitable for making a porous sintered layer impregnate a resin composition Is formed. When the average particle size of the granular steel phase is less than 45 μm, the size of each pore formed in the porous sintered layer becomes small, and it becomes difficult to impregnate the resin composition. On the other hand, if the average particle size of the granular steel phase exceeds 180 μm, a low pearlite phase portion may not be formed on a part of the surface of the granular steel phase.
また、請求項３に係る発明のように、低パーライト相部には、Ｎｉ−Ｐ合金相のＮｉ成分が拡散していることで、摺動層の樹脂組成物あるいはＮｉ−Ｐ合金相との接合を強くすることができる。 Further, as in the invention according to claim 3, since the Ni component of the Ni-P alloy phase is diffused in the low pearlite phase portion, the resin composition of the sliding layer or the Ni-P alloy phase Bonding can be strengthened.
また、請求項４に係る発明のように、低パーライト相部の厚さは、１〜３０μｍの範囲とする。低パーライト相部の厚さが３０μｍ以下であれば、粒状の鋼相の強度に影響しない。一方、低パーライト相部の厚さが１μｍ未満であると、粒状の鋼相の表面の一部に、低パーライト相部が形成されない場合がある。 Moreover, like the invention which concerns on Claim 4, the thickness of a low pearlite phase part shall be the range of 1-30 micrometers. If the thickness of the low pearlite phase part is 30 μm or less, the strength of the granular steel phase is not affected. On the other hand, when the thickness of the low pearlite phase portion is less than 1 μm, the low pearlite phase portion may not be formed on a part of the surface of the granular steel phase.
また、請求項５に係る発明のように、低パーライト相部の表面におけるパーライト相の面積率は、０〜１０％とする。低パーライト相部の表面におけるパーライト相の面積率は、１０％以下であると、摺動層の樹脂組成物あるいはＮｉ−Ｐ合金相と粒状の鋼相との接合強度を高める効果が高くなる。 Further, as in the invention according to claim 5, the area ratio of the pearlite phase on the surface of the low pearlite phase portion is set to 0 to 10%. When the area ratio of the pearlite phase on the surface of the low pearlite phase is 10% or less, the effect of increasing the bonding strength between the resin composition of the sliding layer or the Ni-P alloy phase and the granular steel phase is enhanced.
また、請求項６に係る発明のように、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で、Ｎｉ−Ｐ合金の融点が低くなる組成範囲とすることができる。なお、Ｎｉ−Ｐ合金相の組成は、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。裏金層上に多孔質焼結層を焼結するときの昇温過程では、多孔質焼結層のＮｉ−Ｐ合金相成分の全てを液相化させて、Ｎｉ成分を粒状の鋼相の表面に拡散させる。このＮｉ成分の粒状の鋼相の表面への拡散は、粒状の鋼相の表面への低パーライト相部の形成に関係している。Ｎｉ−Ｐ合金相の組成において、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成分が粒状の鋼相の表面に拡散し難くなり、粒状の鋼相の表面に低パーライト相部が形成され難くなる。 Further, as in the invention according to claim 6, the composition of the Ni-P alloy phase is composed of 9 to 13% by mass of P, the balance Ni and inevitable impurities, so that the melting point of the Ni-P alloy is lowered. It can be. In addition, as for the composition of a Ni-P alloy phase, it is more desirable to consist of 10-12 mass% P, remainder Ni, and an unavoidable impurity. In the temperature rising process when the porous sintered layer is sintered on the back metal layer, all the Ni-P alloy phase components of the porous sintered layer are made into a liquid phase, and the Ni component is converted into the surface of the granular steel phase. To diffuse. The diffusion of the Ni component to the surface of the granular steel phase is related to the formation of a low pearlite phase portion on the surface of the granular steel phase. In the composition of the Ni—P alloy phase, when the P content is less than 9 mass% or exceeds 13 mass%, the melting point of the Ni—P alloy becomes high. This reduces the amount of Ni-P alloy liquid phase generated during sintering, makes it difficult for the Ni component to diffuse to the surface of the granular steel phase, and forms a low pearlite phase on the surface of the granular steel phase. It becomes difficult.
また、請求項７に係る発明のように、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とすることができる。Ｐの含有量の範囲は、前記した通りであるが、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ら選択される１種以上を含有させて、Ｎｉ−Ｐ合金相の強度を調整してもよい。このようにＮｉ−Ｐ合金相は、これらの選択成分を含有しても、粒状の鋼相の表面への低パーライト相部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合金相に含有させる場合、Ｎｉ−Ｐ合金相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％以下とする必要がある。 Moreover, like the invention which concerns on Claim 7, the composition of a Ni-P alloy phase is 9-13 mass% P, 1-4 mass% B as a selective component, 1-12 mass% Si, It contains at least one selected from -12 mass% Cr, 1-3 mass% Fe, 0.5-5 mass% Sn, 0.5-5 mass% Cu, and the balance Ni and inevitable impurities It can be. The range of the content of P is as described above, but 1 to 4% by mass of B, 1 to 12% by mass of Si, 1 to 12% by mass of Cr, 1 to 3% by mass of Fe, as selective components, One or more selected from 0.5 to 5% by mass of Sn and 0.5 to 5% by mass of Cu may be included to adjust the strength of the Ni-P alloy phase. Thus, even if the Ni-P alloy phase contains these selective components, it does not affect the formation of the low pearlite phase portion on the surface of the granular steel phase. When the Cu component is included in the Ni-P alloy phase among the selected components, the content needs to be 5% by mass or less so as not to affect the corrosion resistance of the Ni-P alloy phase. .
また、請求項８に係る発明のように、多孔質焼結層におけるＮｉ−Ｐ合金相の割合は、多孔質焼結層の１００質量部に対してＮｉ−Ｐ合金相を５〜４０質量部とする。Ｎｉ−Ｐ合金相は、粒状の鋼相どうし及び粒状の鋼相と裏金層の表面とをつなぐバインダとして機能している。Ｎｉ−Ｐ合金相の割合が５質量部未満であると、多孔質焼結層の強度や、多孔質焼結層と裏金層との接合が不十分となる。一方、Ｎｉ−Ｐ合金相の割合が４０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、多孔質焼結層の空孔率が小さくなりすぎる。 As in the invention according to claim 8, the proportion of the Ni-P alloy phase in the porous sintered layer is 5 to 40 parts by mass of the Ni-P alloy phase with respect to 100 parts by mass of the porous sintered layer. And The Ni-P alloy phase functions as a binder that connects the granular steel phases and the granular steel phase to the surface of the back metal layer. When the proportion of the Ni-P alloy phase is less than 5 parts by mass, the strength of the porous sintered layer and the bonding between the porous sintered layer and the back metal layer become insufficient. On the other hand, if the proportion of the Ni-P alloy phase exceeds 40 parts by mass, the portion to be vacant is filled with the liquid phase of the Ni-P alloy during sintering. The rate is too small.
本実施形態に係る摺動部材１について、図１乃至図２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、粒状の鋼相６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 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 6.
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なっている。また、図１に示すように、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、全ての鋼相６の粒がＮｉ−Ｐ合金相７により覆われていてもよい。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. The Ni—P alloy phase 7 is 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. Further, as shown in FIG. 1, the grains of the steel phase 6, or the grains of the steel phase 6 and the surface of the back metal layer 2 are joined via a 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 grains of the steel phase 6 are covered with the Ni—P alloy phase 7. It may be. 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%.
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の表面への低パーライト相部８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の表面に低パーライト相部８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 low pearlite phase portion 8 on the surface 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. Thereby, the amount of generation of the liquid phase of the Ni—P alloy is reduced during sintering, the Ni component is difficult to diffuse to the surface of the steel phase 6, and the low pearlite phase portion 8 is not easily formed on the surface of the steel phase 6. Become.
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種以上を含有させた組成であってもよい。なお、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 composition may contain one or more selected from 0.5 to 5% by mass of Sn and 0.5 to 5% by mass of Cu. Note that the Ni-P alloy phase 7 containing these selective components preferably has a structure in which the Ni base portion is a solid solution of P, which is an essential component, and B, Si, Cr, Fe, Sn, and Cu, which are optional 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５〜４０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４０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。 The ratio of the Ni—P alloy phase 7 in the porous sintered layer 4 is 5 to 40 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 40 parts by mass, the portion to be vacant is filled with the Ni-P alloy during sintering, so the porosity of the porous sintered layer 4 Is too small.
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、鋼相６の表面の一部に、低パーライト相部８が形成されない場合がある。 The granular steel phase 6 in the porous sintered layer 4 may have an average particle diameter of 45 to 180 μm. 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 low pearlite phase portion 8 may not be formed on a part of the surface of the steel phase 6.
また、粒状の鋼相６の組成は、炭素成分を０．３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亜共析鋼、共析鋼、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１０、または、フェライト相９とパーライト相１０とセメンタイト相とからなるが、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 0.3% by mass to 1.3% by mass of a carbon component, and is generally a granular hypoeutectoid steel, eutectoid steel by an atomization method, Hypereutectoid steel 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. The structure of the steel phase 6 is composed of a ferrite phase 9 and a pearlite phase 10, or a ferrite phase 9, a pearlite phase 10 and a cementite phase. It is permissible to contain a precipitate phase that cannot be detected even if it is conducted. 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.
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 FIG. 2, 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、鋼相６の組織は、フェライト相９とパーライト相１０とからなる。鋼相６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６におけるパーライト相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。このパーライト相１０は、フェライト相９よりも炭素成分の量が多い。そして、図２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６の表面には、鋼相６の粒の中心部における組織中のパーライト相１０に対してパーライト相１０の割合が５０％以上少なくなっている低パーライト相部８が形成される。この低パーライト相部８は、図２に示す鋼相６の粒の断面組織において、鋼相６の粒の表面に隣接するフェライト相６の結晶を主体として形成される環状の層部分である。なお、多孔質焼結層４を構成する粒状の鋼相６のうち、粒の個数割合で２０％以下の個数の鋼相６（あるいは、鋼相６の全体積に対して２０体積％以下）は、粒の表面に低パーライ相部８が形成されていないことは許容される。 As shown in FIG. 2, the structure of the steel phase 6 is composed of a ferrite phase 9 and a pearlite phase 10. The ferrite phase 9 in the steel phase 6 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 pearlite phase 10 in the steel phase 6 is a lamellar structure phase in which a ferrite phase and a cementite phase (Fe 3 C) that is an iron carbide are alternately formed in a thin plate shape. The pearlite phase 10 has a larger amount of carbon component than the ferrite phase 9. Then, as shown in FIG. 2, the surface of the steel phase 6 serving as an interface with the resin composition 5 or the Ni—P alloy phase 7 is in relation to the pearlite phase 10 in the structure at the center of the grain of the steel phase 6. Thus, the low pearlite phase portion 8 in which the ratio of the pearlite phase 10 is reduced by 50% or more is formed. The low pearlite phase portion 8 is an annular layer portion formed mainly of crystals of the ferrite phase 6 adjacent to the surface of the grain of the steel phase 6 in the cross-sectional structure of the grain of the steel phase 6 shown in FIG. In addition, among the granular steel phases 6 constituting the porous sintered layer 4, the number of the steel phases 6 is 20% or less in terms of the number of grains (or 20% by volume or less based on the total volume of the steel phases 6). It is permissible that the low pearly phase portion 8 is not formed on the surface of the grains.
本実施形態では、電子顕微鏡を用いて摺動部材１の厚さ方向に平行な方向に切断された断面組織において、複数個（例えば５個）の鋼相６の粒の中心部付近、及び、摺動層３の樹脂組成物５あるいはＮｉ−Ｐ合金相７との界面となる鋼相６の表面付近をそれぞれ倍率１０００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、組織中のパーライト相１０の面積率を測定した。そして、鋼相６の粒の中心部における組織中のパーライト相１０に対して、鋼相６の粒の表面付近における組織中のパーライト相１０の割合（面析率）が５０％以上少なくなっていることで、鋼相６の粒の表面に低パーライト相部８が形成されていることが確認できる。なお、鋼相６の粒の中心部付近におけるパーライト相１０の面積率の観察部は、厳密な意味での鋼相６の粒の中心部位置でなくてもよい。これは、鋼相６のの中心部位置から低パーライト相部８までの間の組織が、実質的にほぼ同じ組織（同じパーライト相１０の面積率）になっているからである。 In the present embodiment, in the cross-sectional structure cut in the direction parallel to the thickness direction of the sliding member 1 using an electron microscope, the vicinity of the center of a plurality of (for example, five) steel phase 6 grains, and An electronic image is taken at a magnification of 1000 times around the surface of the steel phase 6 that becomes the interface with the resin composition 5 of the sliding layer 3 or the Ni-P alloy phase 7, and the image is analyzed by a general image analysis technique (analysis). Software: Image-Pro Plus (Version 4.5); manufactured by Planetron Co., Ltd.) was used to measure the area ratio of the pearlite phase 10 in the tissue. And the ratio (surface fraction) of the pearlite phase 10 in the structure near the surface of the grain of the steel phase 6 is reduced by 50% or more with respect to the pearlite phase 10 in the structure at the center of the grain of the steel phase 6. It can be confirmed that the low pearlite phase portion 8 is formed on the surface of the grains of the steel phase 6. In addition, the observation part of the area ratio of the pearlite phase 10 in the vicinity of the center part of the grain of the steel phase 6 may not be the position of the center part of the grain of the steel phase 6 in a strict sense. This is because the structure between the center position of the steel phase 6 and the low pearlite phase part 8 has substantially the same structure (the area ratio of the same pearlite phase 10).
上記した低パーライト相部８の厚さは、摺動層３の樹脂組成物５あるいはＮｉ−Ｐ合金相７との界面から１〜３０μｍである。さらに、低パーライト相部８の厚さは、１〜１０μｍとすることが好ましい。また、低パーライト相部８の厚さは、鋼相６の平均粒径の２０％以下とすることが好ましい。低パーライト相部８の厚さが３０μｍ以下であれば、鋼相６の強度に影響しない。一方、低パーライト相部８の厚さが１μｍ未満であると、鋼相６の表面の一部に、低パーライト相部８が形成されない場合がある。 The thickness of the low pearlite phase portion 8 is 1 to 30 μm from the interface between the sliding layer 3 and the resin composition 5 or the Ni—P alloy phase 7. Furthermore, it is preferable that the thickness of the low pearlite phase part 8 shall be 1-10 micrometers. The thickness of the low pearlite phase portion 8 is preferably 20% or less of the average particle diameter of the steel phase 6. If the thickness of the low pearlite phase portion 8 is 30 μm or less, the strength of the steel phase 6 is not affected. On the other hand, if the thickness of the low pearlite phase portion 8 is less than 1 μm, the low pearlite phase portion 8 may not be formed on a part of the surface of the steel phase 6.
また、摺動層３の樹脂組成物５あるいはＮｉ−Ｐ合金相７との界面となる鋼相６の低パーライト相部８には、多孔質焼結層４におけるＮｉ−Ｐ合金相７から拡散したＮｉ成分が含まれている。このＮｉ成分は、低パーライト相部８の表面付近のフェライト相９に固溶した形態で低パーライト相部８に含まれている。多孔質焼結層４のＮｉ−Ｐ合金相７から鋼相６の低パーライト相部８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）測定により低パーライト相部８に拡散したＮｉ成分が確認される。また、低パーライト相部８中のＮｉ成分は、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との界面となる低パーライト相部８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、低パーライト相部８には、Ｎｉ３Ｐ（金属間化合物）の相が形成されていない。 In addition, the low pearlite phase portion 8 of the steel phase 6 that becomes the interface with the resin composition 5 of the sliding layer 3 or the Ni—P alloy phase 7 diffuses from the Ni—P alloy phase 7 in the porous sintered layer 4. Ni component is contained. This Ni component is contained in the low pearlite phase portion 8 in the form of a solid solution in the ferrite phase 9 near the surface of the low pearlite phase portion 8. Although the Ni component diffused from the Ni-P alloy phase 7 of the porous sintered layer 4 to the low pearlite phase portion 8 of the steel phase 6 is extremely small, it is changed to the low pearlite phase portion 8 by EPMA (Electron Probe Microanalyzer) measurement. The diffused Ni component is confirmed. Further, the Ni component in the low pearlite phase portion 8 exists in the form of a solid solution in the ferrite phase 9, and the low pearlite phase portion 8 serving as an 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 toward the inside. Note that a phase of Ni 3 P (intermetallic compound) is not formed in the low pearlite phase portion 8.
また、鋼相６の低パーライト相部８の表面は、Ｎｉ成分の拡散により、特にパーライト相１０が少なくなっている。低パーライト相部８の表面におけるパーライト相１０の面積率は、摺動層３の樹脂組成物５あるいはＮｉ―Ｐ合金相７と鋼相６の低パーライト相部８との接合強度を高めるため、０〜１０％とすることが好ましい。なお、鋼相６の表面におけるパーライト相１０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の厚さ方向に平行な方向に切断された断面組織において、複数個（例えば５個）の鋼相６の粒を倍率１０００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、鋼相６の輪郭線の全長に対するパーライト相１０による輪郭線の長さの割合（鋼相６の外周である輪郭線のうちパーライト相１０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。 Further, the surface of the low pearlite phase portion 8 of the steel phase 6 is particularly reduced in the pearlite phase 10 due to the diffusion of the Ni component. The area ratio of the pearlite phase 10 on the surface of the low pearlite phase portion 8 is to increase the bonding strength between the resin composition 5 of the sliding layer 3 or the Ni—P alloy phase 7 and the low pearlite phase portion 8 of the steel phase 6. It is preferable to set it as 0 to 10%. Note that the area ratio of the pearlite phase 10 on the surface of the steel phase 6 cannot be directly measured, but a plurality of cross-sectional structures cut in a direction parallel to the thickness direction of the sliding member 1 using an electron microscope are used. An electronic image was taken of the steel phase 6 grains (for example, 5 pieces) at a magnification of 1000 times, and the image was analyzed by 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 pearlite phase 10 to the total length of the contour line of the steel phase 6 (the ratio of the length corresponding to the pearlite phase 10 in the contour line that is the outer periphery of the steel phase 6) It can be confirmed by measuring.
図３は、別実施形態の鋼相６の組織を示す拡大図である。鋼相６は、炭素成分の含有量が０．８質量％を超える過共析鋼の粉末を用いるときには、図３に示すように、鋼相６の粒の組織がフェライト相９とパーライト相１０とセメンタイト相とからなり、鋼相６の粒の表面付近にはフェライト相９とパーライト相１０とからなる低パーライト相部８が形成され、鋼相６の粒の中心部の組織が少量のフェライト相９、及びパーライト相とセメンタイト相との混合相１０Ａになる場合がある。この場合には、鋼相６の粒の中心部における組織中のパーライト相とセメンタイト相との混合相１０Ａに対して、鋼相６の粒の表面付近における組織中のパーライト相１０の割合（面積率）が５０％以上少なくなっていることで、鋼相６の表面に低パーライト相部８が形成されていることが確認できる。また、パーライト相とセメンタイト相との混合相１０Ａは、ベイナイト相、ソルバイト相、トールースタイト相を含んでいてもよい。 FIG. 3 is an enlarged view showing the structure of the steel phase 6 of another embodiment. When the steel phase 6 uses a hypereutectoid steel powder having a carbon component content exceeding 0.8% by mass, the grain structure of the steel phase 6 is composed of a ferrite phase 9 and a pearlite phase 10 as shown in FIG. And a cementite phase, a low pearlite phase portion 8 comprising a ferrite phase 9 and a pearlite phase 10 is formed near the surface of the grain of the steel phase 6, and the structure of the center portion of the grain of the steel phase 6 has a small amount of ferrite. In some cases, the phase 9 may be a mixed phase 10A of a pearlite phase and a cementite phase. In this case, the ratio (area) of the pearlite phase 10 in the structure near the surface of the grain of the steel phase 6 to the mixed phase 10A of the pearlite phase and the cementite phase in the structure at the center of the grain of the steel phase 6 Ratio) is reduced by 50% or more, it can be confirmed that the low pearlite phase portion 8 is formed on the surface of the steel phase 6. Further, the mixed phase 10A of the pearlite phase and the cementite phase may include a bainite phase, a sorbite phase, and a tallestite phase.
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４を参照して説明する。図４は、従来の裏金層１２上に組織がフェライト相とパーライト相とからなる炭素鋼（亜共析鋼）粉末を焼結した多孔質焼結層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、多孔質焼結層１４の表面（炭素鋼の表面）と内部とにおいてフェライト相やパーライト相の割合に差はなく、表面においてもパーライト相が多く形成されている。 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. 4 is a schematic view showing a sliding member 11 in which a porous sintered layer 14 in which a carbon steel (hyeutectoid steel) powder whose structure is composed of a ferrite phase and a pearlite phase is sintered is formed on a conventional back metal layer 12. FIG. The structure of the sintered porous layer 14 after sintering is such that there is no difference in the ratio of the ferrite phase and the pearlite phase between the surface of the porous sintered layer 14 (the surface of the carbon steel) and the inside, and the pearlite phase is also present on the surface. Many are formed.
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）において、パーライト相が多いと、摺動層１３の樹脂組成物１５との接合が弱くなる。図４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。 When the surface of the porous sintered layer 14 (the surface of the carbon steel) serving as an interface with the resin composition 15 of the sliding layer 13 has a large amount of pearlite phase, the bonding of the sliding layer 13 with the resin composition 15 is weak. Become. As shown in FIG. 4, 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におけるフェライト相とパーライト相とでは熱膨張係数が異なり、パーライト相は鉄炭化物であるセメンタイト（Ｆｅ３Ｃ）を含むために、フェライト相よりも熱膨張係数が小さい。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は、界面において不均一となる。そして、摺動層１３の樹脂組成物１５と多孔質焼結層１４のパーライト相との界面では、熱膨張量の差が大きく、その熱膨張量の差によるせん断応力によって微小せん断部が形成される。また、多孔質焼結層１４の表面におけるパーライト相の面積が多いほど、微小せん断が起こる面積が増加し、摺動層１３の樹脂組成物１５と多孔質焼結層１４のフェライト相との界面にも、このせん断が伝播すると考えられる。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の表面において、鋼相６の粒の内部に対してパーライト相１０の割合が５０％以上少なくなっている低パーライト相部８が形成されることで、そのような摺動層３の樹脂組成物５と多孔質焼結層６との界面でのせん断が起き難くなっている。また、Ｎｉ−Ｐ合金相７との界面となる鋼相６の表面において、鋼相６の粒の内部に対してパーライト相１０の割合が５０％以上少なくなっている低パーライト相部８が形成されることで、フェライト相９とパーライト相１０との熱膨張係数の違いに起因したＮｉ―Ｐ合金相７と鋼相６との界面でのせん断が起き難くなっている。 Specifically, the ferrite phase and the pearlite phase in the porous sintered layer 14 have different thermal expansion coefficients, and the pearlite phase contains cementite (Fe 3 C), which is an iron carbide. Is small. For this reason, when the temperature of the sliding member 11 rises, 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 becomes non-uniform at the interface. At the interface between the resin composition 15 of the sliding layer 13 and the pearlite phase of the porous sintered layer 14, the difference in thermal expansion is large, and a micro-shear portion is formed by shear stress due to the difference in thermal expansion. The Further, as the area of the pearlite phase on the surface of the porous sintered layer 14 increases, the area where micro shearing occurs increases, and the interface between the resin composition 15 of the sliding layer 13 and the ferrite phase of the porous sintered layer 14. Moreover, this shear is considered to propagate. On the other hand, in this embodiment, the pearlite phase 10 with respect to the inside of the grains of the steel phase 6 on the surface of the steel phase 6 of the porous sintered layer 4 that becomes the interface with the resin composition 5 of the sliding layer 3. By forming the low pearlite phase portion 8 in which the ratio is reduced by 50% or more, shearing at the interface between the resin composition 5 of the sliding layer 3 and the porous sintered layer 6 hardly occurs. It has become. Further, on the surface of the steel phase 6 that becomes the interface with the Ni-P alloy phase 7, a low pearlite phase portion 8 is formed in which the ratio of the pearlite phase 10 is reduced by 50% or more with respect to the inside of the grains of the steel phase 6. As a result, shearing at the interface between the Ni—P alloy phase 7 and the steel phase 6 due to the difference in thermal expansion coefficient between the ferrite phase 9 and the pearlite phase 10 is difficult to occur.
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０．３〜１．３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。そして、室温で、準備した混合粉を裏金上に散布した後、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。 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 0.3 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. And after spraying the prepared mixed powder on a back metal at room temperature, it sinters in a 930-1000 degreeC reducing atmosphere using a sintering furnace, without pressurizing a powder spreading layer. The back metal layer may be a plate or strip of conventional carbon steel, austenitic stainless steel, ferritic stainless steel, Ni alloy, etc., but is not limited to these, and metal back metal of other composition May be used.
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。 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０．３〜１．３質量％含有する炭素鋼の焼結前の組織は、フェライト相９とパーライト相１０とからなる組織、パーライト相１０からなる組織、あるいは、パーライト相１０とセメンタイト相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、フェライト相９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 sintering of carbon steel containing 0.3 to 1.3% by mass of carbon component is a structure composed of ferrite phase 9 and pearlite phase 10, a structure composed of pearlite phase 10, or pearlite phase 10 and cementite. When the temperature rises during sintering to 727 ° C. (A1 transformation point), these structures begin to transform into the austenite phase, and at 900 ° C., the structure is completely composed of the austenite phase. Become. Since the austenite phase has a larger gap (distance) between Fe atoms than the ferrite phase 9, the Ni atoms of the Ni—P alloy phase 7 in the porous sintered layer 4 are likely to diffuse into the gap. It becomes a state. 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、鋼相６の組織は、フェライト相９とパーライト相１０とからなる組織、パーライト相１０からなる組織、あるいは、フェライト相９とパーライト相１０とセメンタイト相とからなる組織となる。以上の機構により、鋼相６の粒の中心部付近では、炭素成分の含有量によって決まる通常のフェライト相９とパーライト相１０とからなる組織、パーライト相１０からなる組織、あるいは、フェライト相９とパーライト相１０とセメンタイト相とからなる組織（フェライト相９、及びパーライト相とセメンタイト相との混合相１０Ａからなる組織）となり、鋼相６の表面付近には、その中心部での組織中のパーライト相１０（中心部がパーライト相とセメンタイト相との混合相１０Ａからなる組織の場合には、その組織中のパーライト相とセメンタイト相との混合相１０Ａ）に対してパーライト相１０の割合が少なくなっている組織（鋼相６の極表面は、ほぼフェライト相９からなる組織）である低パーライト相部８が形成されると推定される。なお、Ｎｉ成分は、低パーライト相部８の表面付近のフェライト相９に固溶された状態で鋼相６に含まれている。 When it becomes 727 ° C. (A1 transformation point) or lower in the cooling process after sintering, the structure of the steel phase 6 is a structure composed of the ferrite phase 9 and the pearlite phase 10, a structure composed of the pearlite phase 10, or the ferrite phase 9 The structure consists of a pearlite phase 10 and a cementite phase. By the above mechanism, in the vicinity of the center part of the grain of the steel phase 6, the structure composed of the normal ferrite phase 9 and the pearlite phase 10 determined by the content of the carbon component, the structure composed of the pearlite phase 10, or the ferrite phase 9 and It becomes a structure composed of a pearlite phase 10 and a cementite phase (structure composed of a ferrite phase 9 and a mixed phase 10A of a pearlite phase and a cementite phase), and in the vicinity of the surface of the steel phase 6, the pearlite in the structure at the center thereof The ratio of the pearlite phase 10 is small with respect to the phase 10 (in the case where the center is a structure composed of a mixed phase 10A of a pearlite phase and a cementite phase, the mixed phase 10A of the pearlite phase and the cementite phase in the structure). It is presumed that a low pearlite phase portion 8 having a structure (the surface of the steel phase 6 is substantially composed of a ferrite phase 9) is formed. . The Ni component is contained in the steel phase 6 in a state of being dissolved in the ferrite phase 9 near the surface of the low pearlite phase portion 8.
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００３２に記載した樹脂組成物を用いることができる。 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 0032 can be used.
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、鋼相の表面には、パーライト相の割合が減少した低パーライト相部が形成されない。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, the low pearlite phase part in which the ratio of the pearlite phase decreased is not formed on the surface 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、鋼相の表面には低パーライト相部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. In addition, 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 low pearlite phase portion is not formed on the surface 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の鋼相６の表面に低パーライト相部８を形成しているが、予め、表面にＦｅめっき層やＮｉめっき層を形成した炭素鋼粉末を用いる場合には、摺動部材が高価となる。本実施形態は、このような炭素鋼粉末の表面へのめっき層の形成工程を省略し、多孔質焼結層４の焼結工程にて同時に鋼相６の低パーライト相部８の形成を行うので、摺動部材１を安価に製造することができる。 Moreover, in this embodiment, although the low pearlite phase part 8 is formed in the surface of the steel phase 6 of the porous sintered layer 4, the carbon steel powder which formed the Fe plating layer and Ni plating layer in the surface beforehand is used. When used, the sliding member becomes expensive. In the present embodiment, the step of forming the plating layer on the surface of the carbon steel powder is omitted, and the low pearlite phase portion 8 of the steel phase 6 is simultaneously formed in the sintering step of the porous sintered layer 4. Therefore, the sliding member 1 can be manufactured at low cost.
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
７ Ｎｉ−Ｐ合金相
８ 低パーライト相部
９ フェライト相
１０ パーライト相
１０Ａ 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 7 Ni-P alloy phase 8 Low pearlite phase part 9 Ferrite phase 10 Pearlite phase 10A Mixing of pearlite phase and cementite phase phase
Claims (8)
前記多孔質焼結層は、Ｎｉ−Ｐ合金相と粒状の鋼相とからなり、
前記粒状の鋼相は、炭素の含有量が０．３〜１．３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、または、フェライト相とパーライト相とセメンタイト相とからなり、
前記Ｎｉ−Ｐ合金相は、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しており、
前記樹脂組成物または前記Ｎｉ−Ｐ合金相との界面となる前記粒状の鋼相の表面には、
前記粒状の鋼相の組織が前記フェライト相とパーライト相とからなる場合、前記粒状の鋼相の中心部における組織中の前記パーライト相に対して前記パーライト相の割合が５０％以上少なくなっている低パーライト相部が形成されている一方、
前記粒状の鋼相の組織が前記フェライト相とパーライト相とセメンタイト相とからなる場合、前記粒状の鋼相の中心部における組織中の前記パーライト相とセメンタイト相との混合相に対して前記パーライト相の割合が５０％以上少なくなっている低パーライト相部が形成されていることを特徴とする摺動部材。 In the sliding member provided with the sliding layer composed of the porous sintered layer and the resin composition on the back metal layer,
The porous sintered layer comprises a Ni-P alloy phase and a granular steel phase,
The granular steel phase is a carbon steel having a carbon content of 0.3 to 1.3% by mass, and the structure is composed of a ferrite phase and a pearlite phase, or a ferrite phase, a pearlite phase, and a cementite phase,
The Ni-P alloy phase functions as a binder that connects the granular steel phases and the granular steel phases to the back metal layer,
On the surface of the granular steel phase that becomes an interface with the resin composition or the Ni-P alloy phase,
When the structure of the granular steel phase is composed of the ferrite phase and the pearlite phase, the ratio of the pearlite phase is reduced by 50% or more with respect to the pearlite phase in the structure at the center of the granular steel phase. While the low pearlite phase is formed,
When the structure of the granular steel phase is composed of the ferrite phase, the pearlite phase, and the cementite phase, the pearlite phase with respect to the mixed phase of the pearlite phase and the cementite phase in the structure at the center of the granular steel phase. A sliding member characterized in that a low pearlite phase portion is formed in which the ratio of is reduced by 50% or more.
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