Friction material

Abstract

A friction material having 40 mass % or more to 80 mass % or less of a matrix of at least one of a metal, an alloy, a metal compound and an intermetallic compound; 5 mass % or more to 30 mass % or less of solid particles of at least one of a carbide, a nitride, an oxide and a sulfide; and 5 mass % or more to 40 mass % or less of a lubricant wherein: the matrix comprises, as elements, at least, 20 mass % or more to 50 mass % or less of Fe, 0.05 mass % or more to 5.0 mass % or less of P, and 40 mass % or more to 75 mass % or less of Ni, based on a total amount of the matrix; and a content of Cu as an element is 15 mass % or less based on a total amount of the matrix.

Claims

1. A friction material comprising: 40 mass % or more to 80 mass % or less of a matrix of at least one kind selected from the group consisting of a metal, an alloy, a metal compound and an intermetallic compound; 5 mass % or more to 30 mass % or less of solid particles of at least one kind selected from the group consisting of a carbide, a nitride, an oxide and a sulfide of an element of at least one kind selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Mg and Si; and 5 mass % or more to 40 mass % or less of a lubricant of at least one kind selected from the group consisting of graphite, molybdenum disulfide, tungsten disulfide, boron nitride and calcium fluoride, wherein: the matrix comprises, as elements, at least, 20 mass % or more to 50 mass % or less of Fe, 0.05 mass % or more to 5.0 mass % or less of P, and 40 mass % or more to 75 mass % or less of Ni, based on a total amount of the matrix; and a content of Cu as an element is 15 mass % or less based on a total amount of the matrix.

2. The friction material according to claim 1, wherein a mass content ratio of Fe and P as elements relative to a mass content of Ni as an element [(Fe+P)/Ni] in the matrix is from 02 or more to 1.2 or less.

3. The friction material according to claim 1, wherein the content of Cu as an element is 10 mass % or less based on a total amount of the matrix.

4. The friction material according to claim 1, wherein the matrix further comprises, as elements, 0.5 mass % or more to 3 mass % or less of Si and 0.5 mass % or more to 15 mass % or less of Mn.

5. The friction material according to claim 1, wherein the solid particles comprise at least one kind selected from the group consisting of aluminum oxide, zirconia, silica, zircon sand, rutile sand, magnesium oxide and tungsten carbide.

6. The friction material according to claim 1, wherein the friction material comprises 1 mass % or more to 20 mass % or less of a friction modifier of at least one kind selected from the group consisting of talc, mica, calcium carbide and coke.

7. The friction material according to claim 2, wherein the content of Cu as an element is 10 mass % or less based on a total amount of the matrix.

8. The friction material according to claim 2, wherein the matrix further comprises, as elements, 0.5 mass % or more to 3 mass % or less of Si and 0.5 mass % or more to 15 mass % or less of Mn.

9. The friction material according to claim 3, wherein the matrix further comprises, as elements, 0.5 mass % or more to 3 mass % or less of Si and 0.5 mass % or more to 15 mass % or less of Mn.

10. The friction material according to claim 2, wherein the solid particles comprise at least one kind selected from the group consisting of aluminum oxide, zirconia, silica, zircon sand, rutile sand, magnesium oxide and tungsten carbide.

11. The friction material according to claim 3, wherein the solid particles comprise at least one kind selected from the group consisting of aluminum oxide, zirconia, silica, zircon sand, rutile sand, magnesium oxide and tungsten carbide.

12. The friction material according to claim 4, wherein the solid particles comprise at least one kind selected from the group consisting of aluminum oxide, zirconia, silica, zircon sand, rutile sand, magnesium oxide and tungsten carbide.

13. The friction material according to claim 2, wherein the friction material comprises 1 mass % or more to 20 mass % or less of a friction modifier of at least one kind selected from the group consisting of talc, mica, calcium carbide and coke.

14. The friction material according to claim 3, wherein the friction material comprises 1 mass % or more to 20 mass % or less of a friction modifier of at least one kind selected from the group consisting of talc, mica, calcium carbide and coke.

15. The friction material according to claim 4, wherein the friction material comprises 1 mass % or more to 20 mass % or less of a friction modifier of at least one kind selected from the group consisting of talc, mica, calcium carbide and coke.

16. The friction material according to claim 5, wherein the friction material comprises 1 mass % or more to 20 mass % or less of a friction modifier of at least one kind selected from the group consisting of talc, mica, calcium carbide and coke.

Description

EXAMPLES

(1) Although the present invention will be described in further detail below, with examples, the present invention is not limited to such examples. Commercially available raw material powders were prepared. The average particle size of each raw material powder is shown in Table 1. It should be noted that the average particle sizes of the raw material powders were measured by the Fisher method (Fisher Sub-Sieve Sizer (FSSS)) indicated in standard B330 of the American Society for Testing and Materials (ASTM).

(2) TABLE-US-00001 TABLE 1 Average Particle Raw Material Powder Size (m) Metal Fe 100 Powder Phosphorus-containing Iron 100 (99 mass % Fe, 1 mass % P) Phosphorus-containing Iron 100 (94 mass % Fe, 6 mass % P) Ni 5 Cu 40 Si 40 Mn 40 Hard Zircon Sand 150 Particle Aluminum Oxide 60 Powder Silica 200 Rutile Sand 150 Zirconia 150 Magnesium Oxide 150 Lubricant Graphite 300 Powder Molybdenum Disulfide 5 Tungsten Disulfide 5 Calcium Fluoride 150 Boron Nitride 5 Friction Coke 300 Modifier Talc 150 Powder Mica 150 Calcium Carbonate 40

(3) The prepared raw material powders were weighed so as to achieve each of the formulation compositions shown in Tables 2 and 3, and such weighed raw material powders were mixed by a mixer. The obtained mixture was molded into the shape of a brake pad. The obtained molded body and a back plate obtained by plating a surface of a steel sheet with copper were overlaid and pressure-sintered at the sintering temperature and sintering pressure as shown in Table 4. At this time, the resulting product was sintered in an Ar atmosphere for one hour.

(4) TABLE-US-00002 TABLE 2 Sample Number Invention Invention Invention Invention Invention Invention Invention Invention Invention Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Sample 8 Sample 9 Formu- Metal Phosphorus-containing 32.0 lation Powder Iron (1 mass %) Compo- Phosphorus-containing 20.5 24.3 28.1 18.9 30.8 19.1 23.4 23.2 sition Iron (6 mass %) (mass Ni 30.5 28.8 39.3 39.0 35.8 25.8 54.0 32.2 31.8 %) Cu 9.0 7.2 1.5 Si 1.7 1.8 2.0 1.7 1.7 1.7 2.8 1.5 Mn 4.5 4.6 4.5 0.5 4.5 4.5 2.0 5.3 Total of Metal Powder 66.2 67.2 70.1 69.3 68.1 62.8 75.1 58.4 63.3 Hard Zircon Sand 8.9 8.6 6.1 6.9 7.0 6.1 4.2 10.3 Particle Aluminum Oxide 5.4 2.5 3.1 3.8 10.4 5.9 8.8 Powder Silica 3.8 0.9 1.2 1.8 3.0 Rutile Sand 2.4 1.5 Zirconia 1.9 1.5 Magnesium Oxide 0.5 2.3 Total of Hard Particle 16.7 12.9 10.5 10.9 12.0 18.3 7.2 8.9 21.4 Lubri- Graphite 13.3 7.7 11.0 11.0 11.7 11.0 19.5 6.5 cant Molybdenum Disulfide 0.9 5.3 6.3 Powder Tungsten Disulfide 6.4 Calcium Fluoride 3.8 3.0 3.2 3.2 3.2 3.2 Boron Nitride 0.4 Total of Lubricant 17.1 11.1 14.2 15.1 14.9 14.2 11.7 25.8 6.5 Friction Coke 7.3 3.5 3.5 2.4 3.5 6.0 3.2 Modi- Talc 1.4 4.4 2.7 fier Mica 1.5 1.2 1.2 1.2 1.2 Powder Calcium Carbonate 0.5 2.5 2.9 Total of Friction 8.8 5.2 4.7 5.0 4.7 6.0 6.9 8.8 Total of Formulation 100 100 100 100 100 100 100 100 100 Composition

(5) TABLE-US-00003 TABLE 3 Sample Number Compar- Compar- Compar- Compar- Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative ative ative ative ative Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Sample 8 Sample 9 Formu Metal Fe 24.9 lation- Powder Phosphorus-containing 25.6 Compo- Iron (1 mass %) sition Phosphorus-containing 29.0 24.9 8.5 16.2 13.0 18.4 4.9 (mass Iron (6 mass %) %) Ni 22.0 30.1 36.6 55.9 25.5 23.0 30.5 8.0 30.1 Cu 13.7 24.2 45.1 Si 1.7 1.7 3.6 1.7 1.1 2.3 0.8 1.7 Mn 4.6 9.1 4.4 1.2 2.0 0.7 4.5 Total of Metal Powder 57.3 65.8 79.5 70.5 44.0 36.0 77.4 59.5 61.2 Hard Zircon Sand 9.1 8.8 5.9 21.4 10.5 6.0 10.5 10.0 Particle Aluminum Oxide 5.5 4.5 2.7 3.3 8.0 7.6 3.6 7.6 7.6 Powder Silica 3.0 2.0 1.8 5.2 Rutile Sand 4.0 Zirconia 2.9 Magnesium Oxide Total of Hard Particle 17.6 4.5 13.5 11.0 34.6 25.0 9.6 18.1 17.6 Lubri- Graphite 15.8 15.8 1.6 10.8 9.6 24.0 10.6 10.4 10.4 cant Molybdenum Disulfide 5.5 Powder Tungsten Disulfide 8.0 Calcium Fluoride 3.9 3.9 1.5 3.1 2.4 2.4 2.5 2.5 Boron Nitride Total of Lubricant 19.7 27.7 3.1 13.9 12.0 29.5 13.0 12.9 12.9 Friction Coke 3.4 1.0 2.7 3.5 6.1 3.5 3.3 3.3 Modi- Talc 1.0 fier- Mica 2.0 1.2 1.1 3.3 6.0 6.2 5.0 Powder Calcium Carbonate Total of Friction 5.4 2.0 4.9 4.6 9.4 9.5 9.5 8.3 Total of Formulation 100 100 100 100 100 100 100 100 100 Composition

(6) TABLE-US-00004 TABLE 4 Sintering Sintering Sample Number Temperature ( C.) Pressure (MPa) Invention Sample 1 750 3 Invention Sample 2 900 3 Invention Sample 3 950 3 Invention Sample 4 1000 3 Invention Sample 5 900 0.5 Invention Sample 6 900 1 Invention Sample 7 900 2 Invention Sample 8 900 4 Invention Sample 9 900 5 Comparative Sample 1 800 3 Comparative Sample 2 900 3 Comparative Sample 3 950 3 Comparative Sample 4 900 1 Comparative Sample 5 900 2 Comparative Sample 6 900 3 Comparative Sample 7 900 4 Comparative Sample 8 900 5 Comparative Sample 9 900 3

(7) As to the friction material obtained via sintering, the dimension was adjusted by means of polishing so as to obtain a sample being a brake-shaped friction material (friction member).

(8) The composition of the matrix of the obtained sample was measured using EDX. The results are shown in Tables 5 and 6.

(9) TABLE-US-00005 TABLE 5 Sample Number Invention Invention Invention Invention Invention Invention Invention Invention Invention Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Sample 8 Sample 9 Composition Fe 29.1 47.1 32.6 38.1 26.1 46.1 23.9 37.7 34.5 of Matrix P 1.9 0.5 2.1 2.4 1.7 2.9 1.5 2.4 2.2 (mass %) Ni 46.1 42.9 56.1 56.3 52.6 41.1 71.9 55.1 50.2 Cu 13.6 0.0 0.0 0.0 10.6 0.0 0.0 0.0 2.4 Si 2.6 2.7 2.9 2.5 2.5 2.7 0.0 4.8 2.4 Mn 6.8 6.8 6.4 0.7 6.6 7.2 2.7 0.0 8.4 Total 100 100 100 100 100 100 100 100 100 (Fe + P)/Ni 0.67 1.11 0.62 0.72 0.53 1.19 0.35 0.73 0.73

(10) TABLE-US-00006 TABLE 6 Sample Number Comparative Comparative Comparative Comparative Comparative Comparative Comparative Comparative Comparative Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Sample 8 Sample 9 Composition Fe 47.6 35.6 31.9 11.3 34.6 33.9 22.3 7.7 40.7 of Matrix P 3.0 2.3 0.3 0.7 2.2 2.2 1.4 0.5 0.0 (mass %) Ni 38.4 45.7 46.0 79.3 58.0 63.9 39.4 13.4 49.2 Cu 0.0 0.0 17.2 0.0 0.0 0.0 31.3 75.8 0.0 Si 3.0 2.6 4.5 2.4 2.5 0.0 3.0 1.3 2.8 Mn 8.0 13.8 0.0 6.2 2.7 0.0 2.6 1.2 7.4 Total 100 100 100 100 100 100 100 100 100 (Fe + P)/Ni 1.32 0.83 0.70 0.15 0.64 0.57 0.60 0.61 0.83

(11) Using the obtained samples (test pieces), the following friction test was conducted. The results are shown in Table 7.

(12) [Friction Test]

(13) Test apparatus: Inertia friction tester

(14) Moment of inertia: 12.25 kgm.sup.2

(15) Velocity: 42 m/s

(16) Contact pressure: 980 kPa

(17) Test piece shape: 25 mm25 mm10 mm

(18) Brake start temperature: 350 C.

(19) TABLE-US-00007 TABLE 7 Sample Number Friction Coefficient Invention Sample 1 0.60 Invention Sample 2 0.65 Invention Sample 3 0.68 Invention Sample 4 0.65 Invention Sample 5 0.58 Invention Sample 6 0.72 Invention Sample 7 0.71 Invention Sample 8 0.68 Invention Sample 9 0.64 Comparative Sample 1 0.54 Comparative Sample 2 0.45 Comparative Sample 3 0.43 Comparative Sample 4 0.51 Comparative Sample 5 0.42 Comparative Sample 6 0.47 Comparative Sample 7 0.41 Comparative Sample 8 0.40 Comparative Sample 9 0.42

(20) Table 7 indicates that the friction coefficient of any of the invention samples is 0.58 or more and, in turn, indicates that each invention sample has a higher friction coefficient than that of each comparative sample.

(21) Using the obtained samples, the following shearing test was conducted so as to measure the shearing strength between the friction material and the back plate in each sample. The results are shown in Table 8.

(22) [Shearing Test]

(23) Shearing strength was measured by a method conforming to the Japanese Industrial Standards Automotive partsDrum brake shoe assemblies and disc brake padShear test procedure (JISD4422). The shearing test was conducted at room temperature (23 C.) and a temperature of 300 C.

(24) TABLE-US-00008 TABLE 8 Shearing strength at Shearing strength Sample Number room temperature (MPa) at 300 C. (MPa) Invention Sample 1 15 13 Invention Sample 2 12 10 Invention Sample 3 9 7 Invention Sample 4 13 11 Invention Sample 5 14 12 Invention Sample 6 7 7 Invention Sample 7 10 8 Invention Sample 8 11 10 Invention Sample 9 8 8 Comparative Sample 1 7 5 Comparative Sample 2 6 4 Comparative Sample 3 6 4 Comparative Sample 4 5 3 Comparative Sample 5 3 3 Comparative Sample 6 4 4 Comparative Sample 7 5 2 Comparative Sample 8 5 2 Comparative Sample 9 6 4

(25) Table 8 indicates that the shearing strength of any of the invention samples is 7 MPa or more at either room temperature or 300 C. Table 8 further indicates that the shearing strength of each invention sample is generally higher than that of each comparative sample and, in turn, indicates that each invention sample involves excellent adhesion between the friction material and the back plate.

(26) Using the obtained samples, the following wear test was conducted.

(27) The results are shown in Table 9.

(28) [Wear Test]

(29) Test apparatus: Inertia friction tester

(30) Moment of inertia: 12.25 kgm.sup.2

(31) Velocity: 42 m/s

(32) Contact pressure: 2,000 kPa

(33) Test piece shape: 25 mm25 mm10 mm

(34) Brake start temperature: 100 C. or less

(35) TABLE-US-00009 TABLE 9 Amount of Sample Number wear (mm) Invention Sample 1 0.31 Invention Sample 2 0.21 Invention Sample 3 0.45 Invention Sample 4 0.38 Invention Sample 5 0.41 Invention Sample 6 0.33 Invention Sample 7 0.29 Invention Sample 8 0.32 Invention Sample 9 0.35 Comparative Sample 1 0.42 Comparative Sample 2 0.52 Comparative Sample 3 0.65 Comparative Sample 4 0.49 Comparative Sample 5 0.62 Comparative Sample 6 0.63 Comparative Sample 7 0.57 Comparative Sample 8 0.71 Comparative Sample 9 0.58

(36) Table 9 indicates that the amount of wear of any of the invention samples is 0.45 mm or less and, in turn, indicates that such amount of wear is generally smaller than that of each comparative sample, thereby leading to excellent wear resistance.

INDUSTRIAL APPLICABILITY

(37) The friction material of the present invention employs raw material powders which have a lower burden on the environment, and such friction material itself accordingly places a lower burden on the environment. The friction material of the present invention has excellent adhesion with a member to be joined, such as a back plate for holding a friction member which employs the friction material, and has a high friction coefficient. Further, the friction material of the present invention has a high friction coefficient even when the friction material is at a high temperature during the above-mentioned braking or intermittence. Therefore, the friction material of the present invention has high industrial applicability in the relevant technical field.