Connecting component material

Abstract

A connecting component material used as a material constituting a connecting component, wherein the connecting component material is obtained by using a Ni-plated metal plate in which a Ni plating layer is formed on the surface of a metal plate, and the average depth (R) of a surface roughness motif in at least one direction on the surface of the Ni plating layer is 1.0 m or above, and by forming a Sn plating layer having a thickness of 0.3 to 5 m on the Ni plating layer of the Ni-plated metal plate; the connection component material makes it possible to reduce friction and minimize abrasion of the material when a connecting component such as an electrical connection terminal is fitted, and to improve the reliability of a stable electrical connection; and the connecting component material can be used in e.g., electrical contact components such as lead frames, harness plugs, and connectors used in electrical and electronic devices and the like.

Claims

1. A material for a connecting member used as a raw material of a connecting member, comprising a Ni-plated metal plate in which a Ni plating layer is formed on a surface of a metal plate, and a mean depth R of a roughness motif is 1.0 m or more in at least one direction on the surface of the Ni plating layer, and a Sn plating layer having a thickness of 0.3 to 5 m formed on the Ni plating layer of the Ni-plated metal plate.

2. The material for a connecting member according to claim 1, wherein a mean width RSm of a valley depth and a peak height existing on the surface of the Ni plating layer is more than 0 m and 200 m or less in the same direction as the direction of the mean depth R of the roughness motif of the surface of the Ni plating layer.

3. The material for a connecting member according to claim 1, wherein the metal plate is a stainless steel plate.

4. The material for a connecting member according to claim 1, wherein the metal plate is a copper plate or a copper alloy plate.

Description

EXAMPLES

(1) Next, the present invention is more specifically described based on working examples. However, the present invention is not limited only to the examples.

Examples 1 to 9 and Comparative Examples 1 to 5

(2) As a base material, a stainless steel plate (SUS430) was used. A roughening treatment was appropriately carried out on the surface of the stainless steel plate by using a work roll or a polishing belt each having a roughened surface, to give a stainless steel plate having a various surface roughness and a thickness of 0.2 mm.

(3) A roughness motif mean depth R and a mean width RSm of a valley depth and a peak height of the stainless steel plate obtained in the above were determined by the following methods. The results are shown in the column of Motif depth R and Mean width RSm in Table 1, respectively.

(4) [Methods for Determining Roughness Motif Mean Depth R and Mean Width RSm of a Valley Depth and a Peak Height]

(5) A test piece having a length of 50 mm and a width of 50 mm was cut out from the stainless steel plate. The test piece was washed with acetone by using ultrasonic waves. Thereafter, a roughness motif mean depth R of the test piece was determined in accordance with ISO 12085 by using a contact roughness meter manufactured by Tokyo Seimitsu Co., Ltd. under the tradename of SURFCOM 1400B, and a mean width RSm of a valley depth and a peak height was determined in accordance with JIS B0601-1994.

(6) Incidentally, when the roughness motif was determined, the upper limit length of the roughness motif was set to 0.5 mm. The roughness motif mean depth R and the mean width RSm of a valley depth and a peak height were determined three times, respectively, in a direction vertical to the direction of rolling of the test piece, and each average of the values was calculated.

(7) Next, each of the test pieces was subjected to alkali degreasing and an acid washing treatment by a conventional method. Thereafter, Ni strike plating and Ni plating of each test piece were carried out based on the following conditions, to form a Ni plating layer on the test piece. The roughness motif mean depth R and mean width RSm of a valley depth and a peak height of the test piece on which the Ni plating layer was formed were determined in the same manner as described above. The results are shown in Table 1. Thereafter, Sn plating of the test piece was carried out under the following conditions to form a Sn plating layer on the Ni plating layer of the test piece, to give a test piece on which a Ni plating layer having a thicknesses shown in Table 1 was formed.

(8) [Conditions for Ni Strike Plating]

(9) Ni plating solution (Wood's bath): 240 g/L of nickel chloride and 125 mL/L of hydrochloric acid (pH: 1.2)

(10) Temperature of plating solution: 35 C.

(11) Current density: 8 A/dm.sup.2

(12) [Conditions for Ni Plating]

(13) Ni plating solution (Watts bath): 300 g/L of nickel sulfate, 45 g/L of nickel chloride and 35 g/L of boric acid (pH: 3.9)

(14) Temperature of Plating solution: 50 C.

(15) Current density: 8 A/dm.sup.2

(16) [Conditions for Sn Plating]

(17) Sn plating solution: 50 g/L of Sn.sup.2+ and 120 mL/L of a free acid, commercially available from Uemura & Co., Ltd. under the trade name of TYNADES GHS-51 (pH: 0.2)

(18) Anode: Sn plate

(19) Temperature of solution: 35 C.

(20) Current density: 10 A/dm.sup.2

(21) In addition, the thickness of the Ni plating layer and the thickness of the Sn plating layer were measured in accordance with the following method. The results are shown in Table 1.

(22) [Method for Measuring Thickness of Ni Plating Layer and Thickness of Sn Plating Layer]

(23) The thickness of the Ni plating layer and the thickness of the Sn plating layer were measured in accordance with the Electrolytic Test Method prescribed in JIS H8501 by using an electroplating thickness measuring instrument manufactured by Chuo Seisakusho, Ltd.

(24) Next, as properties of the test piece on which the Sn plating layer was formed, which was obtained in the above, maximum contact resistance and coefficient of friction of the test piece during carrying out a fine sliding friction test were examined in accordance with the following methods. The results are shown in Table 1.

(25) [Maximum Contact Resistance During Carrying out a fine Sliding Friction Test]

(26) Simulating electric contact portions in a fitting-type coupling member, change of contact resistance between materials at the fine sliding portion was evaluated by using a sliding tester manufactured by Kabushikikaisha Yamasaki Seiki Kenkyusho.

(27) First, a platy test piece (male test piece) was cut out from the test piece on which the Sn plating layer was formed, and the male test piece was fixed on a horizontal table. A semispherical test piece (female test piece having a diameter of 1.5 mm) was cut out from the same test piece on which the Sn plating layer was formed as mentioned above, and the female test piece was put on the male test piece, to contact the male test piece with the female test piece. Thereafter, a load of 2.0 N was applied to the female test piece by an elastic spring, to push the male test piece. A constant current was applied between the male test piece and the female test piece. The male test piece was slid in a horizontal direction (sliding distance: 50 m, sliding frequency: 1.0 Hz) by using a stepping motor, and the maximum contact resistance was determined by a four-terminal method until the number of times of the sliding reached 2000 under the conditions of an open circuit voltage of 20 mV and a current of 10 mA. An acceptance criterion was set such that the maximum contact resistance was 100 m or less until the number of times of the sliding reached 2000.

(28) [Coefficient of Friction]

(29) A test piece having a length of 40 mm and a width of 40 mm was cut out from the test piece on which the Sn plating layer was formed. Using a stainless steel ball having a diameter of 10 mm, coefficient of dynamic friction of the test piece was determined by means of a frictional wear tester manufactured by Rhesca Co., Ltd. under the conditions of a load of 4 N, a radius of 7.5 mm and a rotational speed of 12.7 rpm after the ball was rotated 50 times. An acceptance criterion was set such that the coefficient of dynamic friction was 0.3 or less.

Example 10

(30) A test piece on which the formed Sn plating layer was formed was produced in the same manner as in Example 1, except that conditions for Ni plating employed in Example 1 were changed to the following conditions.

(31) [Conditions for Ni Plating]

(32) Ni plating solution (Watts bath+brightener): 300 g/L of nickel sulfate, 45 g/L of nickel chloride, 35 g/L of boric acid (pH: 3.9), 2 g/L of saccharin sodium and 0.2 g/L of 2-butyne-1,4-diol

(33) Temperature of plating solution: 50 C.

(34) Current density: 8 A/dm.sup.2

(35) Next, as properties of the test piece on which the Sn plating layer was formed, which was obtained in the above, maximum contact resistance and coefficient of friction of the test piece during carrying out a fine sliding friction test were examined in the same manner as described above. The results are shown in Table 1.

Example 11

(36) A test piece on which the formed Sn plating layer was formed was produced in the same manner as in Example 1, except that a copper alloy plate having a thickness of 0.2 mm manufactured by Kobe Steel, Ltd. under a product number of CAC60 was used in place of the stainless steel plate used in Example 1.

(37) Next, as properties of the test piece on which the Sn plating layer was formed, which was obtained in the above, maximum contact resistance and coefficient of friction of the test piece during carrying out a fine sliding friction test were examined in the same manner as described above. The results are shown in Table 1.

Comparative Example 6

(38) A test piece on which the formed Sn plating layer was formed was produced in the same manner as in Example 1, except that conditions for Ni plating employed in Example 1 were changed to the following conditions.

(39) [Conditions for Ni Plating]

(40) Ni plating solution (Watts bath): 300 g/L of nickel sulfate, 45 g/L of nickel chloride and 35 g/L of boric acid (pH: 3.9)

(41) Temperature of plating solution: 50 C.

(42) Current density: 2 A/dm.sup.2

(43) Next, as properties of the test piece on which the Sn plating layer was formed, which was obtained in the above, maximum contact resistance and coefficient of friction of the test piece during carrying out a fine sliding friction test were examined in the same manner as described above. The results are shown in Table 1.

Comparative Example 7

(44) A test piece on which the formed Sn plating layer was formed was produced in the same manner as in Example 1, except that conditions for Ni plating employed in Example 1 were changed to the following conditions.

(45) [Conditions for Ni Plating]

(46) Ni plating solution (chloride bath): 300 g/L of nickel chloride and 35 g/L of boric acid (pH: 3.9)

(47) Temperature of plating solution: 50 C.

(48) Current density: 2 A/dm.sup.2

(49) Next, as properties of the test piece on which the Sn plating layer was formed, which was obtained in the above, maximum contact resistance and coefficient of friction of the test piece during carrying out a fine sliding friction test were examined in the same manner as described above. The results are shown in Table 1.

Comparative Example 8

(50) A copper alloy plate having a thickness of 0.2 mm was used in place of the stainless steel plate, and a mold on which fine concavo-convex shapes were formed at a constant pitch was pushed on the surface of the copper alloy plate in accordance with a method described in Japanese Patent Unexamined Publication No. 2011-204617 so as to carry out a roughening treatment, to give a copper alloy plate having concavo-convex shapes. The roughness motif mean depth R and mean width RSm of the concavo-convex shapes of the obtained copper alloy plate having the concavo-convex shapes were determined in the same manner as described above. The results are shown in Table 1.

(51) Next, Cu plating of the copper alloy plate having concavo-convex shapes obtained in the above was carried out under the following Cu plating conditions. Thereafter, Sn plating of the above Cu-plated plate was carried out in the same manner in Example 1, to give a test piece on which a Sn plating layer was formed. Thereafter, the test piece on which the Sn plating layer was formed, which was obtained in the above was subjected to a reflow treatment at a temperature of 280 C. for 10 seconds.

(52) [Conditions for Cu Plating]

(53) Cu plating solution (copper sulfate plating bath): 200 g/L of copper sulfate and 45 g/L of sulfuric acid

(54) Temperature of plating solution: 30 C.

(55) Current density: 15 A/dm.sup.2

(56) Thickness of Cu plating layer: 0.15 m

(57) This copper alloy plate is not a plate having a surface on which a Ni plating layer is formed, but a plate having a surface on which a Cu plating layer is formed. Accordingly, the column of the Ni-plating layer described in Table 1 shows a thickness of the Cu plating layer, a motif depth R on the surface of the metal plate on which the Cu plating layer is formed, and the mean width RSm on the surface of the Cu plating layer.

(58) Next, as properties of the test piece on which the Sn plating layer was formed, which was obtained in the above, maximum contact resistance and coefficient of friction of the test piece during carrying out a fine sliding friction test were examined in the same manner as described above. The results are shown in Table 1.

(59) TABLE-US-00001 TABLE 1 Metal plate Ni plating layer Thickness of Sn plating Maximum Ex. and Motif Mean Thickness of Ni Motif Mean layer (m) of Ni-plated contact Comp. depth width plating layer depth width metal plate on which Sn resistance Coefficient Ex. No. R (m) RSm (m) (m) R (m) RSm (m) plating layer is formed (m) of friction Ex. 1 1.10 62 0.3 1.06 32 0.3 12 0.16 Ex. 2 3.73 129 0.3 3.59 130 1.0 26 0.21 Ex. 3 1.20 79 0.5 1.15 82 0.4 11 0.19 Ex. 4 3.84 160 0.7 3.70 165 2.0 37 0.23 Ex. 5 1.11 0.01 1.0 1.08 0.02 5.0 48 0.29 Ex. 6 1.38 42 3.0 1.23 44 3.0 13 0.28 Ex. 7 4.23 200 0.3 4.11 203 0.3 49 0.17 Ex. 8 5.62 243 0.4 5.55 245 5.0 38 0.30 Ex. 9 2.61 221 0.7 2.59 224 1.0 45 0.20 Ex. 10 6.98 121 3.0 3.42 172 2.0 29 0.27 Ex. 11 3.84 160 0.2 3.36 63 0.3 90 0.31 Comp. Ex. 1 0.97 59 0.3 0.93 23 0.3 1600 0.43 Comp. Ex. 2 0.75 70 0.3 0.72 72 1.0 1000 0.55 Comp. Ex. 3 1.00 165 0.5 0.98 80 3.0 580 0.47 Comp, Ex. 4 3.84 160 0.7 3.70 150 0.2 1430 0.23 Comp. Ex. 5 1.21 38 1.0 1.10 40 5.3 230 0.67 Comp. Ex. 6 1.20 79 3.0 0.98 88 1.0 210 0.51 Comp. Ex. 7 1.20 79 1.0 0.74 98 2.0 320 0.55 Comp. Ex. 8 1.27 80 0.15 1.25 81 1.0 190 0.35

(60) From the results shown in Table 1, it can be seen that the test piece obtained in each example is small in coefficient of friction and suppressed in increase of maximum contact resistance even when fine sliding of a connecting member is repeated. Since a plate of a copper alloy which is softer than stainless steel is used as a base material in the test piece obtained in Example 11, it can be seen that the test piece is slightly higher in coefficient of friction and maximum contact resistance than the test pieces obtained in Examples 1 to 10.

(61) On the contrary, the test piece obtained in each comparative example was large in coefficient of friction and increased in maximum contact resistance when fine sliding of a connecting member is repeated. In addition, since each test piece obtained in Comparative Examples 1 to 3, 6 and 7 had a small roughness motif mean depth R after the formation of a Ni plating layer, and Sn did not remain in the concave portion of the Ni plating layer, the Ni plating layer was abraded, and moreover a metal plate which was used as a base material was abraded. As a result, maximum contact resistance was increased. Since the test piece obtained in Comparative Example 4 did not have a Sn plating layer having a thickness sufficient for remaining Sn in the concave portion of the Ni plating layer, maximum contact resistance was increased. In addition, as to the test piece obtained in Comparative Example 5, although a Sn plating layer remained in the concave portion of a Ni plating layer, since the Sn plating layer was thick, an oxide of Sn was formed by fine sliding, and thereby maximum contact resistance was increased.

(62) In addition, since a soft copper alloy plate was used as a base material in the test piece obtained by a conventional manner in Comparative Example 8, a CuSn alloy layer which was a thin, hard and brittle film was easily abraded, and coefficient of friction of the test piece was increased after the CuSn alloy layer was abraded. After the abrasion of the CuSn alloy layer, maximum contact resistance was increased since the copper alloy plate was abraded when the number of times of sliding was increased.

INDUSTRIAL APPLICABILITY

(63) The material for a connecting member of the present invention is expected to be used in, for example, electrical contact members such as a connector, a lead frame and a harness plug, which are used in an electrical instrument, an electronic instrument and the like.