Miniature electrical contact of high thermal stability

Abstract

The present invention relates to a male electrical contact of twist-pin type comprising an electrical terminal formed by a bundle comprising three central strands made of nickel or made of copper and 7 peripheral strands made of NiCrTiAl alloy and a bulge in the central portion, it being possible for said alloy to optionally additionally comprise Co and/or Mo. It also relates to the use of this contact in a micro-D connector, advantageously for applications at a service temperature 260 C.

Claims

1. A male electrical contact of twist-pin type, comprising: an electrical terminal formed by a bundle comprising three central strands made of copper and 7 peripheral strands made of NiCrTiAl alloy and a bulge in the central portion, the male electrical contact further including a cylinder and an electrical wire, an end of the electrical terminal being inserted into the cylinder, and the cylinder being provided with the electrical wire, wherein the NiCrTiAl alloy consists of, as a percentage by weight relative to a total weight of the alloy: chromium: 15%-25%; titanium: 1.5%-3.5%; cobalt: 0-25%; aluminum: 1%-2%; molybdenum: 0-11%; nickel: balance; and unavoidable impurities selected from the group consisting of Ag, B, Bi, C, Cu, Fe, Mn, P, Pb, S, Si, Zr and mixture thereof, wherein the three central strands made of copper are welded with the 7 peripheral strands made of NiCrTiAl alloy, wherein the three central strands are assembled with a pitch of between 1 and 5 mm left, and the 7 peripheral strands are assembled around with a pitch of between 1 and 5 mm right, wherein the bundle is coated with an electrolytic gold layer having a thickness of at least 2.6 m, and wherein the male electrical contact is configured to transmit electric current.

2. The male electrical contact as claimed in claim 1, wherein the peripheral strands are helically wound around the central strands.

3. The male electrical contact as claimed in claim 1, wherein the content of nickel+cobalt, as a percentage by weight relative to the total weight of the alloy, is between 62% and 83%.

4. The male electrical contact as claimed in claim 3, wherein the content of nickel+cobalt, as a percentage by weight relative to the total weight of the alloy, is between 64.5% and 81.5%.

5. The male electrical contact as claimed in claim 1, wherein the cobalt is between 10% and 22% by weight relative to the total weight of the alloy.

6. The male electrical contact as claimed in claim 1, wherein the molybdenum is between 3.5% and 11% by weight relative to the total weight of the alloy.

7. The male electrical contact as claimed in claim 6, wherein the molybdenum is between 4% and 10.5% by weight relative to the total weight of the alloy.

8. The male electrical contact as claimed in claim 1, wherein the three central strands have a diameter of between 0.069 and 0.109 mm.

9. The male electrical contact as claimed in claim 8, wherein the three central strands have a diameter of 0.089 mm.

10. The male electrical contact as claimed in claim 1, wherein the seven peripheral strands have a diameter of between 0.1 and 0.160 mm.

11. The male electrical contact as claimed in claim 10, wherein the seven peripheral strands have a diameter of 0.127 mm.

12. The male electrical contact as claimed in claim 1, wherein the bundle comprises no sublayer between the alloy and the electrolytic gold layer.

13. The male electrical contact as claimed in claim 1, wherein a service temperature of the male electrical contact is 260 C.

14. The male electrical contact as claimed in claim 1, wherein a magnetism value of the male electrical contact is less than 1 nT.

15. A micro-D connector containing the male electrical contact as claimed in claim 1.

16. The male electrical contact as claimed in claim 1, wherein the NiCrTiAl alloy consists of, as percentage by weight relative to the total weight of the alloy: chromium: 17%-22%; titanium: 1.7%-3.4%; cobalt: 2%-23%; aluminum: 1.5%; molybdenum 0-10.5%; nickel: 50%-80%; and the unavoidable impurities selected from the group consisting of Ag, B, Bi, C, Cu, Fe, Mn, P, Pb, S, Si, Zr and mixture thereof.

17. The male electrical contact as claimed in claim 1, wherein the three central strands are assembled with a pitch of 2 mm left, and the seven peripheral strands are assembled around with a pitch of 2.4 mm right.

18. The male electrical contact as claimed in claim 1, wherein a contact resistance of the male electrical contact is within a limit defined by the Mil-DTL-83513 standard.

Description

(1) The present invention will be better understood on reading the description of the figures and examples that follow, which are given by way of nonlimiting indication.

(2) FIG. 1 represents a perspective diagram of an example of a 15-point female micro-D connector according to the MIL-DTL-83513 standard.

(3) FIG. 2 represents a schematic side view of a male electrical contact of twist-pin type 1 comprising a bundle 2 provided with a bulge or bump 3 in the central portion, the bundle forming the electrical terminal. This electrical terminal is inserted into a cylinder 4 which is provided with an electrical wire 5.

(4) FIG. 3 represents a photo of a male electrical contact of twist-pin type without an electrical wire according to FIG. 2, of which the 3 central strands of the bundle are made of Cu and the 7 peripheral strands are made of CuBeCo alloy, before residence time in an oven (FIG. 3A) and after residence time in an oven at 260 C. under ambient atmosphere for 100 hours of mating with a female contact (FIG. 3B) (comparative example 1).

(5) FIG. 4 represents a photo of a male electrical contact of twist-pin type without an electrical wire according to FIG. 2, of which the 3 central strands of the bundle are made of Cu and the 7 peripheral strands are made of CuNiSnMn alloy, before residence time in an oven (FIG. 4A) and after residence time in an oven at 260 C. under ambient atmosphere for 100 hours of mating with a female contact (FIG. 4B) (comparative example 2).

(6) FIG. 5 represents the measurement in accordance with the MIL-DTL-83513 standard on 10 male electrical contacts of twist-pin type according to FIG. 2, of which the 3 central strands of the bundle are made of Cu and the 7 peripheral strands are made of CuNiSnMn alloy, of the separation force in N (Fmax, Fmin and Fmean) as a function of the residence time in an oven (h: hour) at 260 C. under ambient atmosphere, compared to the minimum force, as absolute value, required according to the MIL-DTL-83513 standard (standard max.) (comparative example 2).

(7) FIG. 6 represents a photo of a male electrical contact of twist-pin type without an electrical wire according to FIG. 2, of which the 3 central strands and the 7 peripheral strands of the bundle are made of AuCuPtAgZn alloy, before residence time in an oven (FIG. 6A) and after residence time in an oven at 260 C. under ambient atmosphere for 100 hours of mating with a female contact (FIG. 6B) (comparative example 3).

(8) FIG. 7 represents a photo of a male electrical contact of twist-pin type without an electrical wire according to FIG. 2, of which the 3 central strands of the bundle are made of Ni and the peripheral strands are made of NiCr20-Co18-TiAl alloy, before residence time in an oven (FIG. 7A) and after residence time in an oven at 260 C. under ambient atmosphere for 2000 hours of mating with a female contact (FIG. 7B) (example 1).

(9) FIG. 8 represents the measurement in accordance with the MIL-DTL-83513 standard on 10 male electrical contacts of twist-pin type according to FIG. 2, of which the 3 central strands of the bundle are made of Ni and the peripheral strands are made of NiCr20-Co18-TiAl alloy, of the separation force (Fmax, Fmin and Fmean) as a function of the residence time in an oven (h: hour) at 260 C. under ambient atmosphere, compared to the minimum force, as absolute value, required according to the MIL-DTL-83513 standard (max. standard) (example 1).

(10) FIG. 9 represents a photo of a male electrical contact of twist-pin type without an electrical wire according to FIG. 2, of which the 3 central strands of the bundle are made of Cu and the peripheral strands are made of NiCr20-Co18-TiAl alloy, before residence time in an oven (FIG. 9A) and after residence time in an oven at 260 C. under ambient atmosphere for 2000 hours of mating with a female contact (FIG. 9B) (example 5).

(11) FIG. 10 represents the measurement in accordance with the MIL-DTL-83513 standard on 10 male electrical contacts of twist-pin type according to FIG. 2, of which the 3 central strands of the bundle are made of Cu and the peripheral strands are made of NiCr20-Co18-TiAl alloy, of the separation force (Fmax, Fmin and Fmean) as a function of the residence time in an oven (h: hour) at 260 C. under ambient atmosphere, compared to the minimum force, as absolute value, required according to the MIL-DTL-83513 standard (max. standard) (example 5).

(12) FIG. 11 represents the wiring diagram for the measurement of the contact resistance according to the MIL-DTL-83513 standard (example 6).

(13) FIG. 12 represents the change in the values of low-intensity contact resistance in mOhm (measured at ambient temperature with the device from FIG. 11) with the time (in hours) that the male connector spent in the oven at 260 C., mated to a female connector, for a connector according to the invention (with Cu and NiCr20-Co18-TiAl bundle contact according to example 7) and a connector from the prior art (with Cu and CuBeCo bundle contacts according to comparative example 1) (example 9).

EXAMPLES

Comparative Example 1 (Cu and CuBeCo Bundle)

(14) TP contacts composed of 3 central strands (diameter=0.089 mm) made of copper and 7 peripheral strands (diameter=0.127 mm) made of copper, beryllium and cobalt alloy (CuBeCo: CuBe1.8-Co0.2), from the company NGK, (reference Berylco 25) are produced. The mechanical features of the alloy are listed in table 1 below:

(15) TABLE-US-00001 TABLE 1 Rm Rp0.2% E A Conductivity Composition (MPa) (MPa) (GPa) (%) (% IACS) Comparative CuBe1.8Co0.2 1260-1450 1090-1350 130 1 19-28 example 1

(16) The three central strands of the bundle are assembled with a 2 mm left pitch, then the seven strands around are assembled with a 2.4 mm right pitch. The tube is made of copper. The TP contacts are then inserted into female contacts having an internal diameter of 0.573 mm. The aging takes place at 260 C. under ambient atmosphere for 100 hours on 10 pairs of contacts. Visual observation shows that the bump of the contact is shrunk after aging (FIG. 3). After aging, the shrinkage of the bump is observed visually on these contacts and the insertion force in a 0.561 mm diameter gauge and the separation force of the contacts in a 0.584 mm diameter gauge according to the MIL-DTL-83513G standard are measured. The results are listed in table 2 below:

(17) TABLE-US-00002 TABLE 2 t in the oven (hours) 0 100 Comparative Mean engagement force (N) 1.14 0.27 example 1 Mean separation force (N) 0.49 0.07

(18) The engagement force is divided by 4 when the values before and after residence time in the oven are compared, the separation force is divided by 7. The MIL-DTL-83513G standard stipulates a maximum insertion force of 1.67 N and a minimum separation force of 0.14 N, as absolute value. The separation values obtained after 100 h at 260 C. are therefore below the limit of the standard.

(19) In conclusion, this contact cannot be used for applications at 260 C.

Comparative Example 2 (Cu and CuNiSnMn Bundle)

(20) TP contacts similar to those of comparative example 1 are produced, but using, for the 7 peripheral strands, a copper, nickel, tin and manganese alloy (CuNiSnMn: CuNi13-Sn7-Mn0.15) from the company Berda (reference Nibrodal 138), the features of which are found in table 3 below.

(21) TABLE-US-00003 TABLE 3 Rm Rp0.2% E A Conductivity Composition (MPa) (MPa) (GPa) (%) (% IACS) Comparative CuNi13Sn7Mn0.15 1309-1337 119 0.6-1 8.4 example 2

(22) The thermal aging is carried out at 260 C. under conditions similar to comparative example 1. After aging, the visual observation and the measurement of the insertion and separation forces are performed, as in comparative example 1. The results are listed in table 4 below.

(23) TABLE-US-00004 TABLE 4 t in the oven (hours) 0 113 264 500 1008 Comparative Mean engagement 0.76 0.55 0.48 0.66 0.48 example 2 force (N) Mean separation 0.36 0.23 0.16 0.22 0.21 force (N)

(24) The bumps of the contacts are flattened and a small bulge appears at the rear of the contact (FIG. 4). The mean forces obtained, presented in table 4, meet the standard, but the scattering thereof means that some of the contacts do not meet it (FIG. 5). Thus, a conclusion similar to comparative example 1 is reached, namely that this contact cannot be used for applications at 260 C.

Comparative Example 3 (AuCuPtAgZn Bundle)

(25) TP contacts similar to those of comparative examples 1 and 2 are produced, but using, for the 3 central strands and 7 peripheral strands, an AuCuPtAgZn alloy (Au71.5-Cu14.5-Pt8.5-Ag4.5-Zn1) from the company Texpart, the features of which are found in table 5 below.

(26) TABLE-US-00005 TABLE 5 Rm Rp0.2% E A Conductivity Composition (MPa) (MPa) (GPa) (%) (% IACS) Comparative Au71.5Cu14.5Pt8.5Ag4.5Zn1 1030-1380 900 110 2 12.2 example 3

(27) The thermal aging is carried out at 260 C. under the same conditions as for comparative examples 1 and 2. After aging, the visual observation and the measurement of the insertion and separation forces are performed, as in the 2 abovementioned comparative examples. The results are listed in table 6 below.

(28) TABLE-US-00006 TABLE 6 t in the oven (hours) 0 100 Comparative Mean engagement force (N) 1.47 0.49 example 3 Mean separation force (N) 0.59 0.12

(29) The bumps are also flattened (FIG. 6). The force results show that the separation forces are on average below the standard. Thus, the conclusion similar to the preceding 2 comparative examples is reached, namely that this contact cannot be used for applications at 260 C.

Example 1 (Ni and NiCr20-Co18-TiAl (UNS N07090) BundleMechanical Aspect)

(30) TP contacts of similar construction to the preceding comparative examples are produced, but using 3 central strands made of nickel and 7 peripheral strands made of NiCr20-Co18-TiAl alloy available from the company Alloy Wire International under the reference Nimonic 90, of which the features are found in table 7 below and the exact composition is found in table 8 below.

(31) TABLE-US-00007 TABLE 7 Rm Rp0.2% A Conductivity Composition (MPa) (MPa) E (GPa) (%) (% IACS) Example 1 NiCr20Co18TiAl 1500-1800 213-240 1.5

(32) TABLE-US-00008 TABLE 8 Composition (in %) DIN UNS Ni Co Cr Ti Al Example 1 NiCr20Co18TiAl N07090 54 15-21 18-21 2-3 1-2

(33) These TP contact-female contact pairs are subjected to thermal aging at 260 C. under ambient atmosphere for 2000 hours. In this example, 60 pairs were tested. After aging, as in the preceding comparative examples, the TP contact is taken back out of the female contact and the visual observation and the measurement of the insertion and separation forces are performed. The results are listed in table 9 below.

(34) TABLE-US-00009 TABLE 9 t in the oven (hours) 0 120 264 600 1008 1516 2016 Example 1 Mean 1.79 2.10 1.34 1.49 1.45 1.38 1.19 engage- ment force (N) Mean 1.07 0.89 0.70 0.67 0.85 0.57 0.55 separation force (N)

(35) Visually, the contacts retain their bump (FIG. 7). No difference is seen between the contacts before and after aging.

(36) The forces obtained, presented in table 9, show that even after 2000 h of aging, the mean separation force is greater, as absolute value, than that imposed by the standard. Furthermore, all the contacts meet this standard and not only the average. This is shown in FIG. 8. Consequently, it can be concluded that these TP contacts, unlike the preceding 3 comparative examples, can be used for applications at 260 C., since the separation forces of these contacts meet the MIL-DTL-83513 standard after residence time of 2000 h in the oven.

Example 2 (Ni and NiCr20-TiAl (UNS N07080) BundleMechanical Aspect)

(37) TP contacts of similar construction to the preceding example 1 are produced, but with 7 peripheral strands made of NiCr20-TiAl alloy available from the company Alloy Wire International under the reference Nimonic 80A, of which the features are found in table 10 below and the exact composition is found in table 11 below.

(38) TABLE-US-00010 TABLE 10 Rm Rp0.2% E A Conductivity Composition (MPa) (MPa) (GPa) (%) (% IACS) Example 2 NiCr20TiAl 1500-1800 222 1.3

(39) TABLE-US-00011 TABLE 11 Composition (in %) DIN UNS Ni Co Cr Ti Al Example 2 NiCr20TiAl N07080 72.5-79.2 <2 18-21 1.8-2.7 1-1.8

(40) The TP contact-female contact pairs are subjected to the same aging as above. In this example, 10 pairs were tested. After aging, as in example 1 and the preceding comparative examples, the TP contact is taken back out of the female contact and the visual observation and the measurement of the insertion and separation forces are performed.

(41) Visually, the contacts retain their bump as in the preceding example 1. Furthermore, the separation forces obtained are similar to the preceding example 1. They are listed in table 11a below:

(42) TABLE-US-00012 TABLE 11a before oven after 2005 h at 260 C. Example 2 Mean separation F (N) 0.66 0.59 Mean engagement 1.55 1.33 F (N)

(43) Consequently, this construction may also be used for applications at 260 C.

Example 3 (Ni and NiCr20-Co14-MoTiAl (UNS N07001) BundleMechanical Aspect)

(44) TP contacts of similar construction to the preceding examples 1 and 2 are produced, but with 7 peripheral strands made of NiCr20-Co14-MoTiAl alloy available from the company Alloy Wire International under the reference Waspaloy, of which the features are found in table 12 below and the exact composition is found in table 13 below.

(45) TABLE-US-00013 TABLE 12 Rm Rp0.2% E A Conductivity Composition (MPa) (MPa) (GPa) (%) (% IACS) Example 3 NiCr20Co14MoTiAl 1300-1500 211 1.4

(46) TABLE-US-00014 TABLE 13 Composition (in %) DIN UNS Ni Co Cr Ti Al Mo Fe Example 3 NiCr20Co14MoTiAl N07001 56.7-58.7 13.5 19 3 1.5 4.3 <2

(47) These TP contact-female contact pairs are subjected to thermal aging at 260 C. under ambient atmosphere for 2000 hours. In this example, 10 pairs were tested. After aging, as in the preceding examples 1 and 2, the TP contact is taken back out of the female contact and the visual observation and the measurement of the insertion and separation forces are performed.

(48) Visually, the contacts retain their bump as in the preceding examples 1 and 2. Furthermore, the separation forces obtained are also similar to the preceding examples 1 and 2. They are listed in table 13a below:

(49) TABLE-US-00015 TABLE 13a before oven after 2005 h at 260 C. Example 3 Mean separation F (N) 1.06 0.59 Mean engagement 1.75 1.44 F (N)

(50) Consequently, this construction may also be used for applications at 260 C.

Example 4 (Ni and NiCr19-Co11-MoTiAl (UNS N07041) BundleMechanical Aspect)

(51) TP contacts of similar construction to the preceding examples 1 to 3 are produced, but with 7 peripheral strands made of NiCr19-Co11-MoTiAl alloy available from the company Alloy Wire International under the reference Rene 41, of which the features are found in table 14 below and the exact composition is found in table 15 below.

(52) TABLE-US-00016 TABLE 14 Rm Rp0.2% E A Conductivity Composition (MPa) (MPa) (GPa) (%) (% IACS) Example 4 NiCr19Co11MoTiAl 1600-2000 218 1.3

(53) TABLE-US-00017 TABLE 15 Composition (in %) DIN UNS Ni Co Cr Ti Al Mo Example 4 NiCr19Co11MoTiAl N07041 52.6-56.6 12 18-20 3-3.3 1.4-1.6 9-10.5

(54) The TP contact-female contact pairs are subjected to the same aging as above. In this example, 10 pairs were tested. After aging, as in the preceding examples 1 to 3, the TP contact is taken back out of the female contact and the visual observation and the measurement of the insertion and separation forces are performed. Visually, the contacts retain their bump as in the preceding examples 1-3. Furthermore, the separation forces obtained are also similar to the preceding examples 1-3. They are listed in table 15a below:

(55) TABLE-US-00018 TABLE 15a before oven after 2005 h at 260 C. Example 4 Mean separation F (N) 1.08 0.50 Mean engagement 1.84 1.11 F (N)

(56) Consequently, this construction may also be used for applications at 260 C.

(57) Subsequently, the construction using the NiCr20-Co18-TiAl alloy from example 1 for the 7 peripheral strands was concentrated on, but similar results may be obtained with the 3 other alloys used for the 7 peripheral strands from examples 2-4.

Example 5 (Cu and NiCr20-Co18-TiAl BundleMechanical Aspect)

(58) TP contacts of similar construction to the preceding examples 1-4 are produced, but using 3 central strands made of copper and 7 peripheral strands made of NiCr20-Co18-TiAl alloy available from the company Alloy Wire International under the reference Nimonic 90, of which the features are found in table 7 above and the exact composition is found in table 8 above. TP contact-female contact pairs are subjected to thermal aging at 260 C. under ambient atmosphere for 2000 hours. After aging, as in the preceding examples 1-4, each TP contact is taken back out of the female contact and the visual observation and the measurement of the insertion and separation forces are performed. The results are listed in table 16 below.

(59) TABLE-US-00019 TABLE 16 t in the oven (hours) 0 120 288 600 1000 1624 2176 Example 5 Mean 1.07 1.03 0.88 0.88 0.99 1.02 0.99 engage- ment force (N) Mean 0.57 0.50 0.45 0.49 0.41 0.50 0.45 separation force (N)

(60) Visually, the contacts retain their bump (FIG. 9). No difference is seen between the contacts before and after aging. The forces obtained, presented in table 16, show that even after 2000 h of aging, the mean separation force is greater, as absolute value, than that imposed by the standard. Furthermore, all the contacts meet this standard and not only the average. This is represented visually in FIG. 10. Furthermore, the standard deviations obtained are very low for this example compared to the preceding ones. Consequently, this construction may also be used for applications at 260 C.

Example 6 (Ni and NiCr20-Co18-TiAl BundleContact Resistance)

Sub-Example 6a (Gold Coating Thickness=1.3 m)

(61) TP contacts of similar construction to example 1 are produced, on which a surface treatment is additionally applied. The surface treatment consists of an electrolytic gold coating having a thickness of around 1.3 m. Contact resistance measurements are carried out according to the wiring diagram presented in FIG. 11, as specified in the MIL-DTL-83513 standard. The values given between parentheses are in mm. A wire of AWG26 gauge was used for the wiring. The test is carried out at ambient temperature, for two set intensities. The latter and the conditions to be met according to the standard are presented in table 17 below.

(62) TABLE-US-00020 TABLE 17 Test conditions Condition to be met Contact resistance L = 2.5 A Vm < 65 mV Low intensity contact resistance L = 100 mA R < 28 mohm

(63) The results obtained are presented in table 18 below.

(64) TABLE-US-00021 TABLE 18 Low intensity contact Sample Contact resistance (mV) resistance (mOhm) 1 79.1 31.2 2 79.3 30.8 3 78.3 31.65 4 69 30.05 5 77.1 31.52 6 70.3 30.27 7 81.5 33.73 8 75.7 27.44 9 71.5 28.37 10 68.9 28.56 mean 75.1 30.36

(65) The mean values obtained for the two measurements are above the values set by the standard.

Sub-Example 6b (Gold Coating Thickness=2 m)

(66) TP contacts of identical construction to the preceding sub-example 6a are produced, but with an electrolytic gold coating having a thickness of around 2 m. The same tests were carried out as in the preceding sub-example 6a. The results are presented in table 19 below.

(67) TABLE-US-00022 TABLE 19 Low intensity contact Sample Contact resistance (mV) resistance (mOhm) 1 69.5 24.12 2 73.3 27.04 3 54.5 26.77 4 73.7 31.77 5 71.2 27.45 6 69.2 27.57 7 55.3 27.14 8 68.5 27.96 9 69.3 27.42 10 72.2 30.54 mean 67.7 27.78

(68) The values are still above the standard, but are closer thereto than the contacts of the preceding sub-example 6a. This shows that the contact resistance may move closer to the values of the standard by increasing the thickness of gold deposited.

Sub-Example 6c (Gold Coating Thickness=2.7 m)

(69) TP contacts of identical construction to the preceding sub-examples 6a and 6b are produced, but with an electrolytic gold coating having a thickness of around 2.7 m. The same tests were carried out as above. The results are presented in table 20 below.

(70) TABLE-US-00023 TABLE 20 Low intensity contact Sample Contact resistance (mV) resistance (mOhm) 1 51.4 24.93 2 51.5 25.50 3 53.7 25.71 4 54 25.97 5 54.4 26.40 6 56.1 26.67 7 56.4 27.06 8 56.7 27.23 9 57.3 27.60 10 58.7 27.78 mean 55.0 26.49

(71) The values obtained for the two types of measurement meet those defined by the standard. A gold thickness of 2.7 m on the Ni and NiCr20-Co18-TiAl contacts therefore makes it possible to comply with the standard when it comes to the contact resistances.

Example 7 (Cu and NiCr20-Co18-TiAl BundleContact Resistance)

(72) A TP contact of similar construction to examples 5 is produced. An electrolytic gold coating having a thickness of around 2.6 m is also produced. The same tests were carried out as in the preceding sub-examples 6a-6c. The results are presented in table 21 below.

(73) TABLE-US-00024 TABLE 21 Low intensity contact Sample Contact resistance (mV) resistance (mOhm) 1 47.9 28.89 2 48.7 27.52 3 50.5 25.76 4 57.5 23.96 5 52.9 27.12 6 53.6 26.85 7 50.6 29.02 8 48.0 28.27 9 50.0 30.37 10 48.0 26.87 mean 50.8 27.46

(74) This solution shows that replacing the three nickel strands with more conductive copper strands makes it possible to significantly lower the contact resistance until the value of standard copper-beryllium contacts (52 mV) is achieved. As regards the low intensity contact resistance, the latter is affected very little by the change of material. But values close to the standard are obtained.

Example 8 (Cu and NiCr20-Co18-TiAl BundleAmagnetic Aspect)

(75) On the contacts produced in example 5, measurements of residual magnetism were carried out according to the procedure defined in the GFSC-S-311 standard, using a three-dimensional magnetometer. Firstly, the initial magnetic field is measured. Next, the contacts are magnetized with a 500 mT field using a magnet. A new measurement of residual magnetic field is carried out. Lastly, a demagnetization phase is carried out by applying an alternating magnetic field having a value of greater than 500 mT. A measurement is again carried out. The three measurements revealed a residual magnetism of less than 1 nT, a critical value below which the contacts tested are considered to be amagnetic.

Example 9 (Comparison Between a Contact According to the Invention (Cu and NiCr20-Co18-TiAl Bundle According to Example 7) and a Contact from the Prior Art (Cu and Cu-be-Co Bundle According to Comparative Example 1))

(76) The change in the low intensity contact resistance values (in mOhm) with time (in hours) that the male connector spent in the oven at 260 C., mated to a female connector, was measured according to the wiring diagram presented in FIG. 11, as specified in the MIL-DTL-83513 standard at ambient temperature for the two types of contact. The connectors were unmated-remated 5 times before the contact resistance measurement.

(77) A wire of AWG26 gauge was used for the wiring. The conditions of the test and the conditions to be met according to the standard are presented in table 17 of example 6.

(78) The results are given in FIG. 12.

(79) It is obvious that the connector produced with standard contacts of the prior art no longer ensures a good electrical contact, not least after about a hundred hours mated at 260 C.