RU2801844C1 - Copper-nickel alloy for casting microwires in glass insulation - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to alloys for casting resistive microwires in glass insulation, and can be successfully implemented in the creation of circuitry for precision instrumentation. The alloy for casting microwires contains, wt%: nickel 40.0-42.0, silicon 2.5-3.2, boron 0.8-1.2, cerium 0.2-0.6, lanthanum 0.1 -0.5, yttrium 0.2-0.6, silicon carbide 4.0-6.0, copper - balance.

EFFECT: alloy has a tensile strength of at least 2500 MPa and is also characterized by high electrical properties.

1 cl, 1 tbl

Description

The invention relates to a micrometallurgical process for casting resistive microwires in glass insulation and can be successfully implemented in the creation of circuitry for precision instrumentation.

Known copper-nickel resistive alloys for casting microwires. These alloys .1974, AS No. 492580 dated 07.28.1975, AS No. 528342 dated 05.21.1976, AS No. 550447 dated 03.15.1977) have a high complex of electrophysical characteristics:

- low temperature coefficient of electrical resistance (less than 1⋅10 ^-5 K ^-1 ) in a wide temperature range;

- wide range of linear resistances (from 5 to 60 kOhm/m).

Of the above analogs in composition, the closest to the proposed invention is an alloy along.with. No. 528342 dated May 21, 1976, which contains rare earth elements (yttrium and lanthanum). The highest tensile strength of these alloys has an alloy according to a.s. No. 456023 dated September 13, 1974. For microwires from this alloy, the range of tensile strength values for diameters of 5-20 microns is 70-120 kg / mm ² (700-1200 MPa).

As a prototype, a copper-nickel alloy according to patent RU 2553799 was chosen, which is close to the proposed alloy in terms of achieving a technical effect - high strength, and having the following composition (wt.%):

nickel 33.0-56.0;

zirconium 3.0-5.0;

chromium 5.0-9.0;

hafnium 3.0-8.0;

cerium 0.2-2.0;

lanthanum 0.5-1.5;

yttrium 1.5-3.0;

boron nitride 0.6-1.2;

copper rest.

The disadvantage of all known alloys is that they have a low tensile strength, which causes significant difficulties in winding resistive elements.

Known alloys, including the prototype alloy, are designed to produce sheets, tapes, wires by plastic deformation methods. The proposed alloy contains silicon and boron as alloying components, which is necessary for casting microwires with borosilicate glass insulation. In this case, silicon and boron in the composition of the proposed alloy provide the necessary wetting of softened glasses with molten metal and the implementation of a stable process of casting microwires in glass insulation.

The technical result of the invention is the creation of an alloy on a copper-nickel basis, which makes it possible to obtain cast microwires in glass insulation, having a tensile strength of at least 2500 MPa, which will ensure the stable operation of modern winding equipment in the production of resistance circuit elements. This ensures high electrophysical properties of microwires.

The technical result of the invention is achieved by creating an alloy of the following composition (wt.%):

nickel 40.0-42.0;

silicon 2.5-3.2;

boron 0.8-1.2;

cerium 0.2-0.6;

lanthanum 0.1-0.5;

yttrium 0.2-0.6;

silicon carbide 4.0-6.0;

copper rest.

Copper-nickel base with a nickel content of 40.0-42.0 wt. % is chosen based on the fact that in this case the ratio of components in the double alloy of the microwire has the maximum value of the negative temperature coefficient of resistance (TCR, minus (12-14)⋅10 ^-5 K ^-1 ), and with additional alloying with other elements, this value increases, passing through zero.

Doping with silicon and boron during casting of microwires with insulation from borosilicate glasses (for example, type TU, S27-3, S37-2, S48-3, etc.) leads to a significant improvement in wetting in the "alloy-glass" system, which is necessary to ensure sustainable casting process. When the content in the silicon alloy is less than 2.5 wt. % and boron less than 0.8 wt. % of the desired effect is not. When the silicon content is more than 3.2 wt. % and boron more than 1.2 wt. % stability of the process is violated: it is possible to obtain only unbreakable segments of the microwire with a length of less than 30 meters.

The introduction of rare earth elements (cerium, lanthanum and yttrium) is due to the need to clean the alloy from gases - oxygen, hydrogen and nitrogen, respectively. These elements have the greatest affinity for these gases. When the content of these elements is less than 0.2 wt. %, 0.1 wt. % and 0.2 wt. %, respectively, no degassing effect is observed; at greater than 0.6 wt. %, 0.5 wt. % and 0.6 wt. %, there is a violation of the stability of the process of casting microwires - the process is very difficult to adjust and is unstable.

The microwires obtained from this alloy have a tensile strength of not more than 1000 MPa.

To improve the strength characteristics, an additional nanosized SiC powder with a fraction of 50-80 nm is added to the alloy in an amount of 4.0-6.0 wt. %. With a smaller amount of SiC in the alloy, only a slight increase in strength is observed (up to 1060–1200 MPa). With a larger quantity, the process of casting microwires is almost impossible to adjust.

The properties of cast microwires from the optimal composition of the alloy are shown in Table 1.

From this table it can be seen that microwires from an alloy of the optimal proposed composition have high mechanical and electrophysical characteristics, which make them suitable for use in the manufacture of resistive winding elements on modern equipment.

Experimental studies were carried out on the equipment of the Center for the Collective Use of Scientific Equipment "Composition, Structure and Properties of Structural and Functional Materials" of the National Research Center "Kurchatov Institute" - Central Research Institute of KM "Prometey" with the financial support of the Ministry of Science and Higher Education - agreement No. 13.TsKP.21.0014 (075 -11-2021-068). The unique identification number is RF-2296.61321X0014.

The essence of the invention is demonstrated in the following example.

Smelting of an alloy of the Cu-Ni-Si-B-Ce-La-Y-SiC system was carried out in an induction furnace of the SNOL type in alundum crucibles. The sequence of introduction of charge components is as follows: (Cu+Ni)→(Si+B)→SiC-(Ce+La+Y). The weight of the ingot was 1.0 kg. SiC was introduced into the melt using a special nozzle. The SiC powder was mixed in the electromagnetic field of the inductor and remained evenly distributed throughout the volume of the alloy after solidification. After the introduction of rare-earth elements, the melt was sucked into quartz tubes 5 mm in diameter using a KD-1 compressor. Thus, rods with a length of 35-45 mm were obtained, convenient for the formation of a “drop”.

The casting of the microwire was carried out on an ITMF-3 installation using glass tubes made of C37-2 borosilicate glass. Installation power 2 kW; operating frequency 880 kHz. The formation of the drop was carried out for 5 minutes. The process was set up quickly and proceeded very steadily.

Were obtained microwire with a core diameter of 5, 12 and 20 microns in length from 1.5 to 5.0 km (table 1).

Thus, the composition of the alloy for casting high-strength resistive microwires is optimized due to:

- the selected ratio between the amount of copper and nickel in the alloy to provide the required TCS of microwires;

- the introduction of silicon and boron, which ensures a quick setting of the casting process and its stable flow;

- the introduction of rare earth elements (cerium, lanthanum and yttrium), which leads to degassing of the "drop" and also guarantees a long and stable flow of the casting process;

- introduction of SiC, which provides a significant increase in the strength of the microwire, which guarantees its successful use when winding resistive elements on modern high-speed equipment.

Claims (2)

An alloy for casting microwires containing copper, nickel, cerium, lanthanum and yttrium, characterized in that it additionally contains boron, silicon and silicon carbide and has the following composition, wt.%: nickel 40.0-42.0 silicon 2.5-3.2 boron 0.8-1.2 cerium 0.2-0.6 lanthanum 0.1-0.5 yttrium 0.2-0.6 silicon carbide 4.0-6.0 copper rest