SU1606502A1 - Method of joining corundum ceramics to metal - Google Patents

Abstract

This invention relates to a process for making soldering of vacuum-tight titanium-ceramic partitioned units. The purpose of the invention is to improve the quality of large-sized nodes by increasing the electrical strength while maintaining the strength properties of the compounds and high yield of usable products. To do this, use a solder pad with a thickness of 20 - 40 microns in the form of a copper base with a uniform double-sided nickel coating at a mass ratio of NI and CU 1: (5-20), and when heated, the assembly is subjected to isothermal aging at 900-930 ° C, then heated at a rate of 5–15 ° C / min to 950–970 ° C and subsequent cooling is carried out at a rate of 5–10 ° C / min to 850–800 ° C. The tensile strength is 60-65 MPa, the yield is up to 90%, the breakdown voltage per one interelectrode gap is 10 kV. 1 tab.

Description

The invention relates to the technology for the manufacture of metal-ceramic products by the method of contact soldering in vacuum, more specifically to methods of connecting large-diameter corundum insulators with titanium using copper-nickel solder, and can be used in electrical and electronic equipment.

The aim of the invention is to improve the quality of large-sized assemblies by varying the electric strength while maintaining the strength properties of soldered joints and high yield of usable products. : The method is carried out as follows.

The ring-shaped ceramic samples to be soldered are subjected to mechanical cleaning, grinding, washing, and annealing in air for 0.5 h, and titanium rings are mechanically machined. Etching in 10% aqueous solution of hydrofluoric acid, washing with distilled water and drying. After this, a solder Ni-Cu-Ni layer of the required thickness and composition is placed between the parts being joined, loaded with a force of 0.5 ... 1 kg / cm and in a vacuum of 5 .10 ... 10 Pa smoothly, for example, with a speed of 7 ... 10 C / min heated to 900 ... and kept

 - 10 min (set time is -

35

about sd

about

ND

experimentally for each type and size of ceramics) for a more uniform heating of the assembly until the temperature field in it, degassing of the ceramics and relieving voltage in the metal. Then heating is continued at a speed of 3 ° C – min. to the soldering temperature of 95G. .970 ° C and the subsequent cooling is carried out to a speed of 5.o.10 ° C / min.

With crowded solder layers less than 20 microns, the vacuum density of the joints is disturbed, and with thicknesses greater than 40 microns, the size of the inclusions is higher than that of the prototype. Degrading Ni and Cu ratios result in deterioration of the joint properties: when the mass ratio of the components is 1:30, 25 ... 30 KPa and. Decreases the percentage of output of vacuum-tight samples, and at a ratio of 1: 4 increases the leakage, reducing the breakdown voltage by one interelectrode gap C 5 mm) in air to 4.5 ... 6 kV against T kV at the prototype.

The upper limit () of the temperature latch corresponds to the implementation of the assembly elements in solid state. At higher temperatures, the melting of the contact zone begins, which increases the duration of the interaction of liquid solder with ceramics and impairs the mechanical strength of the joints. At temperatures of exposure less EOO C in the Assembly during the subsequent heating to the soldering temperature, an unacceptable temperature gradient occurs,

In combination with the selected ratio of components, the heating rate of the assembly from 900, 930 to 950. ,, ... 9 70 С, is equal to 5 .., 15 C / min, practically eliminates the occurrence of sagging and optimizes the course of the subsequent soldering, and the selected The cooling mode promotes the formation of plastic phases in the solder, a decrease in stresses in the joint, and an improvement in its mechanical strength and vacuum density, despite the significant difference in the thermal absorption coefficients of structural titanium and ceramics.

According to the proposal, high-voltage three-, five-, and ten-section meta-ceramic insulators were made of UV-A6 ceramic rings; VC. 94

0

five

0

five

Q

35

40

45

polycor and other diameters from 114 to. 200 mm and titanium VT1-0 for accelerator tubes. Good quality and high yield are achieved.

Example 1. Preparation of a 10-section ceramic insulator

VK: 94-1.

Between the pretreated ceramic rings (diameter 160 mm, width 7 mm and height 15 mm) and titanium ring-shaped electrodes O, 4 ... O, 6 mm thick, a foil 20 microns thick from nickel-coated copper is placed at a Ni: Cu 1 ratio : 10; The resulting assembly is placed in a vacuum oven, loaded with a force of 1 kg / cm and heated at a rate of 10 ° C / min to 910 C at a pressure of Pa and maintained at this temperature for 10 minutes. Then the temperature is increased at a rate of 15 C / min to 970 ° C and the heating is stopped. Subsequent cooling is carried out at a rate of IO C / min up to,

Despite the significant difference in the CTE values (for titanium, 9.5 x X 10 degrees, for ceramics, 4.5 x X 10 degrees), the chosen mode promotes the formation of ductile solder, a decrease in stresses in the joint, an improvement in the mechanical strength and vacuum density. The percentage of usable nodes for a batch of 50 products by vacuum density was 88%, by electrical strength of 100% (10 kV for one interelectrode gap). Sample mechanical strength tests gave an average value of 64.8 points,

Example 2 and 3, The method is carried out analogously to example 1, but taking ceramic rings with a diameter of 200 mm, a width of 10 mm and a height of 15 mm and an interlayer, respectively, 30 and 40 microns thick. The percentage of usable knots for a batch of 10 products by vacuum density was 80%, by electrical strength 100%, the average tensile strength was 62.4 MPa,

Example 4, The method is carried out analogously to example 1, but the pinning is carried out for 10 minutes at, heating is carried out at a rate of 5 C / min to 950 C, and cooling is first at a rate of 5fC / min to and then at a rate of IO C / min to soot. The breakdown voltage of the assembly is

one

/ "95 kV, mechanical strength 60 - 65 Sha.

Example 5. The method is carried out analogously to example 4, only the NirCu ratio is 1: 5 and 22XC ceramics are used. The mechanical tensile strength of a 10-section insulator that dissipates the breakdown voltage of kV is N60 MPa.

Example 6. The method is carried out analogously to example 1, however, UV-46 ceramic rings are taken with an external diameter of 180 mm, a width of 12 mm and a height of 12 mm, and soldering is carried out in the parameters and modes - solder tire thickness 40 µm, mass the Ni: Cu ratio is 1:20, the isothermal loss is carried out at, the subsequent heating is at a rate of 10 ° C / min to 960 s, and cooling to 850 ° C at a rate of 10 ° C / min,

The resulting cermet unit is vacuously dense, has a breaking 55 ... 60 MPa, and the breakdown voltage per section is 10 kV.

Example 7. Soldering of a 5-section insulator made of VK 94-1 ceramic (22ХС) and titanium using the prototype method

Titanium ring-electrodes (VT1-0) with an outer diameter of 160 mm and thickness of 0.5 MMj galvanic coated with nickel and copper are expanded between the previously prepared ceramic rings (TBT diameter ftoi, width 7 mm and height 15 mm). The thickness of the nickel layer on each side of the titanium is 10 µm, of copper - also 10 µm. The resulting assembly is placed in a vacuum oven, heated to, maintained at this temperature for 5 minutes and cooled at a rate of 15 C / min.

V Testing of a series of obtained samples (5 products) showed that the description of the soldering technique according to the method to the prototype for the indicated cooling rate gives the yield of suitable nodes for vacuums (me 60% density, At the same time, on vacuum-tight insulators (3 samples) breakdown voltage in air

The method allows to obtain high-quality large-sized metal-ceramic compounds with high electrical strength (breakdown voltage of 15 mm interelectrode gap in air up to 10 kV) and high yield of useful products.

50

Claims (1)

Invention Formula The method of combining corundum ceramics with metal, including the placement between them of a multilayer copper-nickel strip, heating the assembly in is 6–7 kV per one interelectrode with vacuum, overhang and cooling, which is similar to the fact that, in order to improve the quality of large-sized units by increasing the electrical strength while simultaneously In some cases (one product), the solder spreads over the entire height of the insulator and bridges the inter- electrode gap. The average specific tensile strength for the entire series was 51.2 MPa. The cooling rate of the solder product affects its heat resistance. In the proposed method, the cooling rate is 5-10 sec / min. A further change in the cooling rate leads to an increase in the contact time of the solder liquid phase with ceramics and, consequently, to a decrease in electrical strength. products due to sagging. The cooling rate of more than 10 ° C / min impairs the temperature resistance of the product, and reduces the yield percentage for vacuum density. Cooling at the indicated speed is carried out to a temperature of 800-850 C, which is caused by the need for of titanium, (at 880 s, a basic transition occurs in structural titanium — r ftt). In addition, the solder interlayer relaxation, which impairs the strength and heat resistance of the joint, is most succinctly carried out at high temperatures. -800 ° C thirty 35 Several series of experiments were carried out with three-section metacloceramic nodes Ø 160 mm. The method was carried out as in Example 1, only the cooling rate and the shutdown temperature of the heaters were changed. The results obtained are tabulated. Each value in the table represents the average of about ten samples. 40 4S The method allows to obtain high-quality large-sized metal-ceramic compounds with high electrical strength (breakdown voltage of 15 mm interelectrode gap in air up to 10 kV) and high yield of useful products. 50 storing the strength properties of the compounds and the high yield of products, the gasket is made 0.02–0.04 mm thick in the form of a copper base with a uniform double-sided nickel coating at a mass ratio of NirCu "  1: (5-20), in the process of heating the assembly is first maintained at 900-930 0,; after that, with a speed of 5-15 degrees / min, the temperature is raised to 950-970 C, and then cooled with a speed of 5-10 degrees / min to 850-800 0. five eight ten ten 800 800 850 825 9.7 10.1 10.0 10.2 63.2 65.5 62.0 65.3