CN113308623A

CN113308623A - Novel non-evaporable low-temperature activated getter

Info

Publication number: CN113308623A
Application number: CN202010422097.0A
Authority: CN
Inventors: 熊玉华; 吴华亭
Original assignee: GRIMN Engineering Technology Research Institute Co Ltd
Current assignee: GRIMN Engineering Technology Research Institute Co Ltd
Priority date: 2020-05-18
Filing date: 2020-05-18
Publication date: 2021-08-27
Anticipated expiration: 2040-05-18
Also published as: CN113308623B

Abstract

The invention discloses a novel non-evaporable low-temperature activated getter, which consists of the following components in percentage by mass: 63-82% of titanium, 13-33% of cobalt and 2-5% of rare earth elements. The rare earth element is one or a mixture of lanthanum, cerium, praseodymium and neodymium. The non-evaporable low temperature activated getter of the present invention is used for absorbing active gases in vacuum or in noble gases, for increasing or maintaining vacuum in electric vacuum devices or for purifying noble gases. The non-evaporable low-temperature activated getter provided by the invention can be activated under the condition of heat preservation at 250-450 ℃ for 15-30 minutes, has good gettering performance, and is remarkably superior to St787 in gettering performance under the same activation condition. The getter is also safe from an environmental and safety point of view, and does not contain metals that are toxic or capable of forming toxic compounds. In addition, Ti is abundant in reserves and cheaper than Zr, and the low-temperature activated getter has economic advantages.

Description

Novel non-evaporable low-temperature activated getter

Technical Field

The invention relates to a novel non-evaporable low-temperature activated getter, belonging to the field of getters for electric vacuum devices.

Background

Non-evaporable getters have been widely used in various electrical vacuum devices and vacuum technology to achieve the goal of increasing or maintaining the vacuum of the device for a long period of time. Prior to use, the getter must be heated to a temperature and for a period of time under vacuum or inert gas conditions to remove the passivation layer from the surface and form a clean, highly reactive metal surface, a process known as activation. With the development of miniaturization and miniaturization of vacuum devices and the specialization of working environments, the performance requirements of vacuum devices on getters for maintaining vacuum are higher and higher, and the vacuum devices are required to have lower activation temperature and superior air suction performance.

The early low-temperature activated getter appeared in the 80 th of the 20 th century, the SAES company successfully develops the zirconium-vanadium-iron ternary alloy on the basis of the traditional getter, the zirconium-vanadium-iron ternary alloy is prepared by vacuum melting of 70%, 24.6% and 5.4% of zirconium, vanadium and iron by mass fraction respectively, the activation temperature range is 350-500 ℃, the temperature-activated ternary alloy has good room-temperature getter performance, the zirconium-vanadium-iron ternary alloy is still an excellent getter material with low price, convenience in use and strong adsorption capacity, and the SAES company names the zirconium-vanadium-iron ternary alloy as St 707. However, St 707 has the disadvantage of containing vanadium, compounds of which, in particular, its oxides, are toxic, and later SAES developed a non-evaporable Zr-Co-a getter (St 787), in which a is an element selected from yttrium, lanthanum, rare earths or mixtures thereof, which the SAES company has named St 787. St787 performs better than St 707 under the same activation conditions and the Zr-Co-a getter is safer from an environmental and safety point of view, since it does not contain metals that are toxic or can form toxic compounds.

Disclosure of Invention

Based on the above prior art, it is an object of the present invention to provide a novel non-evaporable low temperature activated getter having superior performance to St 787.

In order to achieve the purpose, the invention adopts the following technical scheme:

a novel non-evaporable low-temperature activated getter comprises the following components in percentage by mass: 63-82% of titanium, 13-33% of cobalt and 2-5% of rare earth elements.

The rare earth element is one or a mixture of lanthanum, cerium, praseodymium and neodymium.

Use of the novel non-evaporable low temperature activated getter for the sorption of active gases in vacuum or in an inert gas.

The active gas is one or more of hydrogen, oxygen, nitrogen, water vapor, carbon monoxide and carbon dioxide.

In this use, the getter is used for raising or maintaining a vacuum or for purifying inert gases in an electric vacuum device.

The preparation method of the non-evaporable low-temperature activated getter provided by the invention can select various known preparation methods in the prior art, can be prepared into a porous block, and can also be prepared into a film to be applied to a vacuum MEMS device.

The invention has the advantages that:

the non-evaporable low-temperature activated getter provided by the invention can be activated under the condition of heat preservation at 250-450 ℃ for 15-30 minutes, namely, the getter has better getter performance, and the getter performance is obviously superior to St787 under the same activation condition. The getter is also safe from an environmental and safety point of view, and does not contain metals that are toxic or capable of forming toxic compounds. In addition, Ti is abundant in reserves and cheaper than Zr, and the low-temperature activated getter has economic advantages.

Drawings

Figure 1 is the XRD pattern of the Ti70Co26Ce4 getter in example 2.

FIG. 2 is a comparison of hydrogen absorption performance of the non-evaporable, low temperature activated Ti-Co-RE getter versus the SAES St787 getter of examples 1-3.

FIG. 3 shows Ti in example 4₂Co and Zr₃Comparison of Co Hydrogen absorption Performance.

Detailed Description

The invention is further illustrated by the following specific examples, which are not intended to limit the scope of the invention.

In the following examples, the room temperature hydrogen absorption performance of the getter was measured by using a constant pressure method, which is a common method for measuring the absorption performance of the getter material. The measurement principle is based on the fact that when a molecular gas flow passes through a capillary (or orifice) of known conductance, a difference occurs in the gas pressure at the two ends of the capillary, generally by means of a constant getter material chamber pressure P_gMeasuring pressure P of the inlet chamber_mThe variation value of the time t is followed by calculating the air suction rate (S) and the air suction capacity (Q) of the material according to the formula.

Example 1

The method comprises the steps of smelting in an intermediate frequency vacuum smelting furnace to prepare a Ti70Co30 getter alloy ingot, wherein the mass percent of each element is Ti70 wt% and Co30 wt%, then crushing the ingot, screening out powder with the particle size of 20-40 microns, pressing 0.6g of powder into a wafer with the particle size of 10.5mm, activating the wafer at 350 ℃ for 30 minutes, and testing the room temperature hydrogen absorption performance by adopting a constant pressure method.

Example 2

The method comprises the steps of smelting in a medium-frequency vacuum smelting furnace to prepare a Ti70Co26Ce4 getter alloy ingot, wherein the mass percent of each element is Ti70 wt.%, Co26 wt.% and Ce4 wt.%, crushing the ingot, screening out powder with the particle size of 20-40 μm, pressing 0.6g of the powder into a wafer with the particle size of 10.5mm, activating at 350 ℃ for 30 minutes, and testing the hydrogen absorption performance at room temperature by using a constant pressure method. As shown in FIG. 1, the XRD pattern of the Ti70Co26Ce4 getter showed that the main phase of the getter is Ti with cubic structure₂A Co intermetallic compound phase and an alpha-Ti solid solution phase with a close-packed hexagonal structure.

Example 3

The method comprises the steps of preparing a Ti80.8Co14.2Ce5 getter alloy ingot by smelting in a medium-frequency vacuum smelting furnace, wherein the mass percentages of elements are Ti80.8 wt.%, Co14.2 wt.% and Ce5 wt.%, crushing the ingot, screening out 20-40 μm powder, pressing 0.6g of the powder into a wafer with the diameter of 10.5mm, activating at 350 ℃ for 30 minutes, and testing the room-temperature hydrogen absorption performance by adopting a constant pressure method.

As shown in FIG. 2, the hydrogen absorption performance of the non-evaporable, low temperature activated Ti-Co-RE getter compared to the SAES St787 getter in examples 1-3 is shown. The results in the figure show that under the same activation conditions, the hydrogen absorption performance of the Ti-Co-RE is obviously improved compared with that of Zr-Co-A (St 787). The getter phase in Zr-Co-A is Zr₃Co and alpha-Zr, and Zr₃Co is the main phase of Zr-Co-A which can be activated at low temperature; as shown in FIG. 1, the gettering phase in the Ti-Co-A of the present invention is Ti₂Co and alpha-Ti, Ti₂Co is the main phase which can be activated at low temperature by Ti-Co-A, and the research result shows that Ti₂The air suction performance of Co is obviously superior to that of Zr₃Co。

Example 4

Respectively smelting and preparing Ti by adopting a medium-frequency vacuum smelting furnace₂Co and Zr₃Ingot of Co, wherein Ti₂The mass percentages of the elements in the Co phase are Ti 61.9 wt.% and Co 38.1 wt.%, Zr₃The mass percentages of the elements in the Co phase were zr82.3wt.% and Co 17.7 wt.%. Respectively crushing ingots of the two components, screening out powder with the particle size of 20-40 mu m, pressing 0.6g of the powder into wafers with the particle diameter of 10.5mm, activating the wafers at 350 ℃ for 30 minutes, and testing the hydrogen absorption performance at room temperature by using a constant pressure method, wherein the result is shown in figure 3, and the Ti can be seen in the same activation condition₂The air suction performance of Co is obviously superior to that of Zr₃Co。

Example 5

Smelting by adopting a medium-frequency vacuum smelting furnace to prepare a TiCo ingot, wherein the mass percent of each element in the TiCo phase is 44.8 wt.% of Ti and 55.2 wt.% of Co, crushing the ingot, screening out 20-40 mu m powder, pressing 0.6g of powder into a wafer with the diameter of 10.5mm, activating at 350 ℃ for 30 minutes, testing the room-temperature hydrogen absorption performance of TiCo by adopting a constant pressure method, and testing the room-temperature hydrogen absorption performance of TiCo at the hydrogen pressure Pg of a selected getter chamber at 10^-4Almost no hydrogen absorption performance at Pa level. The above results also further indicate Ti₂Co rather than TiCo plays an important role in reducing the activation temperature of Ti-Co-RE and improving the hydrogen absorption performance.

Claims

1. The non-evaporable low-temperature activated getter is characterized by comprising the following components in percentage by mass: 63-82% of titanium, 13-33% of cobalt and 2-5% of rare earth elements.

2. Non-evaporable, low-temperature-activated getter according to claim 1, wherein said rare earth elements are mixtures of one or more of lanthanum, cerium, praseodymium, neodymium.

3. Use of a non-evaporable low temperature activated getter according to claim 1 for the sorption of active gases in vacuum or in inert gases.

4. Use according to claim 3, wherein the reactive gas is one or more of hydrogen, oxygen, nitrogen, water vapour, carbon monoxide and carbon dioxide.

5. Use according to claim 3, wherein the getter is used for increasing or maintaining a vacuum or for purifying inert gases in an electric vacuum device.