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Nitriding chromizing layer, preparing method of nitriding chromizing layer

A nitriding layer and chromizing technology, applied in coating, solid-state diffusion coating, metal material coating process, etc., can solve the problems of easy oxidation of workpiece, long time, high heating temperature, etc., to improve comprehensive performance and service life , improve adsorption and deposition, and good service performance

Active Publication Date: 2020-01-21
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although these processes are relatively simple, there are disadvantages such as high heating temperature, long time, large chromium consumption, and thin permeation layer, which limit their wide application.
As another example, the invention patent (patent number: 200810135237.5) of Wang Xiaorong etc. has prepared a kind of chromizing and nitriding layer by solid chromizing coating; but the nitriding temperature of this technology is high, the workpiece is easy to oxidize and deform; 2 N phase
Peng Xiao et al. used the method of low-temperature chromizing to modify the chromizing layer with rare earth oxides, but these methods also have defects such as slow penetration rate in the chromizing process.

Method used

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  • Nitriding chromizing layer, preparing method of nitriding chromizing layer
  • Nitriding chromizing layer, preparing method of nitriding chromizing layer

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preparation example Construction

[0027] An aspect of the embodiments of the present invention provides a method for preparing a chromium nitride layer, comprising:

[0028] Using glow ion nitriding technology, with high-purity NH 3 as a source of nitrogen to form a nitrided layer at least on the surface of the substrate; and,

[0029] Using vacuum chromizing technology, in a protective atmosphere, using chromizing agent to diffuse chromium at least on the surface of the substrate after nitriding treatment to form a chromium layer and obtain a nitrided chromium layer.

[0030] In some embodiments, the preparation method specifically includes:

[0031] The pretreated substrate is placed in a vacuum environment, activated by ion bombardment, heated at the same time, and NH is introduced when the temperature is raised to 380-400 °C 3 , and then continue to heat up to the glow nitriding temperature of 450-500°C, and control the glow voltage to 600-700V, so as to form a nitride layer at least on the surface of th...

Embodiment 1

[0084] The substrate is a stainless steel shaft sleeve, and the specific steps of the preparation method of the nitrided chromium layer are as follows:

[0085] 1) Nitriding pretreatment

[0086] Put the stainless steel bushing in petroleum ether, and clean it with ultrasonic stirring for 15 minutes. After removing the oil on the surface of the substrate, put it in acetone and ultrasonically clean it for 15 minutes, then ultrasonically clean it in absolute ethanol for 15 minutes, and finally take it out and dry it with nitrogen.

[0087] 2) The specific steps of glow ion nitriding are:

[0088] (1) Put the shaft sleeve treated in step 1) on the cathode disk of the furnace body, and heat while vacuuming, so that the temperature in the furnace body is raised to 400°C at a rate of 10°C / min.

[0089] (2) into NH 3 , its flow rate is controlled at 1.5L / min.

[0090] (3) Raise the temperature from 400°C to the glow temperature of 480°C at a rate of 10°C, keep it warm for 25 hours...

Embodiment 2

[0102] In the present embodiment, the specific steps of preparing the chromium nitride layer on the 316 stainless steel substrate are:

[0103] 1) Nitriding pretreatment

[0104] 1) step is identical with embodiment 1;

[0105] 2) The specific steps of glow ion nitriding are:

[0106] (1) is basically the same as step (1) in Example 1, the difference is: the temperature in the furnace body is warmed up to 390° C. at a rate of 15° C. / min;

[0107] (2) into NH 3 , its flow rate is controlled at 2.2L / min.

[0108] (3) Heat up from 390°C to glow temperature of 450°C at a rate of 15°C, hold for 26 hours, glow voltage is 650V, and pressure is 230Pa.

[0109] (4) Cool down from 450°C to 390°C at a rate of 5°C, cut off NH 3 Inflow, turn off the DC high-voltage power supply, let the substrate cool with the furnace, and get a nitrided layer after it comes out of the furnace.

[0110] 3) Vacuum chromizing, the process is divided into the following 4 steps:

[0111] (1) Embed the b...

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Abstract

The invention discloses a nitriding chromizing layer, a preparing method of the nitriding chromizing layer and application. The preparing method includes the steps that a glow ion nitriding technologyis adopted, highly-pure NH3 is adopted as a nitrogen source, and a nitriding layer is at least formed on the surface layer of a base material; and a vacuum chromizing technology is adopted, under theprotective atmosphere, a chromizing agent is used, diffusion chromizing is at least conducted on the surface layer of the base material obtained after nitriding treatment, and the nitriding chromizing layer is obtained. By means of the nitriding chromizing layer, the preparing method of the nitriding chromizing layer and the application, the problems that the traditional nitriding technology is high in temperature, the traditional chromizing technology is low in chromizing speed, Cr2N phase formation is difficult, and oxidization exists are solved, and high-performance nitriding chromizing surface treatment is achieved; in addition, the obtained nitriding chromizing layer has the beneficial effects that hardness is high, wear resistance is high, and the good service performance is achieved in a liquid sodium environment; and a good protection effect is achieved on parts operated under complex work conditions, the effect of preventing fasteners from being seized and the effect of selfwelding can be achieved, and therefore the comprehensive performance of parts is effectively improved, and the service life of the parts are effectively improved.

Description

technical field [0001] The invention relates to a chromium nitride layer, in particular to a chromium nitride layer on the surface of a substrate based on the combination of glow ion nitriding technology and vacuum chromizing technology, and its preparation method and application, which belong to the heat treatment process technology field. Background technique [0002] A large number of components such as bearings, racks, grippers, and fasteners are used in sodium-cooled fast reactor components, and they are used in harsh environments, such as mechanical friction pairs under conditions such as high-temperature sodium, vibration, impact, and dry friction. Problems such as self-welding, corrosion, and wear are particularly prominent, and the key components in it cannot be maintained frequently. In order to meet the above requirements, chromium nitriding technology must be used to ensure that the stainless steel has good service performance under the above working conditions. ...

Claims

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Application Information

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IPC IPC(8): C23C12/00
CPCC23C12/00
Inventor 张学东姜欣蒲吉斌王立平
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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