A nitriding method

A technology of nitriding and nitrogen atmosphere, applied in coating, metal material coating process, solid-state diffusion coating, etc., to achieve obvious nitriding effect, reduce co-infiltration temperature, easy composition and phase structure.

Active Publication Date: 2017-10-24
SHANDONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Due to the similar properties of rare earth elements, the structures and properties of R-T compounds formed between them and transition metals are also very similar, so nitrogen absorption under low-temperature and low-pressure nitrogen-containing atmosphere seems to be a common property of R-T compounds, but it is not Whether single-phase R-T compounds or non-stoichiometric R-T alloys have this property is unknown

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] The catalyst provided by the invention is used for gas nitriding of 316 stainless steel under pure nitrogen atmosphere.

[0042] Catalyst is RT x m y , select 12 kinds of alloys whose atomic ratio of R and T is about 1:13~1:2, the specific chemical composition is: (1) LaFe 11 Si 2 ; (2) CeFe 11 Ti; (3)PrFe 4 Al 8 ; (4) NdFe 9 Cr 2 ; (5) YFe 4 co 5 Si; (6)YFe 8 ; (7) SmFe 8 N 3 ; (8) NdFe 7 BH 3 ; (9) YFe 4 ;(10)SmFe 2 Ni 2 B; (11) YFe 3 ;(12)YFe 2 .

[0043] According to the above chemical formula, after mixing pure metal or intermediate alloy blocks with a purity higher than 99%, alloy ingots are obtained by argon-protected arc melting, and alloy powder slurry is obtained after ethanol-protected ball milling. The average particle size of the powder is 2.3~ 13.6 μm. The alloy containing H or N is treated in pure hydrogen or pure nitrogen atmosphere at 300-600°C for 1-5 hours.

[0044] Add an appropriate amount of polyethylene glycol and ethanol to ...

Embodiment 2

[0054] The catalyst provided by the invention is used for gas nitriding of 316 stainless steel under pure ammonia atmosphere.

[0055] Catalyst is RT x m y , select 12 alloys whose atomic ratio of R and T is about 1:13~1:2, and the specific chemical composition is close to the following ratio: (1) LaFe 11 Si 2 ; (2) CeFe 11 Ti; (3)PrFe 4 Al 8 ; (4) NdFe 9 Cr 2 ; (5) YFe 4 co 5 Si; (6)YFe 8 ; (7) SmFe 8 N 3 ; (8) NdFe 7 BH 3 ; (9) YFe 4 ;(10)SmFe 2 Ni 2 B; (11) YFe 3 ;(12)YFe 2 .

[0056] According to the above chemical formula, after mixing pure metal or intermediate alloy blocks with a purity higher than 99%, alloy ingots are obtained by argon-protected arc melting, and alloy powder slurry is obtained after ethanol-protected ball milling. The average particle size of the powder is 2.3~ 13.6 μm. The alloy containing H or N is treated in pure hydrogen or pure nitrogen atmosphere at 300-600°C for 1-5 hours.

[0057] Add an appropriate amount of polyethylene...

Embodiment 3

[0067] The catalyst provided by the invention is used for gas nitriding of 316 stainless steel at different temperatures under pure nitrogen atmosphere.

[0068] The selected catalyst is YFe 8 , prepare the alloy powder slurry according to the method described in Example 1, and apply it on the surface of 316 stainless steel.

[0069] Use a tube furnace for nitriding treatment, pre-evacuate to below 0.1Pa, fill with nitrogen with a purity of 99.995%, and the air pressure is 0.1-0.15MPa, hold at 300°C, 500°C, and 700°C for 10 hours, then cool with the furnace .

[0070] According to the method described in Example 1, the thickness of the nitriding layer, microhardness and corrosion weight loss rate of 316 stainless steel after nitrogen nitriding at different temperatures were measured, and the results are shown in Table 3. It can be seen that as the nitriding temperature increases, the thickness of the nitriding layer increases significantly, and the microhardness and corrosio...

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Abstract

The invention provides a nitriding method. Firstly, a catalyst is prepared and placed on the surface of a clean workpiece, and then treated at 300-700°C for 5-50 hours in a nitrogen-containing atmosphere, and finally the catalyst attached to the surface of the workpiece is Clean up and recycle. The method can significantly reduce the temperature of gas nitriding, especially when nitrogen gas is used for low-temperature nitriding, no ammonia-containing waste gas harmful to the environment and health will be produced.

Description

technical field [0001] The invention belongs to the field of chemical heat treatment, and relates to a gas nitriding method, specifically, it can nitriding or absorbing nitrogen in a nitrogen-containing atmosphere such as nitrogen gas or ammonia gas at a lower temperature, and is suitable for metal materials such as steel and titanium. Nitriding treatment. Background technique [0002] Nitriding is a chemical heat treatment technology that diffuses active nitrogen atoms [N] into the surface layer of steel, titanium and other metals, which can improve the metal surface hardness, wear resistance, fatigue strength and corrosion resistance. As an important surface strengthening technology, nitriding is widely used in machinery, petroleum, mining, national defense and other fields. Conventional nitriding methods include gas nitriding, ion nitriding, salt bath nitriding, catalytic nitriding, soft nitriding, etc. Among them, gas nitriding is widely used in industrial production be...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23C8/26
Inventor 谢鲲夏鹏成曹梅青岳丽杰孙金全
Owner SHANDONG UNIV OF SCI & TECH
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