Nitriding catalyst

A catalyst and nitriding technology, applied in the field of chemical heat treatment, to achieve the effect of reducing the amount of rare earth used, shortening the heat treatment time, and reducing the heat treatment temperature

Inactive Publication Date: 2014-01-22
SHANDONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, whether non-single-phase R-T compounds or non-stoichiometric R-T alloys have low-temperature nitrogen absorption characteristics and catalytic effects is still unknown.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] The catalyst provided by the invention is used for gas nitriding of 316 stainless steel under pure nitrogen atmosphere.

[0041] 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 .

[0042] 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.

[0043] Add an appropriate amount of polyethylene glycol and ethanol to ...

Embodiment 2

[0053] The catalyst provided by the invention is used for gas nitriding of 316 stainless steel under pure ammonia atmosphere.

[0054] 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 .

[0055] 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.

[0056] Add an appropriate amount of polyethylene...

Embodiment 3

[0066]The catalyst provided by the invention is used for gas nitriding of 316 stainless steel at different temperatures under pure nitrogen atmosphere.

[0067] The catalyst is YFe8, the alloy powder slurry is prepared according to the method described in Example 1, and coated on the surface of 316 stainless steel.

[0068] 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 .

[0069] 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 corrosion resistanc...

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Abstract

The invention provides a nitriding catalyst which is an alloy with a general formula of RTxMy, wherein R is one of rare earth metals: La, Ce, Pr, Nd, Y, Sm and the like or combination thereof, T is one of metals: Fe, Co, Ni, Mn, Ti, V, Cr, Si, Al, Mg, Sn, Zn and the like or combination thereof, M is one of interstitial elements: H, B, C, N, P and the like or combination thereof, x is ranged from 1 to 20 and y is ranged from 1 to 10. According to the nitriding catalyst provided by the invention, the temperature of gas nitriding in nitrogen-containing atmospheres such as nitrogen or ammonia gas can be remarkably reduced.

Description

technical field [0001] The invention belongs to the field of chemical heat treatment, and relates to a catalyst for nitriding and its preparation and use method. Specifically, the catalyst can be used for surface nitriding of metal materials such as steel and titanium in a nitrogen-containing atmosphere such as nitrogen or ammonia. , reduce the nitriding temperature. 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 hardness, wear resistance, corrosion resistance and fatigue strength of the metal surface. 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 indust...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C8/24
Inventor 谢鲲孙金全夏鹏成曹梅青岳丽杰
Owner SHANDONG UNIV OF SCI & TECH
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