Preparation method of nickel-molybdenum clad layer

A coating and nickel plate technology, applied in the direction of the electrode, etc., can solve the problems of decreased hardness of the coating, easy polymerization reaction, hindering the electroreduction of molybdenum, etc., and achieve the effect of increasing the hardness

Inactive Publication Date: 2012-04-11
SHANGHAI INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

During the preparation of nickel-molybdenum coatings, because molybdate ions are very sensitive, polymerization reactions are prone to occur, which will hinder the electroreduction of molybdenum, resulting in the reduction of the hardness of the coatings.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] A method for preparing a nickel-molybdenum coating specifically includes the following steps:

[0034] (1) Preparation of electroplating solution

[0035] In a 2L beaker, add 10g sodium molybdate, 10g sodium fluoride, 2g formic acid, 3g citric acid, 10g sodium chloride, add 950mL water to dissolve, form sodium molybdate-sodium fluoride-formic acid-citric acid-sodium chloride For the mixed solution, adjust the pH of the solution to 3 with a concentration of 10% (mass fraction) sodium carbonate aqueous solution, transfer it into a 1L volumetric flask, and dilute to the mark with water to prepare a molybdenum-containing heteropolyacid salt and fluoride with a pH of 3 , Complexing agent and chloride electroplating solution;

[0036] (2) Pretreatment of plated parts

[0037] After polishing the plate to be nickel-plated with 0~6# metallographic sandpaper, rinse with tap water and deionized water; then ultrasonic degreasing, hot water cleaning, tap water rinse, deionized water rinse...

Embodiment 2

[0044] A method for preparing a nickel-molybdenum coating specifically includes the following steps:

[0045] (1) Preparation of electroplating solution

[0046] In a 2L beaker, add 800g ammonium phosphomolybdate, 100g potassium fluoride, 50g tartaric acid, 50g potassium chloride, 50g ammonium chloride, and 930mL water to dissolve to form ammonium phosphomolybdate-potassium fluoride-tartaric acid-potassium chloride -Ammonium chloride mixed solution, adjust the pH of the solution to 6 with 20% (mass fraction) sodium carbonate aqueous solution, transfer it into a 1L volumetric flask, dilute to the mark with water, and prepare a molybdenum-containing heteropoly acid with a pH of 6 Electroplating solution of salt, fluoride, complexing agent and chloride;

[0047] (2) Pretreatment of plated parts

[0048] After polishing the alloy plate to be nickel-plated with 0~6# metallographic sandpaper, rinse with tap water and deionized water; then ultrasonic degreasing, hot water cleaning, tap wate...

Embodiment 3

[0055] A method for preparing a nickel-molybdenum coating specifically includes the following steps:

[0056] (1) Preparation of electroplating solution

[0057] In a 2L beaker, add 200g ammonium molybdate, 200g molybdic acid, 200g ammonium fluoride, 100g oxalic acid, 300g ammonium chloride, add 930mL water to dissolve, form ammonium molybdate-molybdic acid-ammonium fluoride-oxalic acid-ammonium chloride For the mixed solution, adjust the pH of the solution to 5 with a concentration of 20% (mass fraction) sodium carbonate aqueous solution, transfer it into a 1L volumetric flask, and dilute to the mark with water to prepare a molybdenum-containing heteropolyacid salt and fluoride with a pH of 5 , Complexing agent and chloride electroplating solution;

[0058] (2) Pretreatment of plated parts

[0059] After grinding the parts to be plated with 0~6# metallographic sandpaper, rinse with tap water and deionized water; then ultrasonic degreasing, hot water cleaning, tap water rinse, deioni...

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Abstract

The invention discloses a preparation method of a nickel-molybdenum clad layer. The method comprises the following steps of: dissolving heteropolymolybdate, fluoride, a complexing agent and chloride into water, and regulating the pH value of a solution with sodium carbonate to obtain a plating solution containing the heteropolymolybdate, fluoride, complexing agent and chloride of the pH value 3-6; and putting a pretreated plating piece to be plated serving as a cathode and a nickel plate serving as an anode into the plating solution containing the heteropolymolybdate, fluoride, complexing agent and chloride of the pH value 3-6 for plating, flushing the plating piece with water, and drying in the air to obtain a plating piece which contains a nickel-molybdenum clad layer on the surface. The hardness of the finally-obtained nickel-molybdenum clad layer is increased remarkably, the thermal expansion coefficient falls, the final hardness is 550-600 HV, and the thermal expansion coefficient is 13*10<-6>-5.2*10<-6> K<-1>.

Description

technical field [0001] The invention relates to a preparation method of nickel-molybdenum coating. Background technique [0002] With the development of aero-engines towards higher thrust-to-weight ratios, the design inlet temperature of the engines continues to increase. The operating temperature of the first-stage engine blades with the thrust-to-weight ratio of 12-15 and 15-20 will reach 1400°C and 1600°C. The use of high-temperature structural material technology alone can no longer meet the urgent requirements of the rapid development of advanced aero-engines. The use of thermal barrier coating technology is currently the only feasible method to greatly increase the operating temperature of aero-engines. At present, most of the thermal barrier coatings that have been practically used are double-layer structures. The surface layer is a ceramic insulation layer, which is mainly used for heat insulation, corrosion resistance, erosion and erosion; the bottom layer is a met...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D3/56C25D17/10
Inventor 刘小珍罗一凡耿建强朱良伟
Owner SHANGHAI INST OF TECH
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