A kind of copper plate of crystallizer plating-thermal spraying complex gradient coating and preparation method thereof
Technical field
The present invention relates to a kind of coating of high-performance crystallizer, more particularly to a kind of copper plate of crystallizer plating-thermal jet
Apply complex gradient coating and preparation method thereof.
Background technology
Continuous casting has become production technology conventional in modern steel industrial production, shows that continuous casting billet yield reaches according to statistics
More than the 90% of crude steel yield, at the same time the use of high efficiency continuous casting machine is to conticaster cooling position:Crystallizer, it is proposed that higher
Performance requirement.Such as require high-bond, high-wearing feature, excellent thermal conductivity and good compactness etc..Therefore, Ke Yili
One layer of coating for meeting performance requirement is enclosed in crystallizer copper plate surface with surface engineering technology, so can both extend crystallizer
Service life can also reduce manufacturing cost.
At present, common technical method is the coating electroplated in crystalline copper plate surface to prepare required performance, such as hard
Cr coating, Ni-Fe coating, Ni-Co coating, Ni-Cr composite deposites and Ni-Co-W coating.Although electrodeposited coating and copper plate base body
It is higher with reference to power, but since its relatively low hardness causes that its wearability is poor, and service life is shorter.In addition, by NiCr-
Although the coating that Cr3C2 powder is directly prepared on Copper substrate using supersonic flame spraying with very high hardness with it is wear-resisting
Property, but since the difference of larger thermal coefficient of expansion can cause the combination power of coating and matrix very low, using process
In easily there is situation about peeling off, influence production efficiency increase production cost.Meanwhile copper plate of crystallizer is extremely severe in operating condition
Carve, the side of copper coin is contacted with 30~40 DEG C of cooling water, and opposite side is contacted with 1570 DEG C of molten steel, it is therefore desirable to which coating is being protected
Also to ensure that coating has good thermal conductivity while demonstrate,proving high bond strength, ensure the timely transmission of heat.
HVOF coatings have high hardness, but differ bigger with the physical property of copper plate base body, therefore limit HVOF paintings
Application of the layer on copper plate of crystallizer.So single HVOF coatings cannot meet that the performance of crystallizer is met the requirements, it is main
If it is larger that NiCr-Cr3C2 coatings and CrZrCu obtain difference of thermal expansion coefficients, so as to reduce HVOF coatings and copper plate base body knot
With joint efforts.It is inadequate only by adjusting spray parameters and coating composition to improve the combination power of HVOF coatings and copper plate base body.
The content of the invention
It is an object of the invention to overcome the deficiencies of the prior art and provide a kind of copper plate of crystallizer plating-thermal jet coating
Gradient coating and preparation method thereof is closed, improves combination power, hardness, heat conduction and the wear-resisting property of product.
The present invention is achieved by the following technical solutions, and complex gradient coating of the present invention includes being set in turn in base
Tack coat and working lining on body, described matrix are CrZrCu alloys, and tack coat is Ni layers, working lining NiCr-Cr3C2Layer;Institute
State NiCr-Cr3C2The interior tissue of layer includes NiCr solid solution phases, Cr3C2Carbide, Cr7C3Carbide and a small amount of amorphous phase.
The tack coat is electroplated Ni layer.Electroplating technology is ripe, suitable industrial production.
The NiCr-Cr3C2In layer, by mass percentage, including following components:NiCr 40~60%, Cr3C240~
60%.
One of preferred embodiment as the present invention, the thickness of the tack coat is 150~200 μm.
One of preferred embodiment as the present invention, the thickness of the working lining is 200~300 μm.
One of preferred embodiment as the present invention, complex gradient coating thermal conductivity at 500 DEG C reaches 90W/mK
More than.
A kind of preparation method of copper plate of crystallizer plating-thermal spraying complex gradient coating, comprises the following steps:
(1) bead again after CrZrCu alloy samples surface is polished, it is fixed after cleaning;
(2) sample after cleaning is positioned in electrolytic cell, the electroplated Ni layer on sample;
(3) after being polished with Ni layers of sample, then bead;
(4) after the sample after processing is fixed again, flame preheating, then carry out NiCr-Cr3C2The HVOF sprayings of layer.
In the step (1) and step (3), specimen surface is polished to roughness≤0.8 μm, then using alumina balls into
Row shot-peening, specimen surface roughness are 2~6 μm.
In the step (2), 40~80 DEG C, 10~20V of voltage, 3~7A/dm of current density of electroplating pool temperature2, during plating
Between 1~3h.
In the step (4), NiCr-Cr3C2In the spraying process of layer, kerosene oil flow is controlled in 23~27L/h, oxygen stream
Amount control controls matrix and tack coat table in 820~860NLPM, carrier gas flux control in 6.0~8.5NLPM, spraying process
Face mean temperature is 200~250 DEG C.
The present invention is accounted for from matrix-coat system, introduces the concept of complex gradient coating, i.e., in matrix and HVOF
Add one layer of tack coat between coating, so as to improve matrix in the combination power of coating and not influence the mechanicalness of HVOF working linings
Energy.Since Ni and copper plate base body have similar physical property, choose transition zone that Ni is tack coat most real value it
One.And the thermal coefficient of expansion of electroplated Ni tack coat is between matrix CrZrCu and NiCr-Cr3C2 working lining thermal coefficient of expansion, energy
Enough realize the transitional function of copper plate base body and the interlayer that works;The design of complex gradient coating can not only improve the combination power of coating
And compactness, and the wear rate of coating can be reduced.Due to the big characteristic of supersonic flame spraying flying speed of partcles, work
Layer compactness is good.
The present invention has the following advantages compared with prior art:The present invention is glued due to being sprayed at the electroplated Ni on copper plate base body surface
Tie the thermal coefficient of expansion of layer and hardness play the role of transition mitigation between NiCr-Cr3C2 working linings and matrix CrZrCu,
Each bed boundary physical property is mutually matched, therefore coating has compared with high-bond intensity;
Porosity in the present invention due to complex gradient coating is relatively low, compact structure, therefore has Thermal conductivity.This
Due to each layer hardness transition mitigation of complex gradient coating so that coating has good wear Characteristics, greatly in invention
The big wear rate for reducing coating;
Composite coating, which prepares completion, in the present invention need not carry out any post annealed processing, and bond strength reaches 75MPa,
Wear rate under 20N load is 1/10th of traditional electroplated Ni CoW, and largely improve copper plate of crystallizer uses the longevity
Life, at 500 DEG C, the thermal conductivity of complex gradient coating reaches more than 90W/mK, therefore it is broader to be beneficial to copper plate of crystallizer
Marketing development.
Brief description of the drawings
Fig. 1 is the SEM shape appearance figures that coating is made in embodiment 3;
Fig. 2 is that NiCr-Cr is made in embodiment 33C2The XRD diagram of layer;
Fig. 3 is the microhardness figure that coating coating under 500g load is made in embodiment 1~3;
Fig. 4 is the extension test figure that anchoring strength of coating is made in embodiment 1~3;
Fig. 5 is that coating friction and wear behavior figure is made in embodiment 1~3;
Fig. 6 is that thermal conductivity test chart of the coating at 500 DEG C is made in embodiment 1~3.
Embodiment
Elaborate below to the embodiment of the present invention, the present embodiment is carried out lower premised on technical solution of the present invention
Implement, give detailed embodiment and specific operating process, but protection scope of the present invention is not limited to following implementation
Example.
Embodiment 1
The CrZrCu copper alloy samples that market is bought are mechanically polished to surface roughness≤0.6 μm, using oxidation
Aluminium ball carries out shot-peening roughening treatment to 2~6 μm of surface roughness, then carries out acetone, absolute ethyl alcohol ultrasonic cleaning, Ran Houfang
Enter in alcohol and acetone, then with ultrasonic cleaning 30 minutes.Sample is placed in electroplating pool, electroplating solution component Ni 150~
500g/L, Co 3~13g/L of 20~150g/L, W, 40~80 DEG C, 10~20V of voltage, 3~7A/ of current density of electroplating pool temperature
dm2, 1~3h of electroplating time, gained electroplated Ni CoW layer thickness is 100~300 μm.
Embodiment 2
The CrZrCu copper alloys sample (block, rod) that market is bought is mechanically polished to surface roughness≤0.6 μm, is adopted
Shot-peening roughening treatment is carried out to 2~6 μm of surface roughness with alumina balls, then carries out acetone, absolute ethyl alcohol ultrasonic cleaning,
It is then placed in alcohol and acetone, first with ultrasonic cleaning 30 minutes, then with high pressure air rifle the sample after cleaning is dried up and consolidated
Due on supersonic spray coating equipment pivoted frame.Mechanical arm parameter is set, copper alloy matrix is preheated using flame, matrix table
Face temperature is 180~250 DEG C, and kerosene oil flow is controlled in 23~27L/h, and oxygen flux control is in 820~860NLPM, carrier gas stream
Amount control is in 6.0~8.5NLPM.Open powder valve and reset mechanical arm parameter, carry out NiCr-Cr3C2The spray of working lining
Apply.Spray time is 10~30min, and the single HVOF coatings that thickness is 250 μm are made on copper alloy matrix, then carry out machine
Tool is polished to roughness≤0.1 μm, and then progress acetone, absolute ethyl alcohol are cleaned by ultrasonic spare.
Embodiment 3
The CrZrCu copper alloys sample (block, rod) that market is bought is mechanically polished to surface roughness≤0.6 μm, is adopted
Shot-peening roughening treatment is carried out to 2~6 μm of surface roughness with alumina balls, then carries out acetone, absolute ethyl alcohol ultrasonic cleaning,
It is then placed in alcohol and acetone, then with ultrasonic cleaning 30 minutes.Sample is placed in electroplating pool, electroplating solution is amino sulphur
Sour nickel, nickel chloride, the mixed solution of dodecyl sodium, electroplating pool temperature 60 C, voltage 15V, current density 5A/dm2, during plating
Between 2h, gained electroplated Ni layer thickness be 180 μm.Above-mentioned preparation is had to the copper sample (block, rod) of electroplated Ni layer, is mechanically polished
To surface roughness≤0.6 μm, shot-peening roughening treatment is carried out to 2~6 μm of surface roughness using alumina balls, then carries out third
Ketone, absolute ethyl alcohol ultrasonic cleaning, are then placed in alcohol and acetone, then with ultrasonic cleaning 30 minutes.There is Ni to glue preparation
The sample of knot layer is fixed on supersonic spray coating equipment pivoted frame, sets mechanical arm parameter, is preheated using flame row, preheating temperature
150~200 DEG C, matrix surface and tack coat mean temperature are 220 DEG C, and kerosene oil flow control exists in 25L/h, oxygen flux control
840NLPM, carrier gas flux are controlled in 7.0NLPM.Open powder valve and reset mechanical arm parameter, carry out NiCr-Cr3C2's
Spraying.Spray time is 40min, and the NiCr-Cr that thickness is 250 μm is made3C2.Sample is removed, is mechanically polished to roughness
≤ 0.1 μm, then progress acetone, absolute ethyl alcohol are cleaned by ultrasonic spare.
Embodiment 4
The CrZrCu copper alloys sample (block, rod) that market is bought is mechanically polished to surface roughness≤0.6 μm, is adopted
Shot-peening roughening treatment is carried out to 2~6 μm of surface roughness with alumina balls, then carries out acetone, absolute ethyl alcohol ultrasonic cleaning,
It is then placed in alcohol and acetone, then with ultrasonic cleaning 30 minutes.Sample is placed in electroplating pool, electroplating solution is amino sulphur
Sour nickel, nickel chloride, the mixed solution of dodecyl sodium, 40 DEG C, voltage 10V, current density 3A/dm of electroplating pool temperature2, during plating
Between 1h, gained electroplated Ni layer thickness be 100 μm.Above-mentioned preparation is had to the copper sample (block, rod) of electroplated Ni layer, is mechanically polished
To surface roughness≤0.6 μm, shot-peening roughening treatment is carried out to 2~6 μm of surface roughness using alumina balls, then carries out third
Ketone, absolute ethyl alcohol ultrasonic cleaning, are then placed in alcohol and acetone, then with ultrasonic cleaning 30 minutes.There is Ni to glue preparation
The sample of knot layer is fixed on supersonic spray coating equipment pivoted frame, sets mechanical arm parameter, is preheated using flame row, matrix surface and
Tack coat mean temperature is 200 DEG C, and kerosene oil flow control is controlled in 23L/h, oxygen flux control in 820NLPM, carrier gas flux
In 6.0NLPM.Open powder valve and reset mechanical arm parameter, carry out NiCr-Cr3C2The spraying of working lining.Spray time is
30min, is made the NiCr-Cr that thickness is 200 μm3C2Working lining.Sample is removed, is mechanically polished to roughness≤0.1 μm,
Then progress acetone, absolute ethyl alcohol are cleaned by ultrasonic spare.
Embodiment 5
The CrZrCu copper alloys sample (block, rod) that market is bought is mechanically polished to surface roughness≤0.6 μm, is adopted
Shot-peening roughening treatment is carried out to 2~6 μm of surface roughness with alumina balls, then carries out acetone, absolute ethyl alcohol ultrasonic cleaning,
It is then placed in alcohol and acetone, then with ultrasonic cleaning 30 minutes.Sample is placed in electroplating pool, electroplating solution is amino sulphur
Sour nickel, nickel chloride, the mixed solution of dodecyl sodium, conventional electroplating solution, 80 DEG C, voltage 20V of electroplating pool temperature, current density
7A/dm2, electroplating time 3h, gained electroplated Ni layer thickness is 200 μm.By above-mentioned preparation have electroplated Ni layer copper sample (block,
Rod), mechanically polished to surface roughness≤0.6 μm, shot-peening roughening treatment is carried out to surface roughness 2 using alumina balls
~6 μm, acetone, absolute ethyl alcohol ultrasonic cleaning are then carried out, is then placed in alcohol and acetone, then divided with ultrasonic cleaning 30
Clock.The sample that preparation there are Ni tack coats is fixed on supersonic spray coating equipment pivoted frame, mechanical arm parameter is set, utilizes flame row
Preheating, matrix surface and tack coat mean temperature are 250 DEG C, and kerosene oil flow control exists in 27L/h, oxygen flux control
860NLPM, carrier gas flux are controlled in 8.5NLPM.Open powder valve and reset mechanical arm parameter, carry out NiCr-Cr3C2Work
Make the spraying of layer.Spray time is 50min, and the NiCr-Cr that thickness is 300 μm is made3C2Working lining.Sample is removed, carries out machinery
Roughness≤0.1 μm is polished to, then progress acetone, absolute ethyl alcohol are cleaned by ultrasonic spare.
As shown in Figure 1, Fig. 1 is the SEM schematic diagrames that coating is made in embodiment 3, it is followed successively by NiCr- in figure from top to bottom
Cr3C2Working lining, Ni tack coats and CrZrCu basic units, are tightly combined.
NiCr-Cr3C2In layer, by mass percentage, including following components:NiCr 50%, Cr3C250%.Such as Fig. 2 institutes
Show, NiCr-Cr3C2The interior tissue of layer includes NiCr solid solution phases, Cr3C2Carbide, Cr7C3Carbide and a small amount of amorphous phase.
NiCr belongs to metal solid solution phase, has good thermal conductivity, elastoplasticity and high-temperature oxidation resistance, and carbide is gold
Belong to ceramic phase there is very high hardness, play the role of in the coating support strengthen so that coating have preferable wearability with
Bond strength.
Coating made from embodiment 1~3 is subjected to microhardness detection, extension test, friction and wear behavior test, as a result
It is as follows:
Wherein, NiCoW is sample prepared by embodiment 1, and working lining prepares sample for embodiment 2, and tack coat-working lining is
Embodiment 3 prepares sample.
As shown in figure 3, NiCoW hardness prepared by embodiment 1 is relatively low, the coating prepared by embodiment 2 and embodiment 3 contains
A certain amount of carbide Cr3C2, therefore the working lining sample coatings case hardness prepared in embodiment 2 is glued with prepared by embodiment 3
Knot layer-working lining sample coatings case hardness maintains an equal level.
As shown in figure 4, the work that NiCoW samples tensile strength prepared by embodiment 1 is prepared in 32MPa or so, embodiment 2
The tensile strength of layer sample is minimum, and about 15MPa, the tensile strength of transition zone-working lining sample prepared by embodiment 3 substantially carries
Rise, about 75MPa.This is because NiCr-Cr3C2Powder differs larger with copper-based isolator CTE, can not be with spraying process
Copper alloy matrix combines very well, and Ni and Copper substrate and NiCr-Cr3C2The thermal coefficient of expansion of powder all relatively, therefore can
In matrix and NiCr-Cr3C2Play the role of a transition between working lining to relax, greatly improve complex gradient coating
Bond strength.
As can be seen from Figure 5 the NiCoW sample wear rates that prepared by embodiment 1 are about 3.5 × 10-13m3/ Nm, embodiment 2
The working lining sample wear rate of preparation is 2.0 × 10-13m3/ Nm, plating-working lining sample wear rate prepared by embodiment 3 are about
0.7×10-13m3/ Nm, reason is that electroplated Ni tack coat has preferable elastoplasticity, therefore the addition of Ni tack coats to grind
Loss rate reduces.
As shown in fig. 6, the NiCoW electrodeposited coatings of the preparation of embodiment 1 thermal conductivity 107W/mK, embodiment 2 at 500 DEG C are made
Standby working lining coating thermal conductivity 88W/mK at 500 DEG C, plating-working lining coating prepared by embodiment 3 heat at 500 DEG C
Conductance 94W/mK.If adding respective matrix, thermal conductivity rate score can increased again.Belong to metal mainly due to NiCr
Solid solution phase, has good thermal conductivity.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all essences in the present invention
All any modification, equivalent and improvement made within refreshing and principle etc., should all be included in the protection scope of the present invention.