CN102965611A

CN102965611A - Method for spraying barium titanate high-dielectric coating by using plasma

Info

Publication number: CN102965611A
Application number: CN2012105097038A
Authority: CN
Inventors: 邓春明; 毛杰; 邓畅光; 刘敏; 周克崧
Original assignee: Guangzhou Research Institute of Non Ferrous Metals
Current assignee: Guangzhou Research Institute of Non Ferrous Metals
Priority date: 2012-12-04
Filing date: 2012-12-04
Publication date: 2013-03-13

Abstract

The invention provides a method for spraying a barium titanate high-dielectric coating by using plasma. The method is characterized by comprising the following steps of: removing oil from the surface of a matrix by adopting acetone and ultrasonically cleaning the surface of the matrix, and carrying out sand blasting roughening by adopting 24-60# fused alumina zirconia at a sand blasting pressure of 0.1-0.4MPa until the surface is uniformly rough, wherein pure BaTiO3 powder with a grain size of 10-50mu m is adopted, nitrogen is powder feeding carrier gas, the carrier gas flow is 3-8L/min, the powder feeding quantity is 15-40g/min, the spraying current is 300-600A, the voltage is 65-75V, the power is 20-45kW, the plasma gas argon flow is 40-50L/min, H2 flow is 6-10L/min, the standoff distance is 90-150mm, and the preheating temperature of the matrix is 80-200DEG C. The spraying process for preparing the coating is simple and feasible, and is high in production efficiency; and the prepared barium titanate coating has the characteristics of thickness being 60-500mu m, bonding strength being more than 20MPa, relative dielectric constant being 800-2500(100Hz) and direct current breakdown voltage being 4.5-10.0kV/mm, and can be widely applied to the preparation of strong dielectric layers of a ceramic capacitor and other insulation parts.

Description

The method of the high dielectric coat of a kind of plasma spraying metatitanic acid barium

Technical field

The present invention relates to the hot spray coating technology of preparing, particularly a kind of plasma spray system prepares the method for barium titanate high dielectric ceramic coating.

Background technology

BaTiO ₃Being the basic material of electron ceramic material, being called as the pillar of electronic ceramics industry, also is to use one of the widest, that consumption is maximum important source material in the electronic ceramics.BaTiO ₃Dissolve in the vitriol oil, hydrochloric acid and hydrofluoric acid, fusing point is 1625 ℃, and density is 6.08g/cm ³, relative molecular mass is 233.19.BaTiO ₃Crystalline form has Tetragonal, Emission in Cubic, oblique side's phase, tripartite phase and six sides mutually, and modal is the Tetragonal crystal.BaTiO ₃Premium properties mainly include high-k, low-dielectric loss, good ferroelectric, piezoelectricity, withstand voltage and insulating property etc., for example, BaTiO ₃Under the effect of DC electric field, can produce polarizing effect, become indispensable material in the high frequency circuit element.Forceful electric power also is used to medium amplification, frequency modulation and storage device simultaneously.Can utilize BaTiO ₃The electrical capacity of ceramic condenser changes this characteristic with bias voltage, controls exchange current by electrical condenser to amplify.

At present, using comparatively widely, the preparation method of barium titanate ceramics mainly contains three kinds: solid reaction process, sol-gel method, hydrothermal synthesis method.Solid reaction process is to prepare at present the most ripe method of barium titanate ceramics, mainly relies on solid phase diffusion mass transfer mode to react.With BaCO ₃, TiO ₂Be main raw material, through technological processs such as ball milling, moulding, sintering, can obtain the barium titanate ceramics block materials, but produce larger contraction during sintering, be difficult to guarantee dimensional precision behind the sintering.When using as workpiece, in order to guarantee the requirements such as morpheme dimensional precision and surface quality, also need it is carried out turning, cutting, grinding etc.Because stupalith is high hard, high crisp, the ceramic components shape becomes increasingly complex simultaneously, requirement to dimensional precision, surfaceness, reliability is more and more higher, and mechanical processing difficulty is increasing, and the mechanical workout affected layer directly has a negative impact to the performance of components and parts.

Summary of the invention

The plasma spraying that the present invention relates to belongs to hot-spraying techniques, is to be fit to the BaTiO of particle diameter ₃Powdered material is sent in the plasma jet, makes that powder particle accelerates therein, behind fusing or the partial melting, under the effect of surging force, sprawls and solidifies the formation synusia in substrate, and then form a class complete processing of coating by the synusia lamination.The core temperature of plasma spraying jet is up to more than 15000 K, and the material ranges of spraying is wide, is particularly useful for the preparation of the higher melt coated materials such as oxide ceramics, carbide metal-ceramic, can obtain in conjunction with good stratiform dense coating.Have simultaneously the advantages such as production efficiency height, cost is low, technique is simple, do not need precision turning, cutting etc., can increase as required follow-up grinding-polishing technique, can reach components and parts dimensional precision, surfaceness requirement, grinding-polishing does not have a negative impact substantially to the performance of components and parts after the spraying.

The object of the present invention is to provide a kind of method that adopts the air plasma spraying system to prepare barium titanate high dielectric ceramic coating.

The objective of the invention is following technical scheme and realize that concrete steps are as follows:

After matrix surface carries out acetone oil removing and ultrasonic cleaning, adopt 24 ~ 60 ^#Zircon corundum, blasting pressure 0.1 ~ 0.4MPa carries out the sandblast alligatoring, and is coarse to surface uniform; Use the pure BaTiO of particle diameter 10 ~ 50 μ m ₃Powder, nitrogen are the powder feeding carrier gas, carrier gas flux 3 ~ 8L/min, and powder sending quantity 15 ~ 40g/min, spraying current 300 ~ 600A, voltage 65 ~ 75V, power 20 ~ 45kW, plasma gas argon are 40 ~ 50L/min, H ₂Be 6 ~ 10L/min, the spray distance is 90 ~ 150mm, 80 ~ 200 ℃ of substrate preheating temperature.

Barium titanate coat-thickness 60 ~ 500 μ m of the inventive method preparation, bonding strength＞25MPa, relative permittivity are up to 800 ~ 2500 (100Hz), dc breakdown voltage 4.5 ~ 10.0kV/mm.

Utilize the BaTiO of plasma spraying technology preparation ₃Coating is the same with block materials, has high-k, the characteristics of low-dielectric loss, and its dielectric properties are suitable with room temperature barium titanate block materials.Be fit to preparation barium titanate ceramics laminate structure, particularly Direct precipitation coating on the components and parts complex profile, be used for the ceramic condenser of some particular design and complex construction as strong dielectric layer, or be applied to thermoelectricity, piezoelectric element etc. as the function ceramics layer.While BaTiO ₃Coating application potential aspect posistor (PTC), sonar, infrared detective element, electric light display panel, material with memory, semiconductor material, static transformer, dielectric amplifier, frequency transformer, storer and polymer matrix composite is huge.

Compare with existing barium titanate block materials preparation and forming technique, the present invention has following remarkable advantage:

1) the plasma spraying jet temperature is high, is applicable to the preparation of barium titanate ceramics coated material, and the barium titanate ceramics composition of layer is stable, produces without other impurity phase;

2) traditional ceramic parts of engine, particularly lamella or special shape, need to carry out to stupalith the mechanical workouts such as precision turning, cutting, grinding, but because stupalith is high hard, high crisp, mechanical workout is difficult to the machining shape complexity, dimensional precision is high, surfaceness is low, the workpiece of high reliability; It is simple that plasma spraying of the present invention prepares the barium titanate ceramics coating process, do not need precision turning, cutting etc., can increase as required follow-up grinding-polishing technique;

3) barium titanate coating and base material bonding strength＞25MPa, compact structure.Barium titanate ceramics coating specific inductivity is high, and dielectric loss is low, and is suitable with room temperature barium titanate block materials;

4) economical with materials;

5) the coating sedimentation effect is high, speed is fast, and about 25 ~ 35 μ m/ times, even thickness;

6) be fit to preparation barium titanate ceramics laminate structure, particularly Direct precipitation coating on complex profile, can be used as the ceramic condenser that strong dielectric layer is used for some particular design and complex construction, or be applied to thermoelectricity, piezoelectric element etc. as the function ceramics layer.

Description of drawings

Fig. 1 is the metallographic cross-section photograph of barium titanate coating on the stainless steel substrate, 1.BaTiO ₃Coating; 2. stainless steel base.

Fig. 2 is the XRD figure spectrum of barium titanate coating on the stainless steel substrate, ● Emission in Cubic BaTiO ₃▼ Tetragonal BaTiO ₃

Fig. 3 is the metallographic cross-section photograph of barium titanate coating on the graphite substrate, 1.BaTiO ₃Coating; 2. graphite matrix.

Embodiment

Embodiment 1

Present embodiment selects Stainless Steel Alloy as base material, and specific operation process is as follows:

After matrix surface carries out acetone oil removing and ultrasonic cleaning, adopt 24 ^#Zircon corundum, blasting pressure 0.3 MPa carries out the sandblast alligatoring, and is coarse to surface uniform, without metalluster; Use the pure BaTiO of particle diameter 10 ~ 30 μ m ₃Powder, adopting nitrogen is the powder feeding carrier gas, carrier gas flux 4L/min, powder sending quantity are controlled at about 25g/min, spraying current 450A, voltage 71V, power is controlled at 30 ~ 31kW, and the plasma gas argon is 47L/min, H ₂Be 8L/min, spray apart from be 80,100, three kinds of 120mm, the substrate preheating temperature is controlled at about 150 ℃.

The barium titanate coated component of present embodiment preparation is stable, is four directions and Emission in Cubic BaTiO ₃, without the mutually generation of decomposition or other composition, even thickness, coat-thickness is at 220 ~ 250 μ m on the flat panel substrates, and bonding strength is between 28 ~ 30MPa, and relative permittivity and dc breakdown voltage see Table 1.

The performance of the barium titanate coating of table 1 embodiment 1

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Embodiment 2

Present embodiment selects graphite as base material, and specific operation process is as follows:

After matrix surface carries out acetone oil removing and ultrasonic cleaning, adopt 60 ^#Zircon corundum, blasting pressure 0.2 MPa carries out the sandblast alligatoring, and is coarse to surface uniform; Use the pure BaTiO of particle diameter 10 ~ 45 μ m ₃Powder, adopting nitrogen is the powder feeding carrier gas, carrier gas flux 5L/min, powder sending quantity is controlled at 30g/min, spraying current 550A, voltage 72V, power is controlled at 39 ~ 40kW, and the plasma gas argon is 45L/min, H ₂Be 9L/min, spray apart from be 80,100, three kinds of 120mm, the substrate preheating temperature is controlled at about 100 ℃.

The barium titanate coat-thickness of present embodiment preparation is even, and coat-thickness is between 130 ~ 160 μ m on the plate graphite base material, and bonding strength is 25 ~ 28MPa, and relative permittivity and dc breakdown voltage see Table 2.

The performance of the barium titanate coating of table 2 embodiment 2

Claims

1. the method for the high dielectric coat of plasma spraying metatitanic acid barium is characterized in that step is as follows: after matrix surface carries out acetone oil removing and ultrasonic cleaning, adopt 24 ~ 60 ^#Zircon corundum, blasting pressure 0.1 ~ 0.4MPa carries out the sandblast alligatoring, and is coarse to surface uniform; Use the pure BaTiO of particle diameter 10 ~ 50 μ m ₃Powder, nitrogen are the powder feeding carrier gas, carrier gas flux 3 ~ 8L/min, and powder sending quantity 15 ~ 40g/min, spraying current 300 ~ 600A, voltage 65 ~ 75V, power 20 ~ 45kW, plasma gas argon are 40 ~ 50L/min, H ₂Be 6 ~ 10L/min, the spray distance is 90 ~ 150mm, 80 ~ 200 ℃ of substrate preheating temperature.