TWI432604B - Application of the method of plasma spray coating - Google Patents

Description

Plasma spray coating method applied to pots

The invention relates to a plasma spray coating method applied to a pot, which is made of stainless steel or aluminum alloy as a substrate, and is coated with a layer of iron which is uniformly conductive and has iron release on the surface of the food contact [inner pot]. Layer.

Although the cast iron cookware has uniform heat conduction, long-lasting heat preservation and release of iron ions during cooking, it will contribute to health and many other advantages, but it has the problems of heavy weight and prone to thermal cracking. At present, the stainless steel and aluminum alloy pots on the market have the problems of solving thermal cracking and light weight, but the pots of the two materials have poor thermal conductivity and are not easy to uniformly heat transfer, resulting in more energy consumption and easy Deformation, contact with acidic substances and easy release of aluminum ions may affect health and other issues. Therefore, if the advantages of the above various pot materials can be effectively combined, a pot that saves energy and balances health can be obtained. Based on this, the Republic of China New Patent Application No. 076106147 discloses a method and apparatus for physical vapor deposition using cathodic arc plasma deposition techniques for decorative functional components (substrates) at very low temperatures. A hard coat layer is deposited [temperature range from about 50 ° C to about 500 ° C). The membrane consists of at least one of titanium, zirconium, titanium-zirconium, titanium-aluminum nitride, carbide and carbonitrides systems and their doped systems. In the apparatus and method of the present invention, a cathode arc source is used to evaporate metal in a vacuum chamber into which a low pressure gas or a doping gas is to be injected to form a hard coat layer on the surface of the substrate, wherein the arc source may be pulsed. The deposition method of the present invention is enhanced at very low basis Reproducibility and wear resistance of the color temperature (greater than or equal to about 50 ° C). The solidity of the coating can be further enhanced by a suitable biasing matrix. The film composition and thus the color can be suitably adjusted to eliminate the use of gold in decorative applications.

At present, there are two main methods for producing cast iron powder for spraying. One is to use pulverized ductile iron (FCD 450) turning machined chips to be pulverized and sieved to analyze powder particle size distribution, powder type and flow. The effect of the properties on the bonding strength of the hot melt coating shows that the smaller the particle size, the higher the carbon content of the cast iron powder, and the larger the particle size, the carbon content is much lower than the raw material (FCD450), and the particle size. The distribution of powders in the range of less than 32 μm is most dispersed, while the distribution of powders having particle sizes between 106 μm and 150 μm is concentrated. In addition, for the coating obtained by thermal spraying of the cast iron powder, the bonding strength results show that the bonding strength is the same as that of the commercially available molten powder for spraying, mainly due to the pulverization. The cast iron powder has a slender and flat shape, so that the powder is in a good molten state, and the formed coating has high stability. The other is cast iron powder [22-24] made by gas atomization, which has a spherical shape and a particle size of about 53 μm. It is coated with cast iron by high-velocity oxy fuel spraying. The effect of spraying distance on the hardness and wear of the coating is discussed. The results show that the hardness of the coating decreases with the increase of the spraying distance, and the wear loss of the coating abrasive increases and the wear resistance decreases. In addition, no graphite phase was found in the spray coating after each spray distance; and the cast iron powder before spraying or the cast iron coating after spraying was 800. After graphitization heat treatment at °C, the graphite phase can be observed in the cast iron coating. An aluminum-containing cast iron powder (Fe-3.75 wt% C-3.60 wt% Si-3.93 wt% Al) made by Tsunekawa et al. using water atomized, which has a relatively irregular appearance and a particle size of about 32 to 45 μm. And the oxygen content is higher than that of the cast iron powder produced by the gas spray method. The analysis of the coating of the aluminum-containing cast iron powder by atmospheric plasma shows that in the spray coating of the aluminum-containing cast iron powder without heat treatment, even The powder has a high content of graphitization elements (aluminum and tantalum) of cast iron, and the graphite phase is not found in the coating. The corrosion behavior of the coating in an acidic solution was analyzed. The results show that the corrosion resistance is related to the porosity of the coating, and the spray coating of the preheated cast iron powder, which is precipitated by the graphite phase of the coating, can increase the local corrosion. impedance.

The biggest drawbacks of the above techniques are:

1. The traditional cast iron cookware is heavier in weight and is prone to brittle cracking when falling.

2. Traditional stainless steel and aluminum alloy pots have problems such as poor thermal conductivity, difficulty in uniform heat transfer, energy consumption, easy deformation, and easy release of aluminum ions that may affect health.

3. The surface of traditional stainless steel and aluminum alloy cookware, which is spray coated with cast iron powder, consumes more energy and time and is more expensive in the process.

The aforementioned reference to the conventional pot coating technology, although it can achieve the basic requirements and effects of increasing and improving the application of surface mechanical and chemical properties, the process adaptability in practical application, In terms of technical efficiency, economic benefits, and industrial application specificity, there are many shortcomings and deficiencies, and it is impossible to exert more specific industrial applicability.

The invention solves the defects of the process adaptability, the technical efficiency, the economic benefit and the specificity of the industrial application, and the limitation of the practical technology in the conventional pot coating technology, and achieves the coating performance on the one hand. The primary purpose of enhancing the application of economic value is to improve the performance, suitability and application range of the efficiency and recycling life of the raw materials, the simplification of the structural design and the weight reduction. In addition to achieving the basic functions of adding and improving surface mechanical and chemical properties, and making it both practical and practical for industrial application.

Therefore, regardless of the subjective and objective conditions, the technology of the plasma spray coating method applied to the pot has no relevant and simple environmental protection and good coating characteristics in the current domestic and foreign patents. The structural technology, and the effective application in the field, has the advantage of the irreplaceable technology in the market, and is very suitable for the equipment market such as the surface coating industry of pots, which is bound to bring the surface of the pot plasma spray coating. It is a great business opportunity to cover the market related to industrial equipment production and manufacturing industry.

The invention effectively combines the advantages of using various pot materials, and obtains a pot that saves energy and takes care of the concept of health. Based on this, the present invention utilizes a plasma spray method to coat a cast iron coating having a uniform heat conductivity on a surface of a substrate such as 304 stainless steel or 5083 aluminum alloy. Due to cutting in the foundry In the process of cast iron, a large amount of chips will be generated, and if these pieces of graphite or ductile iron castings can be made into molten iron for spraying, the application value can be improved and the purpose of resource recovery can be achieved.

Accordingly, the present invention provides a plasma spray coating method for use in a cookware, wherein the plasma spray coating method applied to the cookware comprises:

a. Sawing: The initial cast iron powder is produced by sawing in the process of sawing cast iron.

b. Screening: The initial cast iron powder is passed through a sieving procedure to obtain cast iron powders of different particle size ranges, which are in the form of flakes or spheres.

c. Graphitization: The cast iron powder is heat treated by graphitization to promote the precipitation of the graphite phase of the cast iron coating.

d. Plasma spray: The cast iron powder is subjected to a plasma spray process to form a cast iron coating on the surface of the base material of the cookware.

By means of plasma spray coating, the cast iron coating on the surface of the pot has high mechanical strength, such as high bonding strength, abrasion resistance and corrosion resistance, to form a protective layer of the pot.

The specific features and effects of the present invention are as follows:

1. The cast iron powder produced by the industrial sawing process can produce cast iron powder in a more energy-saving and time-saving manner, without additional process, and achieve the purpose of resource recovery.

2. The initial cast iron powder with different particle sizes can be obtained by controlling the cutting conditions, and the cast iron powder for different particle size ranges can be obtained through the sieving method.

3. Development by economical method and melting technology of cast iron powder With the establishment of conditions, it can be developed into other applications that require graphite lubrication (such as lightweight sliders on the surface or aluminum alloy brake discs with surface-sprayed cast iron).

4. Through the graphitization heat treatment of the cast iron coating, a uniform thermal conductive structure layer containing a larger graphite phase can be obtained.

5. The cast iron coating has a graphite phase precipitated to increase the local corrosion resistance.

6. Preservation of the heat conduction of the cast iron pot is uniform, the insulation is long lasting, and the iron ions that contribute to health are released during the cooking process.

7. By the microstructure analysis of the coating, characteristics such as bonding strength and material damage can be obtained.

As shown in the first figure, the plasma spray coating method applied to the cookware includes:

a. Sawing: The initial cast iron powder is produced by sawing in the process of sawing cast iron. Referring to the fifth figure, the appearance of the cast iron powder is shown.

b. Screening: The initial cast iron powder is passed through a screening process to obtain cast iron powders of different particle size ranges. The cast iron powder subjected to the screening process is in the form of flakes or spheres; and at the same time, referring to the tenth figure, it is sieved through different sieves. After the ink and spheroidal graphite cast iron powder profile.

c. Graphitization: The cast iron powder is heat treated by graphitization to promote the precipitation of the graphite phase of the cast iron coating.

d. Plasma spray: the cast iron powder is subjected to a plasma spray process, and at the same time, refer to the sixth figure, which is a diagram of the plasma sprayed cast iron coating pot, forming a cast iron coating on the surface of the base of the pot, and then Referring to the eleventh figure, the use The cast iron powder obtained by sawing is subjected to a physical appearance of a plasma spray coating.

By means of plasma spray coating, the cast iron coating on the surface of the pot has high mechanical strength of bonding strength, abrasion resistance and corrosion resistance to form a protective layer of the pot; also refer to the twelfth and thirteenth Fig. is a cross-sectional SEM observation of spheroidal powders of different particle sizes by plasma spraying on various substrates (304 stainless steel, 5083 aluminum alloy and Al-12wt% Si alloy) and plasma powder of different particle sizes by plasma The microstructure of the coating sprayed onto various substrates.

As shown in the second figure, the coating material (the cast iron coating (2) which is a cast iron powder by plasma spraying) is based on the substrate (1) (1A) [may be 304 stainless steel or 5083 aluminum alloy, which is The surface roughness of the preferred embodiment of the pan substrate is selected as the bonding basis to form the desired bonding strength (see also the third and fourth figures), and the composition of the coating material is substantially particle (partical). ), between the particles, oxides, pores, voids, and the like.

As shown in the third figure, the pot is made by applying the plasma spray coating method (see also the step flow of the first figure), which is made of 304 stainless steel as the base material of the pot (1), and The cast iron coating (2) is coated and bonded to the surface of the base material (1) of the inner layer of the cookware to form a protective layer on the inner surface of the cookware; and referring to the seventh and eighth figures, respectively, the plasma sprayed cast iron coating The appearance of the stainless steel pot and the cross-section of the plasma spray test piece [304 stainless steel substrate + cast iron powder].

As shown in the fourth figure, apply the plasma spray coating method [see also The process of the first step is a pot made of a base material (1A) of 5083 aluminum alloy and coated with a cast iron coating (2) and bonded to the inner layer of the cookware. (1A) Surface, forming the protective layer on the inner pot surface of the cookware; also refer to the seventh and ninth figures, respectively, for the appearance of the plasma sprayed cast iron coated stainless steel pot and the cross-section observation of the plasma sprayed test piece [5038] Aluminum alloy substrate + cast iron powder].

In summary, the present invention is directed to a technique for applying a plasma spray coating method for a cookware, and particularly to a cast iron powder having a specific particle size obtained by sieving by using initial cast iron chips produced by sawing. The graphitization heat treatment is carried out, and finally the cast iron powder is coated on the inner pot surface of the 304 stainless steel (1) or 5083 aluminum alloy as the base material (1A) by a plasma spray technique to form a cast iron coating (2) The special protection layer, as a best improvement and design, is the most specific advancement of the invention for the plasma spray coating method applied to the pot.

(1) (1A) ‧‧‧Substrate

(2)‧‧‧ cast iron coating

The first figure is a flow chart of the plasma spray coated cast iron coating of the present invention.

The second figure is a schematic diagram of the plasma spray coating of the present invention in combination with a substrate.

The third figure is a schematic view of the surface of the 304 stainless steel substrate coated with cast iron coating of the present invention.

The fourth figure is a schematic view of the surface coated with cast iron coating of the 5083 aluminum alloy substrate of the present invention.

The fifth picture shows the appearance of cast iron powder.

The sixth picture shows the situation of the plasma sprayed cast iron coating pot.

The seventh picture shows the appearance of the plasma sprayed cast iron coated stainless steel pot.

The eighth picture is a cross-sectional observation of the plasma spray test piece [304 stainless steel substrate + cast iron powder].

The ninth picture is a cross-sectional observation of the plasma spray test piece [5083 aluminum alloy substrate + cast iron powder].

The tenth figure is a topographical view of the ink and spheroidal graphite cast iron powder screened by different screens.

The eleventh figure shows the physical appearance of the plasma spray coating by the cast iron powder obtained by sawing.

The twelfth image is a cross-sectional SEM observation of spheroidal powders of different particle sizes by plasma spraying on various substrates (304 stainless steel, 5083 aluminum alloy, and Al-12 wt% Si alloy).

The thirteenth picture shows the microstructure of the coating of different particle size spheroidal powders by plasma spraying on various substrates.

Claims (1)

A plasma spray coating method for a cookware, comprising: a. sawing: generating initial cast iron powder in a sawing process for sawing cast iron; b. sieving: passing initial cast iron powder through sieving The procedure is to obtain cast iron powder of different particle size range, the cast iron powder is in the form of flakes or spheres; c. graphitization: the cast iron powder is heat treated by graphitization to promote the precipitation of graphite phase of the cast iron coating; d. Spraying: cast iron powder is subjected to a plasma spraying process to form a cast iron coating on the surface of the base material of the pot; by means of a plasma spray coating, the cast iron coating on the surface of the pot has high bonding strength and resistance. Mechanical properties such as abrasion and corrosion resistance to form a protective layer for the pan.