CN108002828B

CN108002828B - YSZ ceramic granulation powder for plasma spraying and preparation method thereof

Info

Publication number: CN108002828B
Application number: CN201711307384.1A
Authority: CN
Inventors: 宋希文; 谢敏; 包金小; 周芬; 郜建全; 张永和; 郭文荣
Original assignee: Inner Mongolia University of Science and Technology
Current assignee: Inner Mongolia University of Science and Technology
Priority date: 2017-12-11
Filing date: 2017-12-11
Publication date: 2020-07-28
Anticipated expiration: 2037-12-11
Also published as: CN108002828A

Abstract

The invention provides YSZ ceramic granulation powder for plasma spraying and a preparation method thereof, wherein YSZ clinker is obtained by mixing starch with mixed raw material containing yttrium oxide and zirconium oxide with the particle size of 0.5-4 mu m and roasting at 1350-1550 ℃; mixing the obtained YSZ clinker with a dispersant and water, and carrying out ball milling treatment to obtain ball milling slurry; and then, performing sanding treatment on the obtained clinker slurry to obtain sanding slurry, mixing the sanding slurry with a binder, and granulating to obtain YSZ ceramic granulation powder for plasma spraying. According to the invention, the solid-phase reaction of zirconia and yttria is realized in the high-temperature roasting process, so that zirconia (YSZ) with yttria partially stabilized is obtained, and the performance is stable; and acid radical ions are not introduced, the high-temperature roasting temperature is higher, the solid-phase reaction is fully carried out, and simultaneously, trace acid radical ions can be burnt out, so that the batch performance stability of the powder is improved.

Description

YSZ ceramic granulation powder for plasma spraying and preparation method thereof

Technical Field

The invention relates to the technical field of ceramic powder, in particular to YSZ ceramic granulation powder for plasma spraying and a preparation method thereof.

Background

The plasma spraying thermal barrier coating is widely applied to the fields of aviation, aerospace, machinery, military industry and the like, wherein Y is₂O₃Partially stabilized ZrO₂(YSZ) is today the most popular ceramic material for thermal barrier coatings due to its high melting point, low thermal conductivity, relatively high coefficient of thermal expansion and good corrosion resistance.

With the rapid development of scientific technology, the working conditions of the surfaces of high-temperature working condition components such as turbine blades, turbine combustors, hot end components of weapon equipment propulsion systems and the like are more and more severe, the performance of a thermal barrier coating obtained by plasma spraying conventional micron-sized ceramic powder is difficult to meet the requirements, and the nano-sized ceramic powder for plasma spraying is urgently needed.

At present, the YSZ nano ceramic powder for plasma spraying is mainly prepared by a coprecipitation method, the used raw materials are zirconium and yttrium salt substances such as zirconium oxychloride and yttrium nitrate, a large amount of polluting ions such as chloride ions, nitrate radicals and ammonium radicals are inevitably introduced, the polluting ions are dissolved in water to form a salt solution, then the salt solution is added into an alkaline solution such as ammonia water or sodium hydroxide, the zirconium hydroxide and yttrium hydroxide precipitate is generated through reaction, and then the subsequent calcination process at about 800 ℃ is combined to obtain the YSZ nano ceramic powder. However, a large amount of polluting ions are introduced by the coprecipitation method, a large amount of deionized water is needed in the washing process, environmental pollution is caused, the wastewater treatment cost is increased, partial acid radical ions are inevitably remained in the powder prepared by the coprecipitation method, the performance stability of the powder is seriously influenced, and the service life of the prepared thermal barrier coating is uneven.

Disclosure of Invention

In view of the above, the present invention aims to provide YSZ ceramic granulated powder for plasma spraying and a preparation method thereof, which does not need to use salts of zirconium and yttrium, avoids introduction of contaminating ions into raw materials, and can obtain YSZ ceramic granulated powder for plasma spraying with stable performance.

In order to achieve the above object, the present invention provides the following technical solutions:

a preparation method of YSZ ceramic granulation powder for plasma spraying comprises the following steps:

(1) providing a mixed raw material containing yttrium oxide and zirconium oxide; the particle size of the mixed raw material is 0.5-4 mu m;

(2) mixing the mixed raw material with starch, and roasting at high temperature to obtain YSZ clinker; the high-temperature roasting temperature is 1350-1550 ℃;

(3) mixing the YSZ clinker obtained in the step (2) with a dispersant and water, and carrying out ball milling treatment to obtain ball milling slurry;

(4) performing sanding treatment on the ball milling slurry obtained in the step (3) to obtain sanding slurry;

(5) and (4) mixing the sand grinding slurry obtained in the step (4) with a binder, and granulating to obtain YSZ ceramic granulation powder for plasma spraying.

Preferably, the mass ratio of the zirconium oxide to the yttrium oxide in the mixed raw material is (900-940): (60-100).

Preferably, the preparation method of the mixed raw material comprises the following steps: carrying out ball milling treatment and drying treatment on mixed slurry containing zirconium oxide, yttrium oxide, a dispersing agent and water in sequence to obtain mixed raw material containing yttrium oxide and zirconium oxide;

the mass ratio of the total mass of the zirconium oxide and the yttrium oxide to the water in the mixed slurry is (55-65): (35-45);

the ratio of the mass of the dispersing agent in the mixed slurry to the total mass of the zirconia and the yttria is 100 (0.20-1.0).

Preferably, the high-temperature roasting time in the step (2) is 2-6 h.

Preferably, the mass ratio of the starch to the mixed raw material in the step (2) is (2-6): 100.

preferably, the dispersant in step (3) is one or more of ammonium polyacrylate, sodium tripolyphosphate, sodium hexametaphosphate, ammonium polymethacrylate and polyethylene glycol;

the mass ratio of the dispersing agent to the YSZ clinker is (0.2-1.0): 100, respectively;

the mass ratio of YSZ clinker to water in the step (3) is (55-65): (35-45).

Preferably, the rotation speed of the ball milling treatment in the step (3) is 40-80 r/min, and the time of the ball milling treatment is 12-24 h.

Preferably, the rotation speed of the sand grinding treatment in the step (4) is 800-1200 r/min, and the time of the sand grinding treatment is 2-6 h.

Preferably, the amount of the binder used in the step (5) is calculated by the mass of the YSZ clinker in the sanding slurry, and the mass ratio of the YSZ clinker to the binder is 100 (0.3-1.5).

The invention also provides YSZ ceramic granulated powder for plasma spraying, which is prepared by the preparation method in the technical scheme and comprises the following components: 90-94 wt% of zirconium oxide and 6-10 wt% of yttrium oxide stabilizer; the grain size of the YSZ ceramic granulated powder is 30-150 mu m.

The invention provides a preparation method of YSZ ceramic granulation powder for plasma spraying, which comprises the following steps: mixing the mixed raw material containing yttrium oxide and zirconium oxide with the particle size of 0.5-4 mu m with starch, and roasting at 1350-1550 ℃ to obtain YSZ clinker; mixing the obtained YSZ clinker with a dispersant and water, and carrying out ball milling treatment to obtain ball milling slurry; and then, performing sanding treatment on the obtained clinker slurry to obtain sanding slurry, mixing the sanding slurry with a binder, and granulating to obtain YSZ ceramic granulation powder for plasma spraying.

According to the invention, the solid-phase reaction of zirconia and yttria is realized in the high-temperature roasting process to obtain yttria partially stabilized zirconia (YSZ), that is, yttria is dissolved in the crystal lattice of zirconia to obtain a mixed phase structure of tetragonal phase and cubic phase, and the structure is stable, so that the performance is stable. In addition, acid radical ions are not introduced, the high-temperature roasting temperature is higher, the solid-phase reaction is fully carried out, and simultaneously, trace acid radical ions remained in commercially available zirconium oxide and yttrium oxide can be burnt out, so that the defect of unstable powder performance caused by high acid radical ion content in the preparation process of the coprecipitation method is effectively overcome, and the batch performance stability of the powder is improved. The results of the embodiments show that the YSZ ceramic granulated powder for plasma spraying prepared by the invention has stable performance, so that the thermal barrier coatings prepared in the same batch have uniform service life.

Drawings

FIG. 1 is an XRD pattern of YSZ clinker obtained by sintering at 1450 ℃ for 4 hours in example 3 of the present invention;

FIG. 2 is a field emission scanning electron microscope image of YSZ ceramic powder obtained by sanding at 1100r/min for 3 hours in example 4 of the present invention;

FIG. 3 is an optical microscope photograph of YSZ ceramic granulated powder prepared in example 4 of the present invention;

FIG. 4 is a cross-sectional view of a thermal barrier coating a prepared by plasma spraying the YSZ granulated powder obtained in example 1 of the present invention;

FIG. 5 is a cross-sectional optical microscopic morphology of a thermal barrier coating b prepared by plasma spraying of YSZ granulated powder obtained in example 1 of the present invention;

FIG. 6 is a cross-sectional optical microscopic morphology of a thermal barrier coating c prepared by plasma spraying of YSZ granulated powder obtained in example 1 of the present invention;

fig. 7 is an optical microscopic morphology image of a cross section of a thermal barrier coating d prepared by subjecting YSZ granulated powder obtained in example 1 of the present invention to plasma spraying.

Detailed Description

The invention provides a preparation method of YSZ ceramic granulation powder for plasma spraying, which comprises the following steps:

The mixed raw material containing the yttrium oxide and the zirconium oxide provided by the invention is characterized in that the mass ratio of the zirconium oxide to the yttrium oxide in the mixed raw material is preferably (900-940): (60-100), more preferably (915-935): (65-85), more preferably 930: 70. in the present invention, the particle size of the raw mix is 0.5 to 4 μm, preferably 1 to 3 μm, and more preferably 1.5 to 2 μm.

In the present invention, the method for preparing the mixed raw material preferably includes: and performing ball milling treatment and drying treatment on the mixed slurry containing the zirconium oxide, the yttrium oxide, the dispersing agent and water in sequence to obtain a mixed raw material containing the yttrium oxide and the zirconium oxide.

The source of the zirconia and yttria is not particularly required in the present invention, and commercially available products of zirconia and yttria known to those skilled in the art may be used. In the invention, the mass ratio of the total mass of zirconia and yttria to water in the mixed slurry is preferably (55-65): (35-45), more preferably (56-62): (38-44), more preferably (58-61): (39-42), most preferably 60: 40.

in the present invention, the dispersant for preparing the mixed raw material is preferably one or more of ammonium polyacrylate, sodium tripolyphosphate, sodium hexametaphosphate, ammonium polymethacrylate and polyethylene glycol. When a plurality of dispersants are selected, different kinds of dispersants are preferably added in equal parts by mass in the present invention. The source of the dispersant is not particularly critical to the present invention and may be any source known to those skilled in the art.

In the present invention, the ratio of the mass of the dispersant to the total mass of the zirconia and the yttria in the mixed slurry is preferably 100 (0.20 to 1.0), and more preferably 100: (0.25 to 0.85), more preferably 100: (0.5-0.55). In the invention, the dispersant is organic matter, and the usage amount is less, and the disadvantage of introducing acid radical ions is avoided.

According to the invention, the mixed slurry is preferably subjected to ball milling treatment and drying treatment in sequence to obtain the mixed raw material containing yttrium oxide and zirconium oxide. In the invention, the rotation speed of the ball milling treatment is preferably 120-160 r/min, more preferably 125-155 r/min, and even more preferably 130-140 r/min. In the invention, the time of the ball milling treatment is preferably 2 to 6 hours, more preferably 2.5 to 5.5 hours, and even more preferably 3 to 5 hours. In the present invention, the milling bodies used for the ball milling are preferably zirconia balls; the particle size of the grinding body is preferably 3-8 mm, more preferably 3.5-7 mm, and even more preferably 4-5 mm.

In the present invention, the ball-milling treatment is preferably carried out in a ball mill; the ball mill is preferably a stirred ball mill or a roller mill.

In the invention, the ball milling can realize the refinement of the zirconia and the yttria, so that the mixed raw material containing the zirconia and the yttria with the target grain diameter can be conveniently obtained, and further, the solid-phase reaction is ensured to be carried out in the subsequent roasting process; and the ball milling is helpful for uniform mixing of the zirconium oxide and the yttrium oxide, so that the subsequent solid-phase reaction can be fully carried out.

After the ball milling treatment, the ball milling slurry is preferably dried to obtain a mixed raw material containing yttrium oxide and zirconium oxide. In the present invention, the water content of the mixed raw material is preferably 0.5 wt% or less. In the present invention, the drying treatment is preferably one or more of spray drying, electric oven drying, evaporator drying, centrifugal dewatering and filter-press dewatering. The present invention does not require special embodiments of the centrifugal dewatering and filter-press dewatering, and can be implemented as is well known to those skilled in the art. In the invention, when an electrothermal oven drying or evaporator drying mode is adopted, the drying treatment temperature is preferably 80-100 ℃, more preferably 85-95 ℃, and more preferably 90-95 ℃; the drying time is preferably 5 to 15 hours, more preferably 8 to 12 hours, and even more preferably 9 to 10 hours. In the present invention, when the spray drying method is adopted, the atomization frequency of the spray drying is preferably 40 to 50Hz, and more preferably 45 Hz. In the invention, the air inlet temperature of the spray drying is preferably 220-250 ℃, and more preferably 230-240 ℃; the air outlet temperature of the spray drying is preferably 85-100 ℃, and more preferably 90-95 ℃. The present invention does not require any particular manner of spray drying, and spray drying known to those skilled in the art may be employed.

After the mixed raw material is obtained, the mixed raw material is mixed with starch and is roasted at high temperature to obtain YSZ clinker.

In the invention, the mass ratio of the mixed raw material to the starch is preferably (2-6): 100, more preferably (2.5 to 5.5): 100, more preferably (3 to 4.5): 100. the source of the starch is not particularly required in the present invention, and starches known to those skilled in the art can be used. After the starch and the mixed raw material are mixed, the starch can be decomposed and volatilized in the high-temperature roasting process, air holes are left, the material can be effectively prevented from being blocked, and the YSZ clinker can be refined in the subsequent ball-milling process.

The present invention has no special requirements for the mixing manner of the mixed raw material and starch, and the material mixing manner known to those skilled in the art is adopted to realize uniform mixing of the mixed raw material and starch.

After the mixing is finished, the YSZ clinker is obtained by roasting the mixture at high temperature. In the invention, the high-temperature roasting temperature is 1350-1550 ℃, preferably 1400-1500 ℃, and further preferably 1420-1480 ℃; in embodiments of the invention, the firing temperature is specifically 1370 ℃, 1410 ℃, 1430 ℃, 1470 ℃ or 1520 ℃. In the invention, the roasting time is preferably 2-6 h, and more preferably 3-5 h; in the embodiment of the invention, the roasting time is specifically 2.5h, 3.5h, 4.0h, 4.5h or 5.5 h. According to the invention, the solid-phase reaction of zirconia and yttria is realized in the high-temperature roasting process to obtain yttria partially stabilized zirconia (YSZ), that is, yttria is dissolved in the crystal lattice of zirconia to obtain a mixed phase structure of tetragonal phase and cubic phase, and the structure is stable, so that the performance is stable; the high-temperature roasting temperature is high, so that trace acid radical ions remained in commercially available zirconium oxide and yttrium oxide can be burnt out while solid-phase reaction is fully carried out, and the influence of the acid radical ions on the service life of the thermal barrier coating is avoided; the high-temperature roasting can also avoid excessive hardening of the roasted material and excessive growth of particles caused by overhigh temperature.

After the high-temperature roasting, the YSZ clinker is mixed with a dispersant and water, and ball milling treatment is carried out to obtain ball milling slurry. In the invention, the dispersant is preferably one or more of ammonium polyacrylate, sodium tripolyphosphate, sodium hexametaphosphate, ammonium polymethacrylate and polyethylene glycol; the particular source of the dispersant of the present invention is not particularly limited and commercially available products known to those skilled in the art may be used. In the present invention, the water is preferably distilled water or deionized water.

In the invention, the mass ratio of the dispersing agent to YSZ clinker is preferably (0.2-1.0): 100, more preferably (0.3 to 0.9): 100, more preferably (0.5 to 0.7): 100. in the invention, the mass of the YSZ clinker is preferably 55-65%, more preferably 58-62%, and even more preferably 60-61% of the total mass of the YSZ clinker and water.

The mixing mode of the YSZ clinker, the dispersing agent and the water does not have special requirements, and the mixing mode of the materials and the water which is well known by the technical personnel in the field can be adopted.

After the mixing, the invention carries out ball milling treatment on the mixed clinker slurry to obtain ball-milled slurry. In the invention, the rotation speed of the ball milling treatment is preferably 40-80 r/min, more preferably 45-75 r/min, and more preferably 50-60 r/min; the time of the ball milling treatment is preferably 12 to 24 hours, more preferably 15 to 20 hours, and even more preferably 16 to 18 hours. In the present invention, the milling bodies used for the ball milling are preferably zirconia balls; the particle size of the grinding body is preferably 10-30 mm, more preferably 15-28 mm, and even more preferably 20-25 mm.

In the invention, the starch can be decomposed and volatilized in the high-temperature roasting process, air holes are left, the material can be effectively prevented from being agglomerated, the effective refining of YSZ clinker in the ball milling process is facilitated, the energy consumption is reduced, and the smooth proceeding of the ball milling process can be ensured.

In the present invention, the particle size of the YSZ clinker in the ball-milled slurry of the YSZ clinker after ball milling is preferably 4 μm or less, and more preferably 0.5 to 4 μm.

The invention has no special requirements on the specific mode of ball milling treatment, and the mode of ball milling treatment which is well known to those skilled in the art can be adopted.

After the ball milling treatment, the obtained ball milling slurry is subjected to sand milling treatment to obtain sand milling slurry. Before the sanding treatment, the mass ratio of YSZ clinker to water in the ball-milling slurry is preferably adjusted to obtain slurry for the pre-sanding treatment; the mass of YSZ clinker in the slurry for pre-sanding treatment is 45-55% of the total mass of YSZ clinker and water, more preferably 46-52%, and still more preferably 48-50%. In the present invention, the adjustment of the mass ratio is preferably achieved by the addition of water.

In the invention, the rotation speed of the sanding treatment is preferably 800-1200 r/min, more preferably 850-1150 r/min, more preferably 900-1100 r/min, and most preferably 1000-1050 r/min. In the invention, the sanding treatment time is preferably 2-6 h, more preferably 2.5-5.5 h, even more preferably 3-5 h, and most preferably 4-4.5 h. In the present invention, the abrasive body used for the sanding is preferably zirconia balls; the particle size of the abrasive is preferably 0.1 to 0.8mm, more preferably 0.2 to 0.5mm, and still more preferably 0.3 to 0.4 mm.

In the present invention, the sanding treatment is preferably carried out in a sand mill; the invention has no special requirement on the source of the sand mill, and the sand mill which is well known by the technical personnel in the field can be adopted; in the embodiment of the present invention, the type of the sand mill is determined according to the total amount of slurry required to be sanded.

In the present invention, the grain size of the YSZ clinker in the sand grinding slurry is preferably 100nm or less, and more preferably 80nm or less.

The present invention does not require any particular manner of sanding as will be appreciated by those skilled in the art.

In the high-temperature roasting process, the processes of hardening and grain growth of the material exist, and the advantages of sanding treatment can be fully exerted through a ball-milling and sanding treatment mode, so that the roasting material is refined.

After the sanding treatment, the obtained sanding slurry is mixed with a binder for granulation, and YSZ ceramic granulation powder for plasma spraying is obtained. The invention does not require any particular kind of binder, and a binder for ceramics known to those skilled in the art may be selected, such as polyvinyl alcohol. In the invention, the amount of the binder is preferably 100 (0.3-1.5), more preferably 100 (0.4-1.2), even more preferably 100 (0.5-1.0), and even more preferably 100 (0.75-0.8), based on the mass of the YSZ clinker in the sanding slurry.

The present invention does not require any particular mixing of the sanding slurry and binder, and can be accomplished by any means known to those skilled in the art.

The slurry obtained by mixing is granulated to obtain YSZ ceramic granulated powder for plasma spraying. In the present invention, the granulation is preferably spray granulation. In the present invention, the atomization frequency of the spray granulation is preferably 36 to 48Hz, more preferably 38 to 45Hz, and still more preferably 40.5 to 41.5 Hz. In the invention, the air inlet temperature of the spray granulation is preferably 220-230 ℃, more preferably 222-228 ℃, and more preferably 225-226 ℃; the air outlet temperature of the spray granulation is preferably 85-100 ℃, more preferably 88-98 ℃, and more preferably 90-95 ℃. The present invention does not require any particular manner of spray granulation, and spray granulation known to those skilled in the art may be employed.

According to the invention, salt substances of zirconium and yttrium are not needed, a large amount of polluting ions such as acid radicals and ammonium radicals are prevented from being introduced into the raw materials, and even if the raw materials contain a small amount of acid radical ions and the roasting temperature is high, the acid radical ions in the raw materials can be completely burnt out, so that the defect of unstable powder performance caused by high acid radical ion content in the preparation process of the coprecipitation method is effectively overcome, and the batch and performance stability of the powder are improved. The invention can refine the powder to the nanometer level (below 100 nm) only by wet ball milling and wet sanding, has simple and convenient preparation process, low cost, short period and good repeatability, is more suitable for industrial production, solves the problems of high energy consumption and cost, large environmental pollution and the like in the coprecipitation method, and meets the development requirement of the preparation process of new materials in the future.

The invention also provides YSZ ceramic granulated powder for plasma spraying, which is prepared by the preparation method in the technical scheme and comprises the following components: 90-94 wt% of zirconium oxide and 6-10 wt% of yttrium oxide stabilizer; the grain size of the YSZ ceramic granulated powder is 30-150 mu m. In the invention, the YSZ ceramic granulated powder for plasma spraying is zirconia with yttria partially stabilized, and has a phase structure of mixed tetragonal phase and cubic phase, namely, a crystal lattice structure of zirconia with yttria dissolved in solid solution. In the invention, the particle size of the YSZ ceramic granulated powder for plasma spraying is 30-150 μm, preferably 50-130 μm, or preferably 80-150 μm; or preferably 60 to 130 μm. In the invention, the YSZ ceramic granulated powder sprayed by plasma comprises 90-94 wt% of zirconia, preferably 91.5-93.5 wt%, and more preferably 93 wt%; the YSZ ceramic granulated powder sprayed by the plasma comprises 6-10 wt% of yttrium oxide stabilizer, preferably 6.5-8.5 wt%, and more preferably 7 wt%.

The YSZ ceramic granulated powder for plasma spraying and the method for producing the same according to the present invention will be described in detail with reference to examples, but they should not be construed as limiting the scope of the present invention.

Example 1

The method comprises the steps of accurately weighing 940 parts of zirconia, 60 parts of yttria and 2 parts of dispersant poly-methyl-ammonium-methacrylate by taking the total mass of the zirconia and the yttria as 1000 parts, adding deionized water, adjusting the mass sum of the zirconia and the yttria in the mixed slurry to be 55% of the total mass of the zirconia, the yttria and the deionized water, and ball-milling the materials for 2 hours by using a stirring ball mill, wherein a grinding body is a zirconia ball with the particle size of 3-4 mm, and the ball-milling rotating speed is 160 r/min.

And (3) carrying out spray drying on the slurry after stirring and ball milling, and adjusting the atomization frequency to be 45Hz, the air inlet temperature to be 240 ℃ and the air outlet temperature to be 90 ℃ to obtain the yttrium oxide-zirconium oxide mixed raw material.

Accurately weighing 1000 parts of yttrium oxide-zirconium oxide mixed raw material and 20 parts of starch, uniformly stirring the yttrium oxide-zirconium oxide mixed raw material and the starch, and sintering at 1350 ℃ for 6 hours to obtain YSZ clinker. XRD analysis is carried out on the obtained YSZ clinker, and the YSZ clinker obtained by high-temperature calcination is known to synthesize a mixed phase structure of tetragonal phase and cubic phase, and no monoclinic phase appears, which indicates that the stabilizer yttrium oxide is dissolved in the zirconium oxide crystal lattice.

Accurately weighing 1000 parts of YSZ clinker and 2 parts of dispersant poly-methyl-ammonium-methacrylate respectively, and adding deionized water to obtain clinker slurry; and adjusting the YSZ clinker in the clinker slurry to 55 percent of the total mass of the YSZ clinker and deionized water, ball-milling the clinker slurry for 24 hours by using a ball mill, wherein a grinding body is zirconia balls with the particle size of 10-20 mm, and the ball-milling rotating speed is 40r/min to obtain the ball-milled slurry.

And (3) guiding the slurry subjected to ball milling into a sand mill, adjusting the YSZ clinker in the slurry to be 45% of the total mass of the YSZ clinker and deionized water, continuing sand milling for 6 hours, wherein a grinding body is zirconia beads with the particle size of 0.6-0.8 mm, and the sand milling rotating speed is 800r/min, so as to obtain sand milling slurry. And (3) performing field emission electron scanning microscope detection on the YSZ ceramic powder in the obtained sanding slurry, wherein the YSZ ceramic powder is refined to a nanometer level after sanding, and the particle size is uniform and less than 100 nanometers.

And (3) exporting the sand grinding slurry, adding a polyvinyl alcohol binder accounting for 1.5% of the total mass of the YSZ clinker, and performing spray granulation to obtain YSZ ceramic granulation powder for plasma spraying with the particle size of 60-150 mu m, wherein the sphericity and the fluidity are good, and the technological parameters of spray granulation equipment are that the atomization frequency is 36Hz, the air inlet temperature is 220 ℃ and the air outlet temperature is 85 ℃.

Preparing a thermal barrier coating by using the YSZ ceramic granulated powder for plasma spraying prepared in the embodiment 1 to obtain a thermal barrier coating a, a thermal barrier coating b, a thermal barrier coating c and a thermal barrier coating d; the cross-sectional topography is respectively shown in fig. 4, fig. 5, fig. 6 and fig. 7, and it can be seen from the figures that the melting degree of the powder under the action of the plasma current is relatively consistent, the particles formed by melting the nano powder are uniformly distributed and have similar size, large-size unmelted inclusions and cracks are not seen, the tissue is more uniform and compact, and the tissue structures of 4 thermal barrier coatings are consistent; and the life of 4 thermal barrier coatings was comparable. The YSZ ceramic granulated powder provided by the invention has stable performance, and the thermal barrier coating prepared in the same batch has uniform service life.

Example 2

The method comprises the steps of accurately weighing 930 parts of zirconia, 70 parts of yttria and 4 parts of dispersant ammonium polyacrylate by taking the total mass of the zirconia and the yttria as 1000 parts, adding deionized water, adjusting the mass sum of the zirconia and the yttria in the mixed slurry to be 58% of the total mass of the zirconia, the yttria and the deionized water, and ball-milling the materials for 3 hours by using a stirring ball mill, wherein a grinding body is a zirconia ball with the particle size of 4-5 mm, and the ball-milling rotating speed is 150 r/min.

And (3) directly drying the slurry subjected to stirring and ball milling for 12 hours at 90 ℃ by using an electric heating oven to obtain the yttrium oxide-zirconium oxide mixed raw material.

Accurately weighing 1000 parts of yttrium oxide-zirconium oxide mixed raw material and 30 parts of starch, uniformly stirring the yttrium oxide-zirconium oxide mixed raw material and the starch, and sintering the mixture at 1400 ℃ for 5 hours to obtain YSZ clinker. XRD analysis is carried out on the obtained YSZ clinker, and the YSZ clinker obtained by high-temperature calcination is known to synthesize a mixed phase structure of tetragonal phase and cubic phase, and no monoclinic phase appears, which indicates that the stabilizer yttrium oxide is dissolved in the zirconium oxide crystal lattice.

Accurately weighing 1000 parts of YSZ clinker and 4 parts of dispersant ammonium polyacrylate respectively, and adding deionized water to obtain clinker slurry; and adjusting the YSZ clinker in the clinker slurry to be 58% of the total mass of the YSZ clinker and deionized water, and ball-milling the clinker slurry for 21 hours by using a ball mill, wherein a grinding body is a zirconia ball with the particle size of 15-20 mm, and the ball-milling rotating speed is 50r/min to obtain the ball-milled slurry.

And (3) guiding the slurry subjected to ball milling into a sand mill, adjusting the YSZ clinker in the slurry to be 48% of the total mass of the YSZ clinker and deionized water, continuing sand milling for 5 hours, wherein a grinding body is zirconia beads with the particle size of 0.5-0.6 mm, and the sand milling rotating speed is 900r/min, so as to obtain sand milling slurry. And (3) performing field emission electron scanning microscope detection on the YSZ ceramic powder in the obtained sanding slurry, wherein the YSZ ceramic powder is refined to a nanometer level after sanding, and the particle size is uniform and less than 100 nanometers.

And (3) exporting the sand grinding slurry, adding a polyvinyl alcohol binder accounting for 1.2% of the total mass of the YSZ clinker, and performing spray granulation to obtain YSZ ceramic granulation powder for plasma spraying with the particle size of 50-130 mu m, wherein the sphericity and the fluidity are good, and the technological parameters of spray granulation equipment are that the atomization frequency is 39Hz, the air inlet temperature is 240 ℃ and the air outlet temperature is 90 ℃.

Preparing the thermal barrier coating from the prepared YSZ ceramic granulation powder for plasma spraying to obtain a thermal barrier coating a, a thermal barrier coating b, a thermal barrier coating c and a thermal barrier coating d; the structure of 4 thermal barrier coatings is consistent; and the life of 4 thermal barrier coatings was comparable. The YSZ ceramic granulated powder provided by the invention has stable performance, and the thermal barrier coating prepared in the same batch has uniform service life.

Example 3

The method comprises the steps of accurately weighing 920 parts of zirconia, 80 parts of yttria and 6 parts of dispersant sodium tripolyphosphate by taking the total mass of the zirconia and the yttria as 1000 parts, adding deionized water, adjusting the mass sum of the zirconia and the yttria in the mixed slurry to be 60% of the total mass of the zirconia, the yttria and the deionized water, and ball-milling the materials for 4 hours by using a stirring ball mill, wherein a grinding body is a zirconia ball with the particle size of 5-6 mm, and the ball-milling rotating speed is 140 r/min.

Drying the slurry after stirring and ball milling for 8h at 80 ℃ by an evaporator to obtain the yttrium oxide-zirconium oxide mixed raw material.

Accurately weighing 1000 parts of yttrium oxide-zirconium oxide mixed raw material and 40 parts of starch, uniformly stirring the yttrium oxide-zirconium oxide mixed raw material and the starch, and sintering at 1450 ℃ for 4 hours to obtain YSZ clinker. XRD analysis was performed on the obtained YSZ clinker, and the results are shown in fig. 1. As can be seen from fig. 1, the YSZ clinker obtained by high-temperature calcination has synthesized a mixed phase structure of tetragonal phase and cubic phase, and no monoclinic phase appears, indicating that the stabilizer yttria has been dissolved into the zirconia crystal lattice.

Accurately weighing 1000 parts of YSZ clinker and 6 parts of dispersant sodium tripolyphosphate respectively, and adding deionized water to obtain clinker slurry; adjusting the YSZ clinker in the clinker slurry to be 60% of the total mass of the YSZ clinker and deionized water, and ball-milling the clinker slurry for 18 hours by using a ball mill, wherein a grinding body is a zirconia ball with the particle size of 15-25 mm, and the ball-milling rotating speed is 60r/min to obtain the ball-milled slurry.

And (3) guiding the slurry subjected to ball milling into a sand mill, adjusting the YSZ clinker in the slurry to be 50% of the total mass of the YSZ clinker and deionized water, continuing sand milling for 4 hours, wherein a grinding body is zirconia beads with the particle size of 0.4-0.5 mm, and the sand milling rotating speed is 1000r/min to obtain sand milling slurry. And (3) performing field emission electron scanning microscope detection on the YSZ ceramic powder in the obtained sanding slurry, wherein the YSZ ceramic powder is refined to a nanometer level after sanding, and the particle size is uniform and less than 100 nanometers.

And (3) guiding the sand grinding slurry out, adding a polyvinyl alcohol binder accounting for 0.9% of the total mass of the YSZ clinker, and performing spray granulation to obtain YSZ ceramic granulation powder for plasma spraying with the particle size of 40-120 mu m, wherein the sphericity and the fluidity are good, and the technological parameters of spray granulation equipment are set to be that the atomization frequency is 42Hz, the air inlet temperature is 270 ℃ and the air outlet temperature is 95 ℃.

Example 4

The method comprises the steps of accurately weighing 910 parts of zirconia, 90 parts of yttria and 8 parts of sodium hexametaphosphate serving as a dispersing agent by taking the total mass of the zirconia and the yttria as 1000 parts, adding deionized water, adjusting the mass sum of the zirconia and the yttria in the mixed slurry to be 62% of the total mass of the zirconia, the yttria and the deionized water, and ball-milling the materials for 5 hours by using a stirring ball mill, wherein a grinding body is a zirconia ball with the particle size of 6-7 mm, and the ball-milling rotating speed is 130 r/min.

And centrifugally dewatering the slurry after stirring and ball milling, and drying for 5 hours at 90 ℃ by using an electric heating oven to obtain the yttrium oxide-zirconium oxide mixed raw material.

Accurately weighing 1000 parts of yttrium oxide-zirconium oxide mixed raw material and 50 parts of starch, uniformly stirring the yttrium oxide-zirconium oxide mixed raw material and the starch, and sintering at 1500 ℃ for 3 hours to obtain YSZ clinker. XRD analysis is carried out on the obtained YSZ clinker, and the YSZ clinker obtained by high-temperature calcination is known to synthesize a mixed phase structure of tetragonal phase and cubic phase, and no monoclinic phase appears, which indicates that the stabilizer yttrium oxide is dissolved in the zirconium oxide crystal lattice.

Accurately weighing 1000 parts of YSZ clinker and 8 parts of dispersant sodium hexametaphosphate respectively, and adding deionized water to obtain clinker slurry; and adjusting the YSZ clinker in the clinker slurry to be 62% of the total mass of the YSZ clinker and deionized water, ball-milling the clinker slurry for 15 hours by using a ball mill, wherein a grinding body is a zirconia ball with the particle size of 20-25 mm, and the ball-milling rotating speed is 70r/min to obtain the ball-milled slurry.

And (3) guiding the ball-milled slurry into a sand mill, adjusting the YSZ clinker in the slurry to be 52% of the total mass of the YSZ clinker and deionized water, continuing sand milling for 3 hours, wherein a grinding body is zirconia beads with the particle size of 0.3-0.4 mm, and the sand milling rotating speed is 1100r/min, so as to obtain sand milling slurry. The YSZ ceramic powder in the obtained sanding slurry was examined by a field emission electron scanning microscope, and the results are shown in fig. 2. As can be seen from FIG. 2, the YSZ ceramic powder after sanding has been thinned to nanometer level and has a uniform particle size of less than 100 nm.

And (3) leading out the sand grinding slurry, adding a polyvinyl alcohol binder accounting for 0.6% of the total mass of the YSZ clinker, and performing spray granulation to obtain the YSZ ceramic granulation powder for plasma spraying with the particle size of 30-100 microns, wherein the spray granulation equipment has the process parameters of 45Hz of atomization frequency, 300 ℃ of air inlet temperature and 95 ℃ of air outlet temperature. The result of optical microscopic analysis of the YSZ ceramic granulated powder obtained by the preparation is shown in fig. 3. As can be seen from FIG. 3, the nano-powder was spray-granulated to obtain a granulated powder having a uniform particle diameter of 30 to 100 μm and good sphericity and fluidity.

Example 5

The method comprises the steps of accurately weighing 900 parts of zirconia, 100 parts of yttria and 10 parts of dispersant polyethylene glycol by taking the total mass of the zirconia and the yttria as 1000 parts, adding deionized water, adjusting the mass sum of the zirconia and the yttria in the mixed slurry to be 65% of the total mass of the zirconia, the yttria and the deionized water, and ball-milling the materials for 6 hours by using a stirring ball mill, wherein a grinding body is a zirconia ball with the particle size of 7-8 mm, and the ball-milling rotating speed is 120 r/min.

And (3) performing filter pressing and dehydration on the slurry after stirring and ball milling, and drying for 5 hours at 90 ℃ by using an electric heating oven to obtain the yttrium oxide-zirconium oxide mixed raw material.

Accurately weighing 1000 parts of yttrium oxide and zirconium oxide mixed raw material and 60 parts of starch, uniformly stirring the yttrium oxide and zirconium oxide mixed raw material and the starch, and sintering the mixture for 2 hours at 1550 ℃ to obtain YSZ clinker. XRD analysis is carried out on the obtained YSZ clinker, and the YSZ clinker obtained by high-temperature calcination is known to synthesize a mixed phase structure of tetragonal phase and cubic phase, and no monoclinic phase appears, which indicates that the stabilizer yttrium oxide is dissolved in the zirconium oxide crystal lattice.

Accurately weighing 1000 parts of YSZ clinker and 10 parts of dispersant polyethylene glycol respectively, and adding deionized water to obtain clinker slurry; and adjusting the YSZ clinker in the clinker slurry to be 65% of the total mass of the YSZ clinker and deionized water, ball-milling the clinker slurry for 12 hours by using a ball mill, wherein a grinding body is a zirconia ball with the particle size of 20-30 mm, and the ball-milling rotating speed is 80r/min to obtain the ball-milled slurry.

And (3) guiding the slurry subjected to ball milling into a sand mill, adjusting the YSZ clinker in the slurry to be 55% of the total mass of the YSZ clinker and deionized water, continuing sand milling for 2h, wherein a grinding body is zirconia beads with the particle size of 0.1-0.2 mm, and the sand milling rotating speed is 1200r/min, so as to obtain sand milling slurry. And (3) performing field emission electron scanning microscope detection on the YSZ ceramic powder in the obtained sanding slurry, wherein the YSZ ceramic powder is refined to a nanometer level after sanding, and the particle size is uniform and less than 100 nanometers.

And (3) exporting the sand grinding slurry, adding a polyvinyl alcohol binder accounting for 0.3% of the total mass of the YSZ clinker, and performing spray granulation to obtain YSZ ceramic granulation powder for plasma spraying with the particle size of 30-80 microns, wherein the sphericity and the fluidity are good, and the technological parameters of spray granulation equipment are set to be that the atomization frequency is 48Hz, the air inlet temperature is 320 ℃ and the air outlet temperature is 100 ℃.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of YSZ ceramic granulation powder for plasma spraying comprises the following steps:

(5) mixing the sand grinding slurry obtained in the step (4) with a binder, and granulating to obtain YSZ ceramic granulation powder for plasma spraying;

the mass ratio of the zirconium oxide to the yttrium oxide in the mixed raw material is (915-935): (65-85).

2. The method of claim 1, wherein the method of preparing the mixed raw meal comprises: carrying out ball milling treatment and drying treatment on mixed slurry containing zirconium oxide, yttrium oxide, a dispersing agent and water in sequence to obtain mixed raw material containing yttrium oxide and zirconium oxide;

the ratio of the mass of the dispersant to the total mass of the zirconia and the yttria in the mixed slurry is 100: (0.20 to 1.0).

3. The preparation method of claim 1, wherein the high-temperature roasting time in the step (2) is 2-6 h.

4. The preparation method according to claim 1 or 3, wherein the mass ratio of the starch to the mixed raw meal in the step (2) is (2-6): 100.

5. the preparation method according to claim 1, wherein the dispersant in the step (3) is one or more of ammonium polyacrylate, sodium tripolyphosphate, sodium hexametaphosphate, ammonium polymethacrylate and polyethylene glycol;

the mass ratio of YSZ clinker to water in the step (3) is (55-65): (35-45).

6. The preparation method according to claim 1 or 5, wherein the rotation speed of the ball milling treatment in the step (3) is 40-80 r/min, and the time of the ball milling treatment is 12-24 h.

7. The preparation method according to claim 1, wherein the rotation speed of the sanding treatment in the step (4) is 800-1200 r/min, and the time of the sanding treatment is 2-6 h.

8. The method of claim 1, wherein the binder is used in step (5), and the mass ratio of YSZ clinker to binder is 100: (0.3 to 1.5).

9. The YSZ ceramic granulated powder for plasma spraying obtained by the preparation method according to any one of claims 1 to 8, comprising: 90-94 wt% of zirconium oxide and 6-10 wt% of yttrium oxide stabilizer; the grain size of the YSZ ceramic granulated powder is 30-150 mu m.