阅读说明：本技术 一种氧化铪基陶瓷型芯及其制备方法 (Hafnium oxide based ceramic core and preparation method thereof ) 是由 梁康硕 刘枫 于 2019-11-11 设计创作，主要内容包括：一种氧化铪基陶瓷型芯及其制备方法,所属一种氧化铪基陶瓷型芯及其制备方法,氧化铪基陶瓷型芯,由氧化铪基陶瓷型芯粉料和增塑剂组成,氧化铪基陶瓷型芯粉料由稀土金属氧化物、氧化锆、氧化钇、氧化硅、氧化铪组成。氧化铪基陶瓷型芯的制备方法：1)制备氧化铪基陶瓷型芯粉料；2)制备氧化铪基陶瓷型芯料坯；3融化；4)压注；5)焙烧。本发明的氧化铪基陶瓷型芯及其制备方法,解决了含有高活性元素的合金精密铸造过程中,现有硅基及铝基陶瓷型芯高温性能低,以及在浇铸过程中引入杂质等问题,从而获得一种耐高温、纯度高的氧化铪基陶瓷型芯。(The hafnium oxide-based ceramic core consists of hafnium oxide-based ceramic core powder and a plasticizer, wherein the hafnium oxide-based ceramic core powder consists of rare earth metal oxide, zirconium oxide, yttrium oxide, silicon oxide and hafnium oxide. The preparation method of the hafnium oxide-based ceramic core comprises the following steps: 1) preparing hafnium oxide-based ceramic core powder; 2) preparing a hafnium oxide-based ceramic core blank; 3, melting; 4) pressure injection; 5) and (4) roasting. The hafnium oxide based ceramic core and the preparation method thereof solve the problems that the existing silicon-based and aluminum-based ceramic cores have low high-temperature performance, impurities are introduced in the casting process and the like in the precision casting process of the alloy containing high-activity elements, so that the hafnium oxide based ceramic core with high temperature resistance and high purity is obtained.)

1. The hafnium oxide-based ceramic core comprises, by mass, 100 parts (12-18) of hafnium oxide-based ceramic core powder and a plasticizer, wherein the hafnium oxide-based ceramic core powder comprises, by mass: 5-20% of rare earth metal oxide, 10-20% of zirconium oxide, 10-25% of yttrium oxide, 2-10% of silicon oxide and the balance of hafnium oxide.

2. The hafnium oxide-based ceramic core of claim 1, wherein the rare earth metal oxide is a mixture of two or more of neodymium oxide, dysprosium oxide, erbium oxide, ytterbium oxide, and cerium oxide.

3. The hafnium oxide based ceramic core of claim 1, wherein the plasticizer is a mixture of three or more of paraffin wax, liquid paraffin wax, butyl stearate, and PVB.

4. The hafnium oxide based ceramic core of claim 1, wherein the neodymium oxide, dysprosium oxide, erbium oxide, ytterbium oxide, cerium oxide have a particle size of 120 mesh or larger.

5. The hafnium oxide based ceramic core of claim 1, wherein the zirconia, silica, yttria have a particle size of 270 to 600 mesh.

6. The hafnium oxide based ceramic core of claim 1, wherein the hafnium oxide has a particle size of 150 to 800 mesh.

7. The method of making the hafnium oxide based ceramic core of claim 1, comprising the steps of:

step 1, preparing hafnium oxide-based ceramic core powder:

weighing raw material powder of rare earth metal oxide, zirconium oxide, yttrium oxide, silicon oxide and hafnium oxide according to the proportion, premixing the rare earth metal oxide powder for 3-5 h, premixing the zirconium oxide and yttrium oxide powder for 3-5 h, adding the mixed rare earth metal oxide powder into the hafnium oxide powder for mixing for 4-8 h, then adding the silicon oxide powder for mixing for 2-5 h, finally adding the premixed mixture of zirconium oxide and yttrium oxide, and dispersing and mixing by using a mixer for 3-8 h to form hafnium oxide-based ceramic core powder for later use;

step 2, preparing a hafnium oxide-based ceramic core blank:

weighing hafnium oxide-based ceramic core powder and a plasticizer according to the mass ratio of the hafnium oxide-based ceramic core powder to the plasticizer of 100 (12-18), firstly putting the plasticizer into an oil bath cylinder with a stirring function, heating to 80-90 ℃ for melting, then stirring for 3-6h at the stirring speed of 80-100 rpm, then adding the hafnium oxide-based ceramic core powder into the melted plasticizer three times, stirring for 8-20h at 85-125 ℃, taking out the slurry and dishing, and cooling to room temperature to form a hafnium oxide-based ceramic core blank for later use;

and step 3, melting:

placing the hafnium oxide-based ceramic core blank in an oil bath charging barrel, heating to 75-110 ℃, melting, and stirring at the stirring speed of 50-250 rpm;

step 4, pressure injection:

performing injection molding by using a ceramic core injection molding machine according to the required product size structure to form a hafnium oxide-based ceramic core blank;

and step 5, roasting:

embedding the hafnium oxide-based ceramic core blank into a high-temperature-resistant mixed filler, roasting at a final sintering temperature of 1500-1750 ℃, preserving heat for 3.5-7 h, and cooling to room temperature to obtain the hafnium oxide-based ceramic core.

8. The method of claim 7, wherein in step 5, the refractory hybrid filler is a mixture of zirconia powder and chopped zirconia ceramic fibers.

Technical Field

The invention belongs to the technical field of investment precision casting, and particularly relates to a hafnium oxide based ceramic core and a preparation method thereof.

Background

The development of aero-engines stems from the continuous breakthrough of new materials and new technologies. The improvement of the temperature bearing capability of the special metal turbine blade is urgent. In the prior art, for an active metal alloy casting process with high melting point and strong chemical activity, the existing silicon oxide and aluminum oxide can not be applied, and the hafnium oxide-based ceramic core has better high temperature resistance when the metal alloy is cast.

The invention provides a hafnium oxide-based ceramic core and a preparation method thereof, which can solve the problem of active metal alloy casting with high melting point and strong chemical activity, and the hafnium oxide can be dissolved in hydrofluoric acid and has good dissolution property in nitric acid, and simultaneously solves the related performances of the ceramic core in superalloy orientation and single crystal casting or eutectic alloy orientation casting.

Disclosure of Invention

Aiming at the problems that the high-temperature-resistant alloy of a hollow blade is more and more complex in the investment casting production technology in the prior precision casting, and a common material ceramic core cannot meet various physical and chemical properties in the alloy casting process, the scheme provides a hafnium oxide-based ceramic core and a preparation method thereof, aiming at solving the problems that the high-temperature properties of the prior silicon-based and aluminum-based ceramic cores are low, impurities are introduced in the casting process and the like in the alloy precision casting process containing high-activity elements, so that the hafnium oxide-based ceramic core with high temperature resistance and high purity is obtained, and the specific technical scheme is as follows:

the invention relates to a hafnium oxide-based ceramic core, which consists of hafnium oxide-based ceramic core powder and a plasticizer, wherein the mass ratio of the hafnium oxide-based ceramic core powder to the plasticizer is (12-18) of 100, the hafnium oxide-based ceramic core powder consists of rare earth metal oxide, zirconium oxide, yttrium oxide, silicon oxide and hafnium oxide, and the mass percentages are as follows: 5-20% of rare earth metal oxide, 10-20% of zirconium oxide, 10-25% of yttrium oxide, 2-10% of silicon oxide and the balance of hafnium oxide;

the rare earth metal oxide is a mixture of two or more of neodymium oxide, dysprosium oxide, erbium oxide, ytterbium oxide and cerium oxide;

the plasticizer is a mixture of more than three of paraffin, liquid paraffin, butyl stearate and PVB;

the particle size of the neodymium oxide, the dysprosium oxide, the erbium oxide, the ytterbium oxide and the cerium oxide is more than 120 meshes;

the particle size of the zirconium oxide, the silicon oxide and the yttrium oxide is 270-600 meshes;

the particle size of the hafnium oxide is 150-800 meshes;

the preparation method of the hafnium oxide based ceramic core comprises the following steps:

step 1, preparing hafnium oxide-based ceramic core powder:

weighing raw material powder of rare earth metal oxide, zirconium oxide, yttrium oxide, silicon oxide and hafnium oxide according to the proportion, premixing the rare earth metal oxide powder for 3-5 h, premixing the zirconium oxide and yttrium oxide powder for 3-5 h, adding the mixed rare earth metal oxide powder into the hafnium oxide powder for mixing for 4-8 h, then adding the silicon oxide powder for mixing for 2-5 h, finally adding the premixed mixture of zirconium oxide and yttrium oxide, and dispersing and mixing by using a mixer for 3-8 h to form hafnium oxide-based ceramic core powder for later use;

step 2, preparing a hafnium oxide-based ceramic core blank:

weighing hafnium oxide-based ceramic core powder and a plasticizer according to the mass ratio of the hafnium oxide-based ceramic core powder to the plasticizer of 100 (12-18), firstly putting the plasticizer into an oil bath cylinder with a stirring function, heating to 80-90 ℃ for melting, then stirring for 3-6h at the stirring speed of 80-100 rpm, then adding the hafnium oxide-based ceramic core powder into the melted plasticizer three times, stirring for 8-20h at 85-125 ℃, taking out the slurry and dishing, and cooling to room temperature to form a hafnium oxide-based ceramic core blank for later use;

and step 3, melting:

placing the hafnium oxide-based ceramic core blank in an oil bath charging barrel, heating to 75-110 ℃, melting, and stirring at the stirring speed of 50-250 rpm;

step 4, pressure injection:

performing injection molding by using a ceramic core injection molding machine according to the required product size structure to form a hafnium oxide-based ceramic core blank;

and step 5, roasting:

embedding the hafnium oxide-based ceramic core blank into a high-temperature-resistant mixed filler, roasting at a final sintering temperature of 1500-;

the preparation method of the hafnium oxide based ceramic core comprises the following steps:

in the step 5, the high-temperature resistant mixed filler is a mixture of zirconia powder and chopped zirconia ceramic fibers.

Compared with the prior art, the hafnium oxide based ceramic core and the preparation method thereof have the beneficial effects that:

firstly, for the casting of active metal alloy with high melting point and strong chemical activity, the existing silicon oxide and aluminum oxide can not be applied, and the hafnium oxide-based ceramic core has better high temperature resistance when the metal alloy is cast.

Secondly, the development of the hafnium oxide based ceramic core can solve the problem of active metal alloy casting with high melting point and strong chemical activity, and meanwhile, the hafnium oxide is soluble in hydrofluoric acid and has good dissolution in nitric acid. At the same time, HfO₂The melting point is as high as 2850 ℃, the temperature is far above 1600 ℃, the linear expansion coefficient is small, and the tracer can also be used as a tracer of a ceramic core material, so that the flaw detection of a precise metal piece is facilitated.

And thirdly, the hafnium oxide based ceramic core can solve the relevant performance of the ceramic core in the process of superalloy orientation and single crystal casting or oriented casting of eutectic alloy.

Fourthly, the process flow is simple, the hot-pressing injection molding mode is adopted, waste products generated in the injection molding process can be recycled, and waste of high-price raw materials is avoided.

Detailed Description

The present invention will be further described with reference to specific examples, but the present invention is not limited to these examples.