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Spinel-magnesium-based ceramic core and preparation method thereof

A ceramic core and spinel technology, which is applied in cores, casting molding equipment, casting molds, etc., can solve the problems that the casting temperature should not exceed 1650 ° C, the melting point of silicon-based ceramic cores is low, and the dimensional stability is affected. Achieve the effects of easy core removal, high compactness and reduced shrinkage

Active Publication Date: 2021-05-14
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, ceramic cores for precision casting include silicon-based, aluminum-based and magnesium-based, etc., and most of them are silicon-based, but the melting point of silicon-based ceramic cores is relatively low. The active elements react, and the phase change during preparation and use affects its dimensional stability
Although the aluminum-based ceramic core has a high service temperature, its core removal process is complicated (high pressure, strong acid or strong alkali conditions), pollutes the environment and corrodes alloy materials
Magnesium-based ceramic cores have the advantages of high bending strength and easy solubility in weak acids, but there are problems of high sintering shrinkage and poor thermal shock resistance
[0004] However, the existing disclosed ceramic cores doped with magnesia have metal oxide as the main crystal phase, adding magnesia whiskers to improve the compressive strength and impact strength of the product, and reduce the sintering temperature; Alumina is added to the magnesia ceramic core as a mineralizer to increase the operating temperature, or titanium dioxide is added as a mineralizer to promote the sintering of the core. However, the above technology does not solve the problem of high sintering shrinkage and thermal shock resistance. sex problem

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] A method for preparing a spinel-magnesium-based ceramic core, comprising the following steps:

[0053] (1) Mixing: By mass percentage, magnesia 40%, magnesia-aluminum spinel 55% and titanium dioxide 5% weigh the powder, add all the powder to the mixing tank, add agate beads and anhydrous Wet mixing with ethanol, the mass of ethanol added is 25% of the total powder mass, and the mixing time is 600min. After mixing, pour it into an enamel plate, evaporate it to dryness at 120°C with a heating plate, and pass through a 200-mesh stainless steel double-layer standard The sifted mixed powder is put into a ziplock bag for later use. Among them, the average particle size of magnesium oxide is 5.35 μm, the average particle size of magnesium aluminum spinel is 11.5 μm, and the average particle size of titanium dioxide is 6.73 μm.

[0054] (2) Binder preparation: put a clean beaker in an oil bath, put 93wt.% of paraffin wax and 5wt.% of beeswax into the beaker. Then, the temperatu...

Embodiment 2

[0061] A method for preparing a spinel-magnesium-based ceramic core, comprising the following steps:

[0062] (1) Mixing: By mass percentage, magnesia 35%, magnesia-aluminum spinel 62% and titanium dioxide 3% weigh the powder, add all the powder to the mixing tank, add agate beads and anhydrous Ethanol is used for wet mixing. The mass of ethanol added is 30% of the mass of the powder. The mixing time is 600 minutes. The mixed powder is packed in a ziplock bag for later use. Among them, the average particle size of magnesium oxide is 5.35 μm, the average particle size of magnesium aluminum spinel is 11.5 μm, and the average particle size of titanium dioxide is 6.73 μm.

[0063] (2) Binder preparation: put a clean beaker in an oil bath, put 92wt.% of paraffin wax and 5wt.% of beeswax into the beaker. Then, the temperature of the oil bath was raised to 90°C at 2.5°C / min, and stirred with a stirrer, and when the paraffin and beeswax were completely melted, the temperature was ra...

Embodiment 3

[0070] A method for preparing a spinel-magnesium-based ceramic core, comprising the following steps:

[0071] (1) Mixing: by mass percentage, magnesia 20%, magnesia-aluminum spinel 76% and titanium dioxide 4% weigh powder, all powders are added to the mixing tank, add agate beads and anhydrous Wet mixing with ethanol, the mass of ethanol added is 50% of the mass of the powder, and the mixing time is 660min. After mixing evenly, pour it into an enamel pan, evaporate it to dryness at 120°C with a heating plate, and pass it through a 200-mesh stainless steel double-layer standard sieve. The mixed powder is packed in a ziplock bag for later use. Among them, the average particle size of magnesium oxide is 5.35 μm, the average particle size of magnesium aluminum spinel is 11.5 μm, and the average particle size of titanium dioxide is 6.73 μm.

[0072] (2) Binder preparation: put a clean beaker in an oil bath, put 95wt.% of paraffin wax and 4wt.% of beeswax into the beaker. Then, th...

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Abstract

The invention discloses a spinel-magnesium-based ceramic core and a preparation method thereof, and belongs to the field of ceramic core preparation in the field of precision casting. Raw materials of the spinel-magnesium-based ceramic core comprise a powder raw material and a binder, and the powder raw material comprises the following components in percentage by mass: 50%-90% of spinel powder, 0%-30% of zirconium oxide powder, 0%-5% of titanium dioxide powder and the balance of magnesium oxide powder; and the mass of the binder accounts for 15-25% of the mass of the powder raw material. The preparation method of the spinel-magnesium-based ceramic core comprises the following steps: mixing powder according to the ratio, preparing a binder, mixing the preheated mixed powder and the binder to prepare slurry, carrying out compression molding on the slurry by adopting a hot-press injection molding method, and sintering to obtain the spinel-magnesium-based ceramic core. The spinel-magnesium-based ceramic core has the advantages of being high in strength, small in shrinkage rate and easy to remove, and meanwhile the thermal shock resistance is improved.

Description

technical field [0001] The invention belongs to the technical field of ceramic core preparation technology in the field of precision casting, and in particular relates to a spinel-magnesium-based ceramic core and a preparation method thereof. Background technique [0002] Today, ceramic cores are a key part of forming the complex cavities of near-net-shape investment investment castings. With the help of the ceramic core, a precision casting with a specific inner cavity shape can be obtained, and the dimensional accuracy of the wall thickness of the precision casting is guaranteed together with the shell. After the casting is completed, the ceramic core is removed from the casting by mechanical or chemical dissolution. Ceramic cores play an irreplaceable role in investment casting. [0003] At present, ceramic cores for precision casting include silicon-based, aluminum-based and magnesium-based, etc., and most of them are silicon-based, but the melting point of silicon-base...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/443C04B35/12B22C9/10C04B35/66
CPCC04B35/443C04B35/12B22C9/10C04B35/66C04B2235/3244C04B2235/3232C04B2235/3206C04B2235/96C04B2235/9615
Inventor 张力刘春阳陈晓郑文龙任士平
Owner NORTHEASTERN UNIV
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