Boron nitride composite paint for precise invested mold casting of titanium and titanium alloy

A technology of investment precision casting and composite coating, which is applied in casting molding equipment, coatings, molds, etc., and can solve problems such as sensitivity to pH changes and easy gelation.

Inactive Publication Date: 2007-04-11
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Zirconia, yttrium oxide, calcium oxide and other oxides that are less reactive with titanium liquid are mainly used in the surface layer and adjacent layer coatings of oxide ceramic shells. Among them, the surface layer coating with yttrium oxide as filler has better casting performance. However, yttrium oxide is prone to hydration, and its slurry is very sensitive to changes in pH value and is easy to gel
In addition, the oxide ceramic shell cannot avoid the formation of an α fouling layer on the surface of the casting, and the thickness of the α fouling layer ranges from 0.02 to 0.2 mm.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] Preparation of paint: 230 g of 325-mesh boron nitride was added to 300 g of binder yttrium sol. The boron nitride used was crushed and screened particles of high-purity boron nitride after hot pressing and sintering. And keep stirring with a stirrer, add 7.5g JFC type surfactant and 7.5g n-octanol, the viscosity of the prepared coating is about 15s. Use this coating as the titanium alloy surface coating to prepare the shell. Preparation of the mold shell: After the paint is prepared, dip the wax model into the prepared paint above. When the excess paint is almost flowing and the paint is evenly coated on the wax model, sand can be sprinkled, and 80 mesh boron nitride Sprinkle evenly on the painted wax pattern. After the coating is fully dried and hardened, repeat the above steps; then carry out the back coating, the binder in the back coating is silica sol, the filler in the back coating is 300 mesh mullite, and the refractory material used for sanding is 10-200 Molle...

Embodiment 2

[0014] Preparation of coating: 200 g of 325 mesh boron nitride and 250 g of yttrium oxide were added to 300 g of binder yttrium sol. Add 6g of aerosol OT type surfactant and 6g of active polysiloxane aqueous solution, and the viscosity of the prepared coating is about 25s. Preparation of the mold shell: After the paint is prepared, dip the wax model into the prepared paint above. When the excess paint is almost flowing and the paint is evenly coated on the wax model, sand can be sprinkled, and 80 mesh boron nitride Sprinkle evenly on the painted wax pattern. After the coating is fully dried and hardened, repeat the above steps; then carry out the back coating, the binder in the back coating is silica sol, the filler in the back coating is 300 mesh mullite, and the refractory material used for sanding is 10-200 Mollet. The back layer is coated and hung 5 times. Dewax the dried shells and put them in an autoclave for dewaxing. Put the dewaxed shell into a roasting furnace an...

Embodiment 3

[0016] Preparation of paint: Add 200g of boron nitride and 300g of zirconia of 325 mesh into 300g of zirconium diacetate binder, and stir continuously with a stirrer, add JFC surfactant and n-octanol, the viscosity of the prepared paint is about 25s. The boron nitride added to the paint is obtained by crushing and screening the mixture of high-purity boron nitride, boron oxide and aluminum nitride after hot pressing and sintering. Use this coating as the titanium alloy surface coating to prepare the shell. Use this coating as the titanium alloy surface coating to prepare the shell. Preparation of the mold shell: After the paint is prepared, dip the wax model into the prepared paint above. When the excess paint is almost flowing and the paint is evenly coated on the wax model, sand can be sprinkled, and 80 mesh boron nitride Sprinkle evenly on the painted wax pattern. After the coating is fully dried and hardened, repeat the above steps; then carry out the back coating, the b...

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Abstract

The present invention is composite boron nitride paint for precise invested mold casting of titanium and titanium alloy, and belongs to the field of non-ferrous metal casting technology. The composite paint consists of boron nitride 29-65 wt%, Yt sol or zirconium diacetate 33-70 wt%, surfactant 0.1-5 wt% and defoaming agent 0.1-5 wt%. The boron nitride is boron nitride 200 mesh below grains of pyrolytic boron nitride, crushed cold pressed boron nitride block, high purity boron nitride or boron nitride with small amount of flux. The composite boron nitride paint has the features of high floatability, easy maintenance and simple preparation process.

Description

technical field [0001] The invention relates to a boron nitride composite coating for titanium and titanium alloy investment precision casting, which belongs to the technical field of nonferrous metal investment precision casting. Background technique [0002] Titanium and titanium alloys are widely used in the aerospace industry, energy industry, marine transportation, chemical industry, etc. due to a series of excellent properties such as low density, high specific strength, and corrosion resistance. However, titanium and titanium alloys have high chemical activity at high temperatures, and they need to chemically react with various commonly used refractory materials. This requires very high chemical stability of refractory materials and binders used in titanium alloy casting. At present, the main method of casting titanium and titanium alloys is investment casting. Shells for titanium and titanium alloy precision casting can be roughly divided into: graphite shells, tun...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22C3/00
Inventor 沈彬刘宏葆蒋留全李重河程申涛周星朱明毛协民
Owner SHANGHAI UNIV
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