Presintering process for reducing inequality in density of sintered material

一种烧结材料、均匀性的技术,应用在降低烧结材料密度不均匀性的工艺领域,能够解决微结构挥发/浓缩晶粒粗化等问题

Inactive Publication Date: 2008-01-30
GENERAL ELECTRIC CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This in turn leads to volatilization / condensation grain coarsening of the microstructure

Method used

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Examples

Experimental program
Comparison scheme
Effect test

experiment example 1

[0039] The expansion rod is uniaxially pressed to 43MPa in a hardened steel mold, and then cold isostatically pressed to 275MPa in a rubber bag. The green density of the rod obtained from the geometric measurement is 54% of the theoretical value, and the size of the rod after the expansion test is about 5.2mm×5.8mm×14.6mm. The dilatometer is operated under vacuum, rising to 1600°C at a rate of 5°C / min, and the temperature is not constant during this process. The first sample (sample 1) was determined to be magnesium aluminum oxide (MgAl) containing 9 ppm chlorine (weight) and 2 o 4 ) powder preparation. A second sample (Sample 2) was prepared from the same starting powder, but with the addition of 18 ppm by weight of lithium in the form of lithium hydroxide (equivalent to the stoichiometric LiCl compound used to generate the stoichiometric LiCl compound in the presence of 9 ppm chlorine 10 times the amount of lithium required). In sample 1, no lithium source was added, at 1...

experiment example 2

[0041] A magnesium aluminum oxide (MgAl) containing 260ppm chlorine and 2 o 4 ) powder (Sample 3) was uniaxially pressed to 100 MPa, followed by cold isostatic pressing to 275 MPa. The dimensions of the sample thus pressed were 12.3 mm in diameter and 1.6 mm in thickness. The geometrically measured green density was 52%. A second sample of the same powder (sample 4) was treated in the same manner except that lithium nitrate was added, and the moles of lithium left after the decomposition of the nitrate were 1.68 times the moles of chlorine contained. Sintered to 1283°C / 3h in flowing oxygen, the density of sample 3 was 96.2% of the theoretical density, and the density of sample 4 was 98.2% of the theoretical density.

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PUM

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Abstract

The present invention discloses a presinter technology for reducing the ununiformity of sintering material density, including: (a) providing a mixture, which comprises (i) a first sintered material with impurity, which generates higher vapor tension than the pure material due the impurity during the sintering process; and (ii) a second material, which has better affinity to the impurity than the first sintering material; (b) heating the mixture with adequate time at certain temperature, to make the second material weaken partly the trend that the first sintering material increases the vapor tension during the sintering process. Other implementing solutions are also disclosed in the present invention.

Description

[0001] U.S. Government Statement of Interest [0002] Portions of the invention described or claimed herein were made with United States Government support under Government Contract No. W56HZV-05-C-0517 awarded by the United States Military Research Laboratory. The government has certain rights in this invention. technical field [0003] The present invention relates to a process for reducing the density inhomogeneity of sintered materials. Background technique [0004] During the sintering process of metal oxide and non-oxide materials and ceramic materials, impurities such as halogens, especially chlorine and fluorine, will be mixed in the form of gas, while oxygen impurities will be mixed into non-oxide metal and ceramic materials. The gas thus mixed will react with the metal or ceramic material to form one or more secondary gaseous products containing one or more constituent elements of the metal or ceramic material, thereby significantly increasing the vapor pressure o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/64C04B35/63C04B35/01
CPCC04B2235/724C04B2235/608C04B2235/6587B22F2999/00C04B2235/3203C04B2235/661B22F3/1003C04B35/443B22F2201/40
Inventor S·M·斯维尼T·约斯尼克
Owner GENERAL ELECTRIC CO
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