JPH0255269A - Metallic capsule for hip treatment and hip treatment in oxygen atmosphere using same - Google Patents

Abstract

PURPOSE:To accomplish the densification treatment of porous sintered form and sintering of green compact in a capsule by making a HIP treatment in an oxygen atmosphere under specified conditions using silver (alloy) as an oxygen gas-selectively permeable capsule material. CONSTITUTION:A silver (alloy) capsule 1 is packed with an object to be treated 10 such as porous sintered form or green compact form suitable for treatment in an oxidative atmosphere. The resultant capsule 1 is then put to HIP treatment in an oxygen atmosphere at temperatures below the melting point of silver. Because of falling in the melting point of silver with increasing in oxygen partial pressure, said HIP treatment is made at <=770 deg.C, <=700 deg.C, <=620 deg.C or <=540 deg.C under an oxygen partial pressure of 100kgf/cm<2>, 200kgf/cm<2>, 300kgf/cm<2> or 400kgf/cm<2>, respectively.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a silver or silver alloy capsule used for processing oxide materials in an oxygen atmosphere HIP device (0□HIP);
and a treatment method using the same capsule.

[Conventional technology]

Since HIP equipment is used to sinter powder raw materials or densify porous materials, K is a membrane or plate metal material that does not permeate the pressure medium gas, or during processing (under heating). It is necessary to make a container called a capsule from a glassy material or the like which becomes molten, and to put the above-mentioned powder raw material or porous material into the container and perform HIP treatment.

This method (capsule HIP treatment) is applied to the sintering of high-speed steel powder materials, the sintering of silicon nitride (313N4) powder materials, and is also used in some industrial applications.

Figure 5 is a diagram illustrating the capsule (before H/P treatment) 25. After filling raw material powder into a cup 27 made of metal such as steel, the cup is fitted with a lid 4 made of the same material, and the end is sealed. Manufactured by welding.

FIG. 6 shows a capsule (after NIP treatment) 26 obtained by HIPing the above-mentioned capsule, and by applying heat and pressure at the same time, the raw material powder (material) is sintered and a sintered body 31 is obtained.

[Problem to be solved by the invention]

It is said that the problem with oxide-based superconducting materials (for example, Ba-Y-Cu-0-based) is to improve the critical temperature and critical current. To solve this problem, attempts have been made to improve the critical temperature by sintering in an oxidizing atmosphere or heat treatment, while to improve the critical current, low-density super Attempts have been made to densify and increase the density of conductive material sintered bodies by applying pressure by some means to increase the critical current.

In response to these attempts, HI using iron-based metal capsules
The application of P treatment was proposed, and tests were conducted in which the capsule was filled with oxygen gas and then pressurized and heated to sinter it into a dense material. However, in tests using iron-based materials for the capsule, the capsule material was is oxidized by oxygen gas filled with
There were problems such as breakage or sintering in an oxidizing atmosphere because the oxygen gas filled in the capsule was consumed due to oxidation of the capsule material.

[Means to solve the problem]

Commercially available pure silver with high oxygen solubility at high temperatures, or Ay-Cu, Ay-C:do, Ap-
Oxygen atmosphere HIP (02
Pressure sintering is performed in an atmosphere of high oxygen partial pressure.

[For production]

When processing materials loaded in a silver capsule using HIP processing in an oxygen atmosphere, a pressure difference occurs in the partial pressure of oxygen gas inside and outside the capsule (low pressure inside the capsule, high pressure outside the capsule), and the material dissolves into the silver capsule on the high pressure side outside. Oxygen gas evaporates inside under low pressure, so it behaves as if it were passing through the encapsulant.

〔Example〕

When a silver capsule was subjected to HIP treatment in an oxygen atmosphere, it was found that the silver capsule melted at a temperature below the melting point of silver, and the range of applicability of the silver capsule shown in Figure 1 was experimentally determined. Ta. In Figure 1, the horizontal axis plots the oxygen partial pressure (kgf/cm) during HIP treatment in an oxygen atmosphere, and the vertical axis plots the melting temperature of the silver capsule, which is approximately 960°C under atmospheric pressure. On the other hand, when the oxygen gas partial pressure is 100, 9f42'11' is about 770℃, 2
(XJkgf/cm, 2 Teha approx. 700℃, 300kg
f/z f about 620°G, 400kgf/cm
At about 540'C, it was confirmed that the melting point decreased as the oxygen gas partial pressure increased. Next, an oxide-based (Ba-Y-Cu/0-based) superconducting material powder was actually processed by HIP treatment in an oxygen atmosphere using a silver capsule.

The capsule I is shown in FIG. 2, and its cross section is shown in FIG.

Capsule 1 is made by making a circular indentation in a thin silver plate 2 (0.5fl plate thickness) using a punch and die, and after loading the compacted powder of the sample into this indentation, welding the four circumferences (seal welding part 3
) and produced it. At this stage, the green compact 10 is porous and has a low density. Further, there is a gap 4 between the powder compact 10 and the thin plate 2 of the capsule.

Figure 4 shows a treatment temperature of 550°G and an oxygen gas partial pressure of 200k.
A cross section of a capsule 5 subjected to HIP treatment in an oxygen atmosphere at a processing pressure of 2000 kgf/cm2 at 2° body is shown. Green compact 10
The density increased by heating and pressurization, resulting in a high-density sintered body, the gap 4 between the capsule and the compact 10 that existed before the treatment disappeared, and the capsule film 6 was fixed to the sintered body. It became a state. After removing the capsule film 6 by chemical treatment, the tt of the sintered silver was measured, and a weight increase of 3 to 5rn9 (sample type 1t700 to soo my) occurred, which was probably due to the addition of oxygen. It was confirmed that the treatment was carried out under an oxygen atmosphere. Similar effects were also confirmed for silver alloys such as Ay-Cu, At)-CaO, and Ay-W.

〔Effect of the invention〕

In a treatment method in which a porous sintered body or compacted powder body is loaded into a silver or scissor alloy capsule and subjected to oxygen atmosphere HIP treatment, the melting point of the capsule material at an oxygen partial pressure of 1 kgVm2, and 100 kgVm2. 770°G, 200 to 84
2 at 700″C1300C13O0 at 620°G,
By carrying out the treatment at a temperature not exceeding 400kli'f and 540℃ on table 2, it is possible to densify porous materials (density improvement) or sinter compacted powder bodies. .

[Brief explanation of the drawing]

Figure 1 is a diagram showing the applicable range of silver capsules in oxygen atmosphere HIP treatment, Figure 2 is a silver capsule (before treatment)
Figure 3 is a cross-sectional view of the silver capsule (before treatment);
Figure 4 is a cross-sectional view of a silver capsule after HIP treatment in an oxygen atmosphere, Figure 5 is a diagram explaining the structure of a conventional capsule (before treatment), and Figure 6 is a diagram explaining the structure of a conventional capsule (after treatment). It is a diagram. l...Silver or silver alloy capsule 10...Powder compact

Claims (2)

[Claims] (1) In a capsule used for densifying or sintering a porous sintered body or compacted body, which is preferably treated in an oxidizing atmosphere, by HIP treatment in an oxygen atmosphere, the material is silver or silver. H characterized by being an alloy
Metal capsule for IP processing. (2) In a treatment method in which a porous sintered body or a compacted powder body is loaded into a capsule made of silver or a silver alloy, and HIP treatment is performed in an oxygen atmosphere, the melting point of the capsule material is 100 kgf at an oxygen partial pressure of 1 kgf/cm^2. /cm^2 at 770℃, 20
700℃ at 0kgf/cm^2, 300kgf/cm^
An oxygen atmosphere HIP treatment method characterized in that the treatment is carried out at a treatment temperature not exceeding 620° C. at 2 and 540° C. at 400 kgf/cm^2.