JPS58106743A - Target for x-ray tube - Google Patents

Abstract

PURPOSE:To easily form a blackened layer having the uniform thickness and adhesion property thereof by forming the first electrodeposited layer on the second region except the first region irradiated by electron rays, and forming the second electrodeposited layer comprising blackened Cr on said first electrodeposited layer. CONSTITUTION:A Cr layer having the thickness of, e.g., 1-3mum is formed by subjecting a graphite substrate serving as a target substrate to electrolytic polishing, masking the electron ray irradiation orbital portion of said substrate, and subjecting a region except said orbital portion to Cr plating. A 1-2mum thick blackened Cr plated layer is formed by subjecting said Cr plated layer to a degassing treatment after forming said Cr plated layer, and then subjecting said Cr plated layer to blackened Cr plating so as to cover said Cr plated layer. Hereby, it is possible to easily form a blackened material layer having the good adhesion property using an aqueous solution and uniform thickness thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an X-ray tube target for generating X-rays by irradiation with electron beams.

Conventionally, this type of X-ray tube has a type that covers the area other than the area irradiated with X-rays with a black material layer to increase the thermal emissivity of the target used in a vacuum atmosphere. There is something. The black material layer mentioned above is usually
It is formed of a mixture containing titanium dioxide and at least one other type of refractory oxide additive.

However, the mixtures forming these black material layers cannot achieve sufficient adhesion to the target substrate unless they are heat-treated at a high temperature of about 1500 to 1600°C.

Furthermore, spraying using a plasma gun or the like has the disadvantage that it is difficult to obtain a black material layer with a uniform thickness. Furthermore, none of these targets having a black material layer has any measures against peeling of the black material layer.

It is an object of the present invention to provide a target for an X-ray tube with a layer of black material that can be deposited at low temperatures and has a uniform thickness showing sufficient adhesion.

Another object of the present invention is to provide an X-ray tube target that can prevent the black material layer from peeling off.

Another object of the present invention is to provide an x-ray tube target with a layer of black material that does not contain titanium dioxide.

According to the present invention, an X-ray tube target has a first region including a portion irradiated with an electron beam and a second region excluding the first region.

An X-ray tube target is obtained having a first electrodeposited layer formed on the second region and a second electrodeposited layer made of blackened chromium formed on the first electrodeposited layer.

An embodiment of the present invention will be described below.

Example 1 First, a graphite substrate was prepared as a target substrate, and this graphite substrate was electrolytically polished. After electrolytic polishing, the electron beam irradiation trajectory portion of the substrate was masked, and the area other than the masked trajectory portion was plated with chrome to form a chromium plating layer having a thickness of 1 to 3 microns. Chrome plating was performed using a chromic acid electrolyte. After forming the chromium plating layer, a degassing treatment was performed, and then blackened chromium plating was applied to cover the chromium plating layer to form a blackened chromium plating layer of 1 to 2 microns. The electrolyte used for this blackened chromium plating was chromic acid 300.17. , l-IJium fluoride 7F, thorium nitrate 10 g, and barium carbonate 0.6 g dissolved in water lt were used. During this plating, the anode material is
Using a 5% Pb-Sn alloy, the solution temperature was 20°C.
A current of 0 amperes/dm3 was applied for 5 minutes. The degree of blackness of the blackened chromium plating layer thus obtained is as per the Japanese Paint Industry Standard color sample J11035. It corresponded to J11037.

After forming the blackened chromium layer, the mask was peeled off, and a rhenium-tungsten alloy layer was deposited on the electron i irradiation trajectory by a conventional method to produce a coupe for an X-ray tube.

Although the target thus obtained was deposited at a low temperature, no peeling of the blackened chromium layer was observed even after repeated thermal cycle heating in a vacuum in the temperature range of 700 to 1300°C. And.

Its blackness was also not impaired. The thermal emissivity and absorption rate of the blackened chromium layer were 0.18 and 0.97, respectively. In this way, the chromium layer, which has good adhesion to graphite and blackened chromium, is deposited as a base between the blackened chromium layer and the graphite substrate. By plating, we were able to form a black material layer that could withstand high temperatures.

Example 2 In this Example 2, a transparent glass layer is further applied on the blackened chromium layer obtained in Example 1 to prevent a change in the color tone of the blackened chromium layer. Specifically, first, the target obtained in Example 1.

By weight, StO□75 cm At2057 '16 #
B2O59chi.

A rapidly cooled glass containing N≦2066% and 3% BaO (hereinafter simply referred to as frit) was prepared. next.

This frit was crushed to 325 mesh, water and bentonite were added to the crushed frit, and zAl2
At least one ° oxide selected from O5m Mgo z and Z r O2 based on the weight of the frit.

5 to 8 times the amount was added to form a slurry. in this way.

Adding the above-mentioned oxides to the frit.

This is to raise the firing temperature and to give the fired product a transparent feel.

Next, a slip-like mixture of frit and oxide is applied by spraying, dipping, or brush painting.

It is applied onto the blackened chromium layer and dried at a temperature of 120°C. Next is 1. Using an electric furnace, l Q +mHg
This was baked at a temperature of 1500° C. for 15 minutes in a vacuum atmosphere of about 100 mL to form a glass coating of 10 microns.

As a result, the blackened chromium layer has high transparency and 15
At temperatures of about 0.001::, a glass coating was formed that did not soften. Since this glass coating has good adhesion to the blackened chromium layer, there is no fear that the glass coating itself will peel off from the blackened chromium layer. Also.

Since the glass coating has high transparency, it does not have any adverse effect on reducing the thermal emissivity and can prevent the blackened chromium layer from fading.

According to the present invention as described above, a blackening material layer with good adhesion can be easily formed using an aqueous solution. It was also confirmed that the blackening material layer obtained by the present invention is superior in uniformity to that obtained by the conventional method.

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Claims (1)

[Claims] 1. In an X-ray tube target having a first region including a portion irradiated with an electron beam and a second region excluding the first region, A tag for an X-ray tube characterized by having a first electrodeposited layer formed on the electrodeposited layer and a second electrodeposited layer made of blackened chromium formed on the first electrodeposited layer. In an X-ray tube target having a first region including a portion irradiated with an electron beam and a second region excluding the first region, a first region formed on the second region
and a second electrodeposited layer of blackened chromium formed on the first electrodeposit layer. 4. A target for an X# tube, comprising a transparent glass layer deposited on the second electrodeposition layer.