JP2002363731A - Member having scale deposition preventive film, and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide parts for high temperature and high pressure and a manufacturing method thereof which prevents any scales from being deposited on the surface of a member in high-temperature and high-pressure water for a long time, can be applied to parts requesting severe dimensional accuracy and parts of complicated shape, and can be obtained in an easy post-treatment at a relatively low cost. SOLUTION: A base material for the parts for high temperature and high pressure is installed at the predetermined position in a thermo-electronic type ion-plating apparatus, chromium is used for a target, the chromium is evaporated by the thermo-electronic type ion-plating apparatus, oxygen of the purity of >=99.0% is introduced at least during the film deposition so that the vacuum degree is in a range between 5×10<-5> and 1×10<-3> Torr., the evaporated chromium particles are reacted with oxygen to deposit a chromium oxide film having the film thickness of 2-20 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a scale which does not adhere to iron rust or corrosion products (hereinafter referred to as "scale") which grows on the surface of a member used in high-temperature and high-pressure water, or which is difficult to grow. The present invention relates to a member with a protective film and a method for manufacturing the same.

[0002]

2. Description of the Related Art High-temperature, high-pressure water is used as water used in a water supply system used in nuclear power generation and thermal power generation.
Many metal parts and devices are used to control pressure and flow rate in a water supply system.

[0003] Such members are exposed to high-temperature and high-pressure water for a long period of time, and as a result, scale is generated on the surface of such members. It is thought that this scale has iron and iron ions contained in high-temperature and high-pressure water attached thereto. If this adheres and grows, for example, in the case of a flow meter, the diameter becomes narrow, the flow velocity in that part becomes fast, and the flow rate apparently rises, resulting in erroneous recognition.
Further, in the case of a pump component, for example, a problem arises in that the pump pressure increases and a load is applied to the pump, thereby shortening the life of the pump.

[0004] In order to solve these problems, it has been considered to change the above-mentioned members from metal to ceramics. However, oxide ceramics such as alumina and silicon nitride not only dissolve in hot water, but also are subject to impact. However, there were no mechanical parts or large members that could be satisfactory in cost and reliability.

[0005] Also, attempts have been made to buff the surface of the member to reduce surface irregularities and eliminate the origin of scale adhesion. Although this method is somewhat effective, there is a problem that polishing cost is increased, and this method is not applicable to complicated shapes.

There is also a method of obtaining a member by performing various surface treatments such as wet chrome plating and painting on the surface of a substrate, but this method also has the following problems.
That is, hard chrome plating has high film hardness, abrasion,
Although excellent in corrosion resistance, the film stress is high and minute microcracks are generated on the surface. The scale adheres starting from the microcracks. When a member is obtained by forming a plating film on a substrate having a complicated shape, the thickness of the corners is increased by the edge effect, and the dimensional accuracy is deteriorated. In addition, the usual plating solution contains iron, which causes scale. In the case of painting, the paint is usually an organic substance and softens and dissolves in hot water.

As described above, at present, there is no effective countermeasure against scale adhesion, and only the surface of the member is polished or hard chrome plating is applied to only a part.

[0008]

The present invention can be applied to parts requiring strict dimensional accuracy and parts having complicated dimensions without scaling on the member surface in high-temperature and high-pressure water for a long time. An object of the present invention is to provide a component for high-temperature and high-pressure water which can be easily processed and obtained at a relatively low cost, and a method for producing the same.

[0009]

The high-temperature and high-pressure water component of the present invention which achieves the above object has a thickness of 2 to 20 μm on its surface.
A chromium oxide film, which is formed by evaporating chromium with a thermionic ion plating apparatus to remove oxygen having a purity of at least 99.0% at the time of film formation and a degree of vacuum of 5 × 10 − ^The film was formed while being introduced so as to be in the range of ⁵ to 1 × 10 ⁻³ Torr.

In another aspect of the present invention, a base material for a component for high-temperature and high-pressure water is installed at a predetermined position in a thermionic ion plating apparatus, chromium is used as a target, and chromium is used in a thermionic ion plating apparatus. At least at the time of film formation 99.0% or more oxygen,
The degree of vacuum is introduced to be in the range of ^{5 × 10- 5 ~1 × 10- 3} Torr, reacting the vaporized chromium particles and oxygen on a substrate, the range of the chromium oxide film having a thickness of 2~20μm A method for producing a component for high-temperature and high-pressure water, characterized by being formed by:

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The material of the base material for high-temperature and high-pressure water components in the present invention is not particularly limited. However, when applied to carbon steel or stainless steel used for flowmeters and pump parts where scale adheres and becomes problematic. Great effect.

The surface of the substrate is preferably smooth without any trace of machining. This is because, if there is a trace of machining, the stress of the coating film is concentrated at that location, and there is a possibility that the film is peeled off. In order to prevent this, for example, it is desirable to grind the surface to a roughness of 3 μm or less in Rmax, or to blast the surface of a member that is difficult to grind with glass beads of about # 400 to make the surface uniformly fine. Note that blasting is not suitable because parts having important corners may lack edges.

In high-temperature and high-pressure water, Fe ₃ O ₄ (macpenite), α-Fe
₃ O ₄ (Hematite), α-FeOOH (kacite) γ-FeOOH (retrocrocite)
Exists. Based on these, Fe ₃ O ₄
Precipitates. In the case of a SUS substrate and scale, both metal ions and oxygen ions are arranged in the same manner at the interface, so that the metal ions and the oxygen ions are electrically attracted to each other and the adhesive force is increased. On the other hand, since the chromium oxide film has a strong binding force between chromium and oxygen, even if magnetite approaches, it is difficult to bond with oxygen, so that the adhesion between the film and the scale becomes weak. In addition, the chromium oxide film has excellent corrosion resistance and is stable without being oxidized even in high-temperature and high-pressure water.
It is for this reason that the present invention obtains the member by applying a chromium oxide film on the surface of the substrate.

In order to obtain a chromium oxide film, a thermoelectron ion plating method is used. In this method, a coating material is placed in a water-cooled copper hearth, an electron beam generated from an electron gun is deflected by a magnetic field, and a diaphragm is formed. Or it can be shaken. The feature of this method is that the substrate surface can be cleaned by argon bombardment before the film is formed, and the kinetic energy is increased by ionization of the evaporated particles, thereby improving the adhesion and characteristics of the film.

In this method, the coating material is irradiated with an electron beam to be dissolved and evaporated. The evaporated particles, thermions, and the like pass through the plasma in which glow discharge occurs, and a part thereof is ionized. When an oxide film or the like is formed, oxygen is supplied as a reaction gas.

In the method of the present invention, since a film is formed on a substrate by evaporating a metal, a smooth film with little unevenness to which a melt from a target does not adhere can be formed. In the present invention, the thickness of the chromium oxide is 2 to 20 μm. If it is 2 μm or less, the abrasion resistance is low, and in the case of a complicated shape, there is a possibility that an unattached portion of the film exists. If it is 20 μm or more, the film stress is increased and the film may be peeled off.

[0017] a reaction gas in obtaining a film of the present invention oxygen by evacuating the vacuum chamber to 1 × 10- ⁵ Torr, the vacuum chamber oxygen in the range of ^{5 × 10- 5 ~1 × 10- 3} Torr Pour into Then, oxygen and chromium are reacted in the chamber to form a chromium oxide film on the base material. At this time, the reaction is not oxidized film is formed on the entire insufficient surface below ^{5 × 10- 5 Torr, 1 ×} 10- 3
If the pressure is equal to or higher than Torr, the degree of vacuum deteriorates and glow discharge may not be maintained. The vacuum chamber pressure is desirably set to about 5 × 10 ⁻³ Torr.

[0018]

Example 1 A SUS304 test plate having a size of 20 × 20 × 2 mm was immersed in ethanol, and the surface thereof was subjected to ultrasonic cleaning. Thereafter, it was dried and set in a vacuum chamber of a piercing type ion plating apparatus manufactured by Shinko Seiki. This apparatus has a 270-degree deflection electron gun manufactured by JEOL Ltd., and ionization is performed by generating plasma between an ionization electrode provided on the evaporation material and the evaporation material.

As the evaporation target, chromium metal of 99.9% purity obtained by a melting method was used. This chrome is copper
It was set in a molybdenum crucible.

The inside of the vacuum chamber was evacuated to 1 × 10 ⁻⁵ Torr, and the test plate was heated with a heater for 1 hour and maintained at a temperature of 300 ° C. Subsequently, argon gas was introduced into the vacuum chamber at a rate of 50 cc / min, a bias voltage of -800 V was applied, and ion bombardment was performed for 10 minutes. This treatment was performed to clean the substrate surface and increase the substrate temperature.

Next, an electron beam voltage of 10 kV and a current of 20 kV are used.
0mA, ionization current 50V, 5A, bias voltage-
The film was formed at 200 V for 30 minutes while flowing oxygen at a rate of 50 cc / min. The thickness of the formed chromium oxide film was 3 μm.

The temperature is 220 ° C., the pressure is 60 atm,
pH; 9.2, additives; magnetite 100 ppm,
Test liquid; hydrazine 0.5 ppm in pure water, test time;
A scale adhesion test was performed under the condition of 50 hours. Table 1 shows the obtained results. (Comparative Example) A titanium plate, a SUS plate with a Cr film formed thereon, and a SUS plate with Nb
Film formed, SUS plate formed with NbN film, SUS plate formed with Hf film, SUS plate formed with Hf
A scale adhesion test was performed in the same manner as in the example using an N film formed, a SUS plate formed with a Ta film, and a SUS plate plated with Cr. The obtained results are also shown in Table 1.

Table 1 Base material Scale adhesion SUS plate + CrO film Very small titanium plate Large SUS plate + Cr film Medium SUS plate + Nb film Large SUS plate + NbN film Large SUS plate + Hf film Large SUS plate + HfN film Film peeled SUS plate + Ta film Large SUS plate + Cr plating low As is apparent from Table 1, it was found that the chromium oxide coating film of the present invention had the smallest scale adhesion amount.

(Embodiment 2)
Size φ450mm Thickness 30mm, center φ240m
The orifice of the flow meter having the m holes was ultrasonically cleaned in a methylene chloride solution, dried, and subjected to the same treatment as in Example 1. The resulting film thickness was 3 μm. Surface roughness is Ra
= 0.04 μm and Rmax = 0.4 μm. As a result of a scale adhesion test of this part under an actual high-temperature and high-pressure environment, there was no scale adhesion even after a lapse of six months, and no change was observed in the flow rate. By the way, in the uncoated orifice, the scale adhered in three months and the flow rate changed.

[0025]

According to the present invention, the scale resistance of components used in high-temperature and high-pressure water can be improved. Further, according to the present invention, it is possible to provide a CrO film even on a component requiring particularly strict dimensional accuracy or a component having a complicated shape,
In addition, a CrO film can be obtained at relatively low cost without post-processing.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K029 AA02 BA43 BC01 BD03 CA04 DB03 DD04 EA01 EA03 EA05 FA04

Claims (2)

[Claims] A component used in high-temperature, high-pressure water,
A chromium oxide film having a thickness of 2 to 20 μm is formed on the surface of the chromium oxide film. The chromium oxide film evaporates chromium by a thermionic ion plating apparatus, and at least at the time of film formation, removes oxygen having a purity of 99.0% or more. , the degree of vacuum is ⁵ × 10- 5 ~1
A component for high-temperature and high-pressure water, wherein a film is formed while being introduced so as to be in a range of × 10 ⁻³ Torr. 2. A high temperature and high pressure water component base is placed at a predetermined position in a thermionic ion plating apparatus, chromium is used as a target, and chromium is evaporated by the thermionic ion plating apparatus. Purity 9 when membrane
Oxygen or 9.0%, the degree of vacuum ⁵ × 10- 5 ~1 × 10
For high-temperature, high-pressure water, characterized by forming a chromium oxide film with a thickness of 2 to 20 μm on a substrate by introducing chromium particles introduced in a range of ³ Torr and reacting the evaporated chromium particles with oxygen. The method of manufacturing the part.