JPH0348265B2 - - Google Patents
Info
- Publication number
- JPH0348265B2 JPH0348265B2 JP59162093A JP16209384A JPH0348265B2 JP H0348265 B2 JPH0348265 B2 JP H0348265B2 JP 59162093 A JP59162093 A JP 59162093A JP 16209384 A JP16209384 A JP 16209384A JP H0348265 B2 JPH0348265 B2 JP H0348265B2
- Authority
- JP
- Japan
- Prior art keywords
- corrosion resistance
- sprayed
- corrosion
- heat treatment
- conditions
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000005260 corrosion Methods 0.000 claims description 49
- 230000007797 corrosion Effects 0.000 claims description 46
- 238000000034 method Methods 0.000 claims description 41
- 238000010438 heat treatment Methods 0.000 claims description 26
- 238000000576 coating method Methods 0.000 claims description 21
- 239000011248 coating agent Substances 0.000 claims description 20
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 16
- 238000005507 spraying Methods 0.000 claims description 12
- 239000007789 gas Substances 0.000 claims description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 10
- 239000001301 oxygen Substances 0.000 claims description 10
- 229910052760 oxygen Inorganic materials 0.000 claims description 10
- 239000007769 metal material Substances 0.000 claims description 3
- 238000007751 thermal spraying Methods 0.000 description 19
- 229910000851 Alloy steel Inorganic materials 0.000 description 17
- 239000011651 chromium Substances 0.000 description 13
- 229910052804 chromium Inorganic materials 0.000 description 12
- 239000000463 material Substances 0.000 description 12
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 10
- 239000007921 spray Substances 0.000 description 10
- 238000012360 testing method Methods 0.000 description 10
- 230000003647 oxidation Effects 0.000 description 9
- 238000007254 oxidation reaction Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 150000003839 salts Chemical class 0.000 description 7
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 230000001590 oxidative effect Effects 0.000 description 5
- 229910001220 stainless steel Inorganic materials 0.000 description 5
- 238000011282 treatment Methods 0.000 description 5
- 238000005536 corrosion prevention Methods 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- 238000007654 immersion Methods 0.000 description 4
- 230000010287 polarization Effects 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 239000010935 stainless steel Substances 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 3
- 238000002161 passivation Methods 0.000 description 3
- 238000007750 plasma spraying Methods 0.000 description 3
- 239000011780 sodium chloride Substances 0.000 description 3
- 230000000007 visual effect Effects 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
- C23C4/18—After-treatment
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Coating By Spraying Or Casting (AREA)
Description
【発明の詳細な説明】
産業上の利用分野
本発明は溶射と熱処理との組み合わせにより金
属材料の表面に緻密な被覆を形成させ、防食性を
付与するための方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for forming a dense coating on the surface of a metal material by a combination of thermal spraying and heat treatment to impart anti-corrosion properties.
従来の技術
溶射による防食方法には防食の機構からみて次
の二つの方法がある。一つはアルミニウムや亜鉛
等の卑な金属を溶射材として用い、その犠牲陽極
作用により電気化学的に素材を防食する方法であ
り、他の一つはクロム、ステンレス鋼等の高耐食
性金属、合金あるいはセラミツクスを溶射材とし
て用い、溶射皮膜の環境遮断の効果により素材を
防食する方法である。Prior Art There are two types of corrosion prevention methods using thermal spraying based on the mechanism of corrosion protection. One is to use base metals such as aluminum and zinc as a thermal spraying material, and the material is electrochemically protected against corrosion through its sacrificial anode action.The other is to use highly corrosion-resistant metals and alloys such as chromium and stainless steel. Another method is to use ceramics as a thermal spray material and use the environmental barrier effect of the thermal spray coating to prevent corrosion of the material.
水溶液環境における溶射による防食方法として
は、前者によるものが一般的であり、広く用いら
れている。しかし、この方法では、溶射皮膜を構
成する金属種が時間の経過に伴つて溶出したり、
溶射皮膜表面が腐食生成物によつて汚染され著し
く美観を損なうことがあり、また酸性溶液等の厳
しい腐食環境では、溶射皮膜を構成する金属種の
溶出が激しいため防食効果が短期間で失われる等
の欠点を有している。 The former method is common and widely used as a corrosion prevention method by thermal spraying in an aqueous solution environment. However, with this method, the metal species that make up the sprayed coating may elute over time, or
The surface of the sprayed coating may be contaminated by corrosion products, significantly impairing its appearance, and in severe corrosive environments such as acidic solutions, the metal species that make up the sprayed coating will be leached out rapidly, causing the anticorrosion effect to be lost in a short period of time. It has the following drawbacks.
後者による防食法では溶射皮膜が多孔質であつ
て素材の表面まで達する開孔がしばしば存在し、
その結果、環境遮断能力が劣るため、溶射後、二
次処理により環境遮断能力を高める必要がある。
また、溶射皮膜自体が、バルクの金属に比べて活
性化されているため、その腐食活性を低下させる
必要がある。このため、後者の方法では、溶射皮
膜に樹脂あるいはガラス等を含浸させて封孔処理
を行う方法（「各種腐食事例と最新防食設計・施
工技術総合資料集」経営開発センター出版部発行
（1979））あるいは、自溶合金溶射皮膜を再溶融さ
せる方法（（日本溶射協会誌18、p62（1981））等
が開発されている。これらの処理により溶射皮膜
の腐食活性は低下する。しかし、食塩水や硫酸等
の厳しい環境においては、溶射皮膜自体の耐食性
はステンレス鋼等に比べて低く、水溶液環境にお
ける防食方法として用いられるには至つていな
い。 In the latter corrosion prevention method, the sprayed coating is porous and there are often openings that reach the surface of the material.
As a result, the environmental shielding ability is poor, so it is necessary to improve the environmental shielding ability through secondary treatment after thermal spraying.
Furthermore, since the thermal spray coating itself is more activated than the bulk metal, it is necessary to reduce its corrosion activity. For this reason, in the latter method, the thermal spray coating is impregnated with resin or glass, etc. to seal the pores. ), or a method of remelting a self-fusing alloy sprayed coating ((Journal of the Japan Thermal Spraying Association 18, p. 62 (1981)) has been developed. These treatments reduce the corrosion activity of the sprayed coating. However, the corrosion activity of the sprayed coating is reduced. The corrosion resistance of the thermal spray coating itself is lower than that of stainless steel, etc. in harsh environments such as oxidation and sulfuric acid, and it has not yet been used as a corrosion prevention method in an aqueous environment.
発明が解決しようとする問題点
本発明者らは優れた耐食性を示す表面処理方法
を開発するために鋭意研究を重ねた結果、酸化時
の体積膨張が著しいクロムを溶射しその皮膜を酸
化性雰囲気で熱処理することによりその目的を達
成しうることを見出し、この知見に基づいて本発
明をなすに至つた。Problems to be Solved by the Invention As a result of extensive research in order to develop a surface treatment method that exhibits excellent corrosion resistance, the present inventors thermally sprayed chromium, which expands significantly during oxidation, and deposited the film in an oxidizing atmosphere. The inventors have discovered that the objective can be achieved by heat-treating the material, and based on this knowledge, the present invention has been accomplished.
問題点を解決するための手段
すなわち、本発明は、酸化時の体積膨張が著し
い金属の粉末を溶射した鉄鋼等の素材を高温の酸
素含有ガス中で熱処理し、その溶射皮膜を高温酸
化させて、素材に対する防食効果を高める方法を
提供するものである。Means for Solving the Problems That is, the present invention heat-treats a material such as steel sprayed with a metal powder whose volume expands significantly during oxidation in a high-temperature oxygen-containing gas, and oxidizes the sprayed coating at a high temperature. , provides a method for increasing the anti-corrosion effect on materials.
クロムの溶射皮膜は、酸素含有ガス中で高温で
熱処理することにより、溶射皮膜の表面及びその
内部で酸化を受け、体積膨張がおこり、溶射皮膜
の空孔率を減少させるため、溶射皮膜の防食性が
向上する。また、溶射皮膜は活性化されているた
め、それ自体の耐食性はバルクの金属に比べて低
いが、高温酸化することにより溶射皮膜が安定化
されるため、耐食性も向上する。 When thermally sprayed chromium coatings are heat-treated at high temperatures in an oxygen-containing gas, the surface and interior of the thermally sprayed coating undergoes oxidation, volumetric expansion occurs, and the porosity of the thermally sprayed coating decreases. Improves sex. Furthermore, since the sprayed coating is activated, its own corrosion resistance is lower than that of bulk metal, but the thermal sprayed coating is stabilized by high-temperature oxidation, so the corrosion resistance is improved.
したがつて、溶射材として、酸化の際体積膨張
が著しいクロム粉末を用い、それを溶射した後高
温酸化させることによつて、素材の耐食性は向上
するものと考えられる。 Therefore, it is thought that the corrosion resistance of the material can be improved by using chromium powder, which undergoes significant volumetric expansion during oxidation, as the thermal spraying material, and by oxidizing it at high temperature after thermal spraying.
耐食性の評価は0.5M硫酸溶液中及び0.5M食塩
水中における電位ステツプ法によるアノード分極
曲線の測定及び塩水噴霧試験によつて行つた。
0.5M硫酸溶液は耐全面腐食性の評価を行うため
に用いたが、アノード分極特性として活性態電位
域における極大電流密度及び不働態保持電流密度
が小さいものほど耐食性が良いと評価した。食塩
水は耐孔食性の評価を行うために用い、その評価
は孔食電位の貴卑によつて行つた。また、塩水噴
霧試験では、溶射皮膜に発錆が認められるに要す
る時間の長短によつて耐食性の評価を行つた。 Corrosion resistance was evaluated by measuring anode polarization curves using the potential step method in 0.5M sulfuric acid solution and 0.5M saline, and by salt spray testing.
A 0.5M sulfuric acid solution was used to evaluate general corrosion resistance, and it was evaluated that the anode polarization characteristics were such that the smaller the maximum current density in the active state potential region and the lower the passive state holding current density, the better the corrosion resistance. The saline solution was used to evaluate the pitting corrosion resistance, and the evaluation was performed based on the pitting potential. In addition, in the salt spray test, corrosion resistance was evaluated based on the length of time required for rust to appear on the sprayed coating.
溶射溶融粒子は溶射時には酸化を受けないこと
が好ましく、このため本発明における溶射法とし
ては不活性ガスをアークガス及び粉末供給ガスと
して用いるプラズマ溶射法が適しているが、アー
ク溶射法並びにレーザー溶射法によつても可能で
ある。また、熱処理は通常、酸化性雰囲気中で、
電熱炉や赤外線加熱炉等の炉を用いて行うが、ガ
スバーナーやプラズマトーチ等を用いても行うこ
とができる。 It is preferable that the sprayed molten particles do not undergo oxidation during thermal spraying, and therefore, a plasma spraying method using an inert gas as an arc gas and a powder supply gas is suitable as the thermal spraying method in the present invention, but arc spraying and laser spraying are also suitable. It is also possible by In addition, heat treatment is usually performed in an oxidizing atmosphere.
Although this is carried out using a furnace such as an electric heating furnace or an infrared heating furnace, it can also be carried out using a gas burner, a plasma torch, or the like.
本発明における酸化性雰囲気としては、酸素含
有率が１〜30％程度の酸素含有ガスを用いること
ができるが、通常は空気が使用される。熱処理温
度としては、600〜1300℃が用いられ、600℃未満
では十分な酸化を行うことができない。一般に酸
素含有率が低い場合には高温を必要とし、酸素含
有率が高い場合には低温で十分である。熱処理時
間は処理温度及び酸素含有率によつて異なるが、
５分から３時間の範囲である。溶射皮膜は50μｍ
以上にすることが望ましく、熱処理は酸化皮膜の
厚さが溶射皮膜の1/2以上となるように行うのが
望ましい。 As the oxidizing atmosphere in the present invention, an oxygen-containing gas having an oxygen content of about 1 to 30% can be used, but air is usually used. The heat treatment temperature used is 600 to 1300°C, and sufficient oxidation cannot be performed at less than 600°C. Generally, high temperatures are required when the oxygen content is low, and low temperatures are sufficient when the oxygen content is high. The heat treatment time varies depending on the treatment temperature and oxygen content, but
The duration ranges from 5 minutes to 3 hours. Thermal spray coating is 50μm
It is desirable that the heat treatment is performed so that the thickness of the oxide film is 1/2 or more of that of the thermally sprayed film.
本発明の方法においては、溶射と熱処理を別々
の工程で行つてもよいし、また一つの工程で行つ
てもよい。一つの工程で行う場合では、プラズマ
溶射を短距離で短時間行つた後、酸素含有ガスを
直ちに直接吹きつけることにより熱処理を行う。
この際、溶射皮膜は溶射時の加熱により1000℃以
上の高温の不活性ガス雰囲気中で形成され、それ
に続く酸化性のガス雰囲気中で、溶射時の余熱で
酸化される。 In the method of the present invention, thermal spraying and heat treatment may be performed in separate steps or in one step. When carried out in one step, after plasma spraying is carried out over a short distance for a short period of time, the heat treatment is carried out by directly blowing an oxygen-containing gas immediately after.
At this time, the thermal spray coating is formed in an inert gas atmosphere at a high temperature of 1000° C. or higher due to heating during thermal spraying, and is then oxidized in an oxidizing gas atmosphere by residual heat from thermal spraying.
発明の効果
本発明の方法によれば、耐食性に優れた緻密な
被覆を容易に形成することができ、しかも溶射と
熱処理とを一つの工程で行う実施態様に従えば、
熱処理炉を使用しなくても酸化処理が行える。こ
の場合には、任意の形状の素材に対して防食処理
を行うことができ、かつ作業効率にも優れている
ため、利用範囲は大幅に拡大され、工業的に極め
て望ましものといえる。Effects of the Invention According to the method of the present invention, a dense coating with excellent corrosion resistance can be easily formed, and according to an embodiment in which thermal spraying and heat treatment are performed in one step,
Oxidation treatment can be performed without using a heat treatment furnace. In this case, it is possible to perform anti-corrosion treatment on materials of any shape, and the work efficiency is also excellent, so the scope of use is greatly expanded and it can be said to be extremely desirable industrially.
実施例
次に実施例により本発明をさらに詳細に説明す
る。Examples Next, the present invention will be explained in more detail with reference to Examples.
例 １
低合金鋼にブラスト処理を行つた後、アルゴン
をアークガス及び粉末供給ガスとするプラズマ溶
射装置を用いて、粒子径が５〜44μｍの金属クロ
ム粉末を100μｍの厚さに溶射した。その後、熱
処理用赤外線加熱炉中に挿入し2.2％の酸素を含
む窒素気流中で1300℃で５分間の熱処理を行つ
た。耐食性の評価は電位ステツプ法により行つ
た。すなわち、脱酸素を行つた25℃の0.5M硫酸
溶液中において、５分毎に0.1Vずつ電位を増加
させながらアノード分極曲線を測定した。溶射後
熱処理した低合金鋼の不働態保持電流密度は、約
1μA／cm2と非常に小さく、鉄鋼またはクロムにみ
られるような活性態の存在は認められず、耐食性
が非常に優れているといえる。Example 1 After blasting low alloy steel, chromium metal powder having a particle size of 5 to 44 μm was sprayed to a thickness of 100 μm using a plasma spraying device using argon as arc gas and powder supply gas. Thereafter, it was inserted into an infrared heating furnace for heat treatment, and heat treatment was performed at 1300° C. for 5 minutes in a nitrogen stream containing 2.2% oxygen. Corrosion resistance was evaluated using the potential step method. That is, the anode polarization curve was measured in a deoxidized 0.5M sulfuric acid solution at 25°C while increasing the potential by 0.1V every 5 minutes. The passivation current density of post-spray heat treated low alloy steel is approximately
It is very small at 1 μA/cm 2 , and there is no active state found in steel or chromium, indicating that it has excellent corrosion resistance.
比較例 １
例１に示した低合金鋼を、溶射−熱処理を全く
行わないまま、例１と全く同一の手順・条件で耐
食性の評価を行つた。当試料では、活性態電位域
で0.2A／cm2、不働態電位域では、0.2ｍＡ／cm2の
電流密度を示した。これは、例１の溶射−熱処理
低合金鋼に比べて、活性態電位域で約５桁、不働
態電位域で約２桁大きな値であつた。このこと
は、溶射−熱処理を行わない低合金鋼は耐食性が
非常に低いことを示している。Comparative Example 1 The corrosion resistance of the low alloy steel shown in Example 1 was evaluated under exactly the same procedure and conditions as in Example 1, without any thermal spraying or heat treatment. This sample showed a current density of 0.2 A/cm 2 in the active potential range and 0.2 mA/cm 2 in the passive potential range. This value was about 5 orders of magnitude larger in the active potential range and about 2 orders of magnitude larger in the passive state potential range than the thermally sprayed and heat treated low alloy steel of Example 1. This shows that low alloy steel without thermal spraying and heat treatment has very low corrosion resistance.
次に、熱処理を行わない他は、例１と同一の手
順・条件でクロム溶射を行つた低合金鋼につい
て、例１と全く同一の手順・条件で耐食性の評価
を行つた。当試料では、−0.3V付近で0.01A／cm2
のピーク電流密度を有する活性態が認められ、−
0.3Vより貴な電位では電流密度は約１ｍＡ／cm2
であつた。耐食性評価試験後の溶射皮膜は剥離し
やすく、溶射皮膜の下地の低合金鋼に褐色の錆の
発生が目視観察により認められた。 Next, corrosion resistance was evaluated using the same procedure and conditions as in Example 1 for low-alloy steel that was subjected to chromium spraying under the same procedure and conditions as in Example 1, except that no heat treatment was performed. In this sample, 0.01A/cm 2 at around -0.3V
An active state with a peak current density of -
At potentials nobler than 0.3V, the current density is approximately 1mA/cm 2
It was hot. The thermal sprayed coating after the corrosion resistance evaluation test was easy to peel off, and brown rust was observed by visual observation on the low alloy steel underlying the thermal sprayed coating.
例 ２
例１と同一の手順・条件でクロムの溶射及び熱
処理を行つた低合金鋼に対して、脱酸素を行つた
25℃、0.5M食塩水中で電位ステツプ法により５
分毎に0.05〜0.1Vずつ電位を増加させて耐孔食性
試験を行つた。Example 2 Deoxidation was performed on low alloy steel that had been thermally sprayed with chromium and heat treated using the same procedure and conditions as Example 1.
5 by potential step method in 0.5M saline at 25℃.
A pitting corrosion resistance test was conducted by increasing the potential by 0.05 to 0.1 V every minute.
自然浸漬電位は約0.0Vであり、目視観察によ
れば孔食の発生は認められず、また1μA／cm2とい
う非常に低い不働態保持電流密度を示した。この
ことは当試料の耐食性が非常に高いことを示す。 The natural immersion potential was approximately 0.0V, no pitting corrosion was observed by visual observation, and the passivation current density was extremely low at 1 μA/cm 2 . This shows that the corrosion resistance of this sample is very high.
比較例 ２
例１に示した低合金鋼を溶射−熱処理を全く行
わないまま、例２と全く同一の手順・条件で耐食
性の評価を行つた。当試料の自然浸漬電位は約−
0.5Vであり、電位が増加するのに伴い電流密度
は急激に増加した。耐食性評価試験後の顕微鏡観
察により、試料表面に微小な食孔の発生が認めら
れた。このことは溶射−熱処理を行わない低合金
鋼の耐食性が非常に劣つていることを示す。Comparative Example 2 Corrosion resistance of the low alloy steel shown in Example 1 was evaluated under exactly the same procedure and conditions as in Example 2, without any thermal spraying or heat treatment. The natural immersion potential of this sample is approximately -
0.5V, and the current density increased rapidly as the potential increased. Microscopic observation after the corrosion resistance evaluation test revealed the occurrence of minute pits on the sample surface. This shows that the corrosion resistance of low alloy steel without thermal spraying and heat treatment is very poor.
次に、熱処理を行わない他は例２と同一の手
順・条件でクロム溶射を行つた試料について例１
と全く同一の手順・条件で耐食性の評価を行つ
た。当試料では自然浸漬電位は約−0.4Vを示し、
電位が増加するのに伴い急激な電流密度の増加が
認められた。 Next, Example 1 was applied to a sample that was chromium sprayed using the same procedure and conditions as Example 2, except that no heat treatment was performed.
Corrosion resistance was evaluated using exactly the same procedures and conditions. In this sample, the natural immersion potential was approximately −0.4V,
A rapid increase in current density was observed as the potential increased.
例 ３
例１と同一の手順・条件でクロム溶射及び熱処
理を行つた低合金鋼に対して、塩水噴霧試験によ
る耐食性の評価を行つた。塩水噴霧試験は、
JISZ2371に準じて行つた。すなわち、35℃の恒
温槽中に５％の食塩水を噴霧したが、その噴霧量
は80cm2当たり１〜２ml／hrであつた。Example 3 Low-alloy steel that had been subjected to chromium spraying and heat treatment under the same procedures and conditions as Example 1 was evaluated for corrosion resistance by a salt spray test. The salt spray test is
It was conducted in accordance with JISZ2371. That is, 5% saline was sprayed into a constant temperature bath at 35° C., and the spray amount was 1 to 2 ml/hr per 80 cm 2 .
1080時間の塩水噴霧試験後、目視観察をした結
果、当試料の表面には錆の発生は全く認められな
かつた。 After 1080 hours of salt spray test, visual observation revealed that no rust was observed on the surface of this sample.
比較例 ３
例１に示した低合金鋼を、溶射−熱処理を全く
行わないで、例３と全く同一の手順・条件で耐食
性の評価を行つた。30分間の塩水噴霧試験の結
果、斑点状の褐色の錆が、試料板のいたる所に発
生した。21時間後には、全面が褐食の錆で覆われ
た。Comparative Example 3 Corrosion resistance of the low alloy steel shown in Example 1 was evaluated under exactly the same procedure and conditions as in Example 3, without any thermal spraying or heat treatment. As a result of the 30-minute salt spray test, speckled brown rust appeared all over the sample plate. After 21 hours, the entire surface was covered in brown rust.
次に、熱処理を行わない他は、例１と同一の手
順・条件でクロム溶射を行つた試料について、例
３と同一の手順・条件で耐食性の評価を行つた。
４時間の塩水噴霧試験後には当試料表面に点状の
錆の発生が認められた。 Next, the corrosion resistance of the sample was evaluated using the same procedure and conditions as in Example 3 on a sample that had been thermally sprayed with chromium using the same procedure and conditions as in Example 1, except that no heat treatment was performed.
After the 4-hour salt spray test, spots of rust were observed on the surface of this sample.
例 ４
空気気流中900℃で５分間、熱処理を行つた他
は、例１と同一の手順・条件で溶射及び熱処理を
行つたクロム溶射−熱処理低合金鋼に対して、例
１と全く同一の手順・条件で耐食性の評価を行つ
た。Example 4 The same method as in Example 1 was applied to chromium sprayed-heat-treated low-alloy steel that was thermally sprayed and heat-treated under the same procedure and conditions as in Example 1, except that it was heat-treated at 900°C for 5 minutes in an air stream. Corrosion resistance was evaluated using different procedures and conditions.
当試料では、不働態保持電流密度は約10μA／
cm2と非常に小さく、アノード分極曲線には活性態
は認められなかつた。このことは、比較例１に示
した溶射及び熱処理を行わない低合金鋼と比較し
て当試料の耐食性が著しく高いことを示してい
る。 In this sample, the passivation current density is approximately 10μA/
cm 2 was very small, and no active state was observed in the anode polarization curve. This shows that the corrosion resistance of this sample is significantly higher than that of the low alloy steel shown in Comparative Example 1 which is not thermally sprayed or heat treated.
例 ５
空気気流中において、500及び600℃で３時間熱
処理を行つた他は例１と同一の手順・条件で溶射
及び熱処理を行つたクロム溶射−熱処理低合金鋼
に対して、例１と全く同一の手順・条件で耐食性
の評価を行い、熱処理温度の耐食性に及ぼす影響
を調べた。500及び600℃で３時間熱処理したクロ
ム溶射−熱処理低合金鋼の−0.2〜0.5Vの電位範
囲における電流密度は、それぞれ１ｍＡ／cm2、
30μA／cm2であつた。このため工業的に意味のあ
る熱処理温度は600℃以上であるといえる。Example 5 Chromium sprayed-heat treated low alloy steel was sprayed and heat treated under the same procedure and conditions as in Example 1, except that it was heat treated at 500 and 600℃ for 3 hours in an air stream. Corrosion resistance was evaluated using the same procedure and conditions, and the effect of heat treatment temperature on corrosion resistance was investigated. The current densities in the potential range of -0.2 to 0.5 V for chromium sprayed-heat treated low alloy steel heat treated at 500 and 600°C for 3 hours were 1 mA/cm 2 and 1 mA/cm 2 , respectively.
It was 30 μA/cm 2 . Therefore, it can be said that the industrially meaningful heat treatment temperature is 600°C or higher.
比較例 ４
厚さが異なる他は例１と同一の手順・条件でク
ロム溶射皮膜の厚さが40〜170μｍの異なつた７
種の試料を調製し、これについて例１と全く同一
の手順・条件で耐食性の評価を行つた。その結
果、0.6Vにおける電流密度は皮膜の厚さが増加
するに従つて一様に減少することがわかつた。ま
た、皮膜厚さが40、55、85及び170μｍの試料の
電流密度は、それぞれ70、10、１及び1μA／cm2で
あつた。電流密度が約10μA／cm2以下であれば耐
食性被覆として十分使用可能であるので工業的に
可能な溶射皮膜の厚さは55μｍ以上であることが
知られた。Comparative Example 4 The same procedure and conditions as Example 1 were used except for the difference in thickness, but the thickness of the chromium sprayed coating was 40 to 170 μm.
Seed samples were prepared, and their corrosion resistance was evaluated using the same procedure and conditions as in Example 1. As a result, it was found that the current density at 0.6V uniformly decreased as the film thickness increased. The current densities of samples with film thicknesses of 40, 55, 85, and 170 μm were 70, 10, 1, and 1 μA/cm 2 , respectively. It is known that if the current density is about 10 μA/cm 2 or less, it can be sufficiently used as a corrosion-resistant coating, so the thickness of an industrially possible thermal spray coating is 55 μm or more.
参考例
通常使用されている耐食性材料であるSUS304
ステンレス鋼に対して例１と全く同一の手順・条
件で硫酸溶液中における耐食性の評価を行つた。
当試料では、−0.1V付近に0.1ｍＡ／cm2のピーク電
流密度を有する活性態が認められ、0.2Vより貴
な電位では、不働態保持電流密度は約1μA／cm2で
あつた。次に、食塩水溶液中における耐食性評価
を例２と全く同一の手順・条件で行つた。当試料
の自然浸漬電位は約0.0Vであつたが0.6V付近に
食孔発生に伴う電流密度の急激な増加が認められ
た。このことは、例１に記した溶射−熱処理低合
金鋼がSUS304ステンレス鋼より耐食性が優れて
いることを示す。Reference example: SUS304, a commonly used corrosion-resistant material
Corrosion resistance of stainless steel in a sulfuric acid solution was evaluated using the same procedure and conditions as in Example 1.
In this sample, an active state with a peak current density of 0.1 mA/cm 2 was observed near -0.1V, and at a potential more noble than 0.2V, the current density maintaining the passive state was about 1 μA/cm 2 . Next, corrosion resistance evaluation in a saline solution was carried out using exactly the same procedure and conditions as in Example 2. The natural immersion potential of this sample was approximately 0.0V, but a rapid increase in current density was observed around 0.6V due to the formation of pitting. This shows that the thermal sprayed and heat treated low alloy steel described in Example 1 has better corrosion resistance than SUS304 stainless steel.
Claims (1)
酸素含有ガス中で熱処理を行うことを特徴とする
金属材料の耐食性被覆方法。1 After spraying chromium powder on the surface of the metal material,
A method for coating metal materials with corrosion resistance, the method comprising performing heat treatment in an oxygen-containing gas.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16209384A JPS6141758A (en) | 1984-07-31 | 1984-07-31 | Covering method of metallic material by spraying and heat treatment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16209384A JPS6141758A (en) | 1984-07-31 | 1984-07-31 | Covering method of metallic material by spraying and heat treatment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6141758A JPS6141758A (en) | 1986-02-28 |
| JPH0348265B2 true JPH0348265B2 (en) | 1991-07-23 |
Family
ID=15747937
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16209384A Granted JPS6141758A (en) | 1984-07-31 | 1984-07-31 | Covering method of metallic material by spraying and heat treatment |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6141758A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09144689A (en) * | 1995-09-20 | 1997-06-03 | Hitachi Ltd | Pump and manufacture thereof |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19681296C2 (en) * | 1995-03-08 | 2003-01-23 | Tocalo Co Ltd | Composite coating element and method of making the same |
| KR101393327B1 (en) * | 2012-05-10 | 2014-05-09 | 한국수력원자력 주식회사 | Plasma spray surface coating on Zirconium alloy for increasing the corrosion resistance at very high temperature |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4510081Y1 (en) * | 1966-08-24 | 1970-05-11 | ||
| JPS5198637A (en) * | 1975-02-26 | 1976-08-31 | ||
| JPS57114680A (en) * | 1980-08-16 | 1982-07-16 | Kernforschungsanlage Juelich | Porous oxide diaphragm for alkali electrolysis and production and use thereof |
-
1984
- 1984-07-31 JP JP16209384A patent/JPS6141758A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4510081Y1 (en) * | 1966-08-24 | 1970-05-11 | ||
| JPS5198637A (en) * | 1975-02-26 | 1976-08-31 | ||
| JPS57114680A (en) * | 1980-08-16 | 1982-07-16 | Kernforschungsanlage Juelich | Porous oxide diaphragm for alkali electrolysis and production and use thereof |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09144689A (en) * | 1995-09-20 | 1997-06-03 | Hitachi Ltd | Pump and manufacture thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6141758A (en) | 1986-02-28 |
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