JPH04180592A - Zn-mg alloy plated steel sheet excellent in plating adhesion and corrosion resistance and its production - Google Patents
Zn-mg alloy plated steel sheet excellent in plating adhesion and corrosion resistance and its productionInfo
- Publication number
- JPH04180592A JPH04180592A JP30710090A JP30710090A JPH04180592A JP H04180592 A JPH04180592 A JP H04180592A JP 30710090 A JP30710090 A JP 30710090A JP 30710090 A JP30710090 A JP 30710090A JP H04180592 A JPH04180592 A JP H04180592A
- Authority
- JP
- Japan
- Prior art keywords
- plating
- steel sheet
- corrosion resistance
- layer
- alloy
- 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.)
- Pending
Links
- 238000007747 plating Methods 0.000 title claims abstract description 90
- 230000007797 corrosion Effects 0.000 title claims abstract description 50
- 238000005260 corrosion Methods 0.000 title claims abstract description 50
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 47
- 239000010959 steel Substances 0.000 title claims abstract description 47
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 229910000861 Mg alloy Inorganic materials 0.000 title claims description 5
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 32
- 239000000956 alloy Substances 0.000 claims abstract description 32
- 229910009369 Zn Mg Inorganic materials 0.000 claims abstract description 21
- 229910007573 Zn-Mg Inorganic materials 0.000 claims abstract description 21
- 238000009713 electroplating Methods 0.000 claims abstract description 12
- 239000011248 coating agent Substances 0.000 claims abstract description 11
- 238000000576 coating method Methods 0.000 claims abstract description 11
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 claims abstract description 6
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical compound [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 claims description 13
- 150000003839 salts Chemical class 0.000 claims description 11
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 10
- 238000011282 treatment Methods 0.000 claims description 8
- 230000007423 decrease Effects 0.000 claims description 5
- 150000001805 chlorine compounds Chemical class 0.000 claims description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 3
- 229910052804 chromium Inorganic materials 0.000 claims description 3
- 239000011651 chromium Substances 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 2
- 239000004593 Epoxy Substances 0.000 abstract description 2
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 abstract description 2
- 239000011347 resin Substances 0.000 abstract description 2
- 229920005989 resin Polymers 0.000 abstract description 2
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 abstract 2
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 abstract 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 abstract 2
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 abstract 2
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 229910001629 magnesium chloride Inorganic materials 0.000 abstract 1
- 239000001103 potassium chloride Substances 0.000 abstract 1
- 239000000377 silicon dioxide Substances 0.000 abstract 1
- 239000011780 sodium chloride Substances 0.000 abstract 1
- 239000011592 zinc chloride Substances 0.000 abstract 1
- 235000005074 zinc chloride Nutrition 0.000 abstract 1
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 26
- 238000000034 method Methods 0.000 description 14
- 230000000694 effects Effects 0.000 description 6
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 6
- 238000011156 evaluation Methods 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 239000004566 building material Substances 0.000 description 2
- 230000002542 deteriorative effect Effects 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- 229910001335 Galvanized steel Inorganic materials 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 229910009367 Zn M Inorganic materials 0.000 description 1
- 229910001297 Zn alloy Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 239000010960 cold rolled steel Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000006258 conductive agent Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000008397 galvanized steel Substances 0.000 description 1
- 238000007602 hot air drying Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】
〈産業上の利用分野〉
本発明は、自動車、家電、建材等に用いられる耐食性に
優れたＺｎ−一合金めっき鋼板およびその製造方法に関
するものである。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a Zn-mono alloy plated steel sheet with excellent corrosion resistance used in automobiles, home appliances, building materials, etc., and a method for manufacturing the same.
〈従来の技術〉
鋼板は自動車、家電、建材等に広く用いられているが、
通常の試用環境下では錆びてしまう、このため、近年で
は錆びを防ぐためのめっき処理された鋼板が広く用いら
れている。めっき処理としてばＺｎめっきが古くから行
われていたが、最近の防錆能力強化の要請に伴い種々の
Ｚｎ系合金めっきが開発され使用されている。<Conventional technology> Steel plates are widely used in automobiles, home appliances, building materials, etc.
Under normal test conditions, they will rust, so in recent years steel plates that have been plated to prevent rust have been widely used. As a plating treatment, Zn plating has been used for a long time, but in response to recent demands for enhanced rust prevention ability, various Zn-based alloy platings have been developed and used.
Ｚｎ合金めっきは、溶融めっき法によるＺｎ−Ｐａ。Zn alloy plating is Zn-Pa by hot-dip plating.
Ｚｎ−Ｍ、電気めっき法によるＺｎ−！１４、Ｚｎ −
Ｆｅが主に使われているが十分な防＃能力は得られてい
ない、このため様々な新しいめっき処理の研究開発が現
在も行われている。Zn-M, Zn-! by electroplating method. 14, Zn −
Although Fe is mainly used, it has not achieved sufficient anti-# performance, and for this reason, research and development of various new plating treatments is currently being carried out.
ＭｇはＺｎの防錆能を向上させる合金元素として有望で
ありＺｎ−１合金めっきの試みがなされている。Mg is promising as an alloying element that improves the antirust ability of Zn, and attempts have been made to form a Zn-1 alloy plating.
Ｚｎ −Ｆｉｇ合金めっき方法として最初に検討された
のは溶融めっき法であり、特開昭５６−９６０３６号公
報、特開昭５６−１２３３５９号公報、特開昭５６−１
５２９５３号公報、特開昭５６−１５２９５６号公報等
が知られている。The first Zn-Fig alloy plating method studied was the hot-dip plating method, which was disclosed in JP-A-56-96036, JP-A-56-123359, and JP-A-56-1.
52953, JP-A-56-152956, etc. are known.
しかし、ＰＩｇの融点は６５０°ＣでＺｎの融点４１９
°Ｃよりはるかに高いために溶融Ｚｎ浴には少量しか添
加できず、しかもめっき層と鋼板の界面にＦｅｌｌｉ度
の高い合金層ができてめっき密着性が劣化するために色
々な添加元素を入れる必要があり、またａｉ自体も熱で
材料特性が劣化して加工性が悪くなる等の問題があった
。However, the melting point of PIg is 650°C and the melting point of Zn is 419°C.
Since the temperature is much higher than °C, only a small amount can be added to the molten Zn bath, and an alloy layer with a high Felli degree is formed at the interface between the plating layer and the steel sheet, deteriorating the plating adhesion, so various additive elements are added. In addition, AI itself has problems such as its material properties deteriorating due to heat, resulting in poor workability.
蒸着法によるＺｎ −Ｍｇ合金めっきが検討されたが（
特開昭６４−１７８５１号公報、特開昭６４−１７８５
２号公報、特開昭６４−１７８５３号公報参照）、蒸着
法では高い真空度とＨ８、Ｚｎを蒸発させるための大き
な熱源が必要でコストが高いうえに、鋼板との密着性が
良くなくまた緻密で均一なめっき層を得ることが難しい
等の問題があった。Zn-Mg alloy plating by vapor deposition method was considered (
JP-A-64-17851, JP-A-64-1785
(Refer to Publication No. 2 and Japanese Patent Application Laid-Open No. 17853/1983), the vapor deposition method requires a high degree of vacuum and a large heat source to evaporate H8 and Zn, resulting in high cost and poor adhesion to the steel plate. There were problems such as difficulty in obtaining a dense and uniform plating layer.
電気めっき法では、通常の水溶液を使用するとＺｎとＭ
ｇの単種電位が違いすぎるために、合金めっきを得るこ
とが極めて難しい、特開昭５８−１４４４９２号公報で
はフッ化物を使うめっき浴が示されているが、Ｍ、含有
量が１％以下のものしか得られていない。In the electroplating method, Zn and M can be removed using a normal aqueous solution.
It is extremely difficult to obtain alloy plating because the single potentials of g are too different. JP-A-58-144492 discloses a plating bath that uses fluoride, but the M content is 1% or less. I've only been able to get what I want.
〈発明が解決しようとする課題〉
上記のように、従来の方法ではめっき密着性および耐食
性の良いＺｎ −Ｍｇ合金めっき鋼板を得ることはでき
なかった。<Problems to be Solved by the Invention> As described above, it has not been possible to obtain a Zn-Mg alloy plated steel sheet with good plating adhesion and corrosion resistance using conventional methods.
本発明は、このような問題を解決した密着性および耐食
性の優れたＺｎ −Ｍｇ合金めっき鋼板を提供すること
を目的とする。An object of the present invention is to provide a Zn--Mg alloy plated steel sheet with excellent adhesion and corrosion resistance, which solves these problems.
〈課題を解決するための手段〉
本発明のめっき鋼板は、鋼板の少なくとも片面に、Ｍｇ
を１〜３５重量％含有し、めっき層中のＦｅ含有量が０
．５〜２５重量％で残部が実質的にＺｎと不可避的不純
物からなるめっき層をｌθ〜６０ｇ／ｎｆ有することを
特徴とするめっき密着性および耐食性に優れたＺｎ
Ｍｇ合金めっき鋼板であり、また、前記めっき層中のＦ
ｅの含有率が鋼板との界面で最も高く、表面に向かって
漸減し、表面ではＦｅを実質的に含まないことを特徴と
するめっき密着性および耐食性に優れたＺｎ −Ｍｇ合
金めっき鋼板である。また、前記めっき層の上にクロム
付着量２００ｍｇ／ｍ２以下のクロメート処理層を有す
ることを特徴とするめっき密着性および耐食性に優れた
Ｚｎ −Ｍｇ合金めっき鋼板であり、また、前記クロメ
ート処理層の上にシリカゾルを５０重量％以下を含有す
る有機塗膜を２ｎ以下有することを特徴とするめっき密
着性および耐食性に優れたＺｎ −Ｍｇ合金めっき鋼板
である。さらに、前記めっき層が溶融塩電気めっき層で
あることを特徴とするめっき密着性および耐食性に優れ
たＺｎ −Ｍｇ合金めっき鋼板である。<Means for Solving the Problems> The plated steel sheet of the present invention has Mg on at least one side of the steel sheet.
1 to 35% by weight, and the Fe content in the plating layer is 0.
．． Zn with excellent plating adhesion and corrosion resistance, characterized by having a plating layer of 5 to 25% by weight and the remainder consisting essentially of Zn and unavoidable impurities lθ to 60g/nf
It is an Mg alloy plated steel sheet, and F in the plating layer is
A Zn-Mg alloy coated steel sheet with excellent plating adhesion and corrosion resistance, characterized by the highest content of e at the interface with the steel sheet, which gradually decreases toward the surface, and substantially no Fe at the surface. . The present invention also provides a Zn-Mg alloy coated steel sheet with excellent plating adhesion and corrosion resistance, characterized in that it has a chromate treatment layer with a chromium adhesion amount of 200 mg/m2 or less on the plating layer, and This is a Zn-Mg alloy plated steel sheet with excellent plating adhesion and corrosion resistance, characterized by having 2n or less of an organic coating film containing 50% by weight or less of silica sol thereon. Furthermore, the present invention is a Zn-Mg alloy plated steel sheet having excellent plating adhesion and corrosion resistance, characterized in that the plating layer is a molten salt electroplating layer.
本発明のめっき鋼板の製造方法は、Ｚｎ塩化物および１
塩化物、ならびにＮａ、 Ｋ、 Ｌｉの塩化物の１種又
は２種以上からなるめっき浴を用いて温度３５０〜５０
０°Ｃ１電流密度２０〜３５０ Ａ／ｄｄで電気めっき
することを特徴とするめっき密着性および耐食性に優れ
たＺｎ ７ Ｍｇ合金めっき鋼板の製造方法である。The method for manufacturing a plated steel sheet of the present invention includes Zn chloride and 1
Using a plating bath consisting of chloride and one or more of Na, K, and Li chlorides at a temperature of 350 to 50
This is a method for producing a Zn 7 Mg alloy plated steel sheet with excellent plating adhesion and corrosion resistance, which is characterized by electroplating at a current density of 20 to 350 A/dd at 0°C.
く作 用〉
Ｚｎ−ＭＪ合金めっきが優れた耐食性を示す理由は明確
ではないやり、Ｍｇは腐蝕環境下において生じる種々の
Ｚｎ腐蝕生成物のうち腐蝕抑制効果の無いＺｎＯを抑制
し、腐蝕抑制効果のあるＺｎ （ＯＨ） ２、ＺｎＣ０
ｚ等を安定化させるためと考えられる。The reason why Zn-MJ alloy plating exhibits excellent corrosion resistance is not clear, but among the various Zn corrosion products that occur in a corrosive environment, Mg suppresses ZnO, which has no corrosion-inhibiting effect, and has a corrosion-inhibiting effect. Zn (OH) 2, ZnC0 with
This is thought to be to stabilize z, etc.
本発明では合金中のＭｇ含有率は１〜３５重量％、より
好ましくは５〜３５重量％である。Ｍｇ含有率が１％未
満であると耐食性の向上が不十分であり、通常のＺｎめ
っき程度の耐食性しか得られないが、５％以上では良好
な耐食性となる０Ｍｇ含有率が３５％超になると耐食性
向上効果が飽和してしまい、過剰なＭｇの使用は不経済
であるばかりでなくめっき層が跪くなって加工などによ
ってめっき層に割れが入りやすくなり、かえって耐食性
が損なわれることになり好ましくない。In the present invention, the Mg content in the alloy is 1 to 35% by weight, more preferably 5 to 35% by weight. If the Mg content is less than 1%, the improvement in corrosion resistance will be insufficient, and the corrosion resistance will only be comparable to that of ordinary Zn plating, but if the Mg content is 5% or more, good corrosion resistance will be obtained.If the Mg content exceeds 35%, The effect of improving corrosion resistance is saturated, and the use of excessive Mg is not only uneconomical, but also causes the plating layer to collapse and become susceptible to cracking during processing, which in turn impairs corrosion resistance, which is undesirable. .
本発明ではめっき層中にＰｅを０．５〜２５重量％含有
する。めっき層中にＦｅが含有されるとめっき層と鋼板
の密着性が向上するが、Ｆｅ含有量が０．５重量％未満
では密着性向上効果が不十分であり、Ｆｅ含有率が２５
重量％超になると跪くなって密着性が劣化するようにな
るので好ましくない、また、Ｆｅがめつき層表面に存在
すると赤錆の発生が早くなるので、めっき層表面では実
質的にＦｅを含まないことが望ましく、かつＦｅ含有率
が鋼板界面で最も高くめっき表面に向かって漸減すると
、より良いめっき密着性と耐食性が得られる。In the present invention, the plating layer contains 0.5 to 25% by weight of Pe. When Fe is contained in the plating layer, the adhesion between the plating layer and the steel sheet is improved, but if the Fe content is less than 0.5% by weight, the effect of improving adhesion is insufficient, and if the Fe content is less than 25% by weight,
If it exceeds % by weight, it is undesirable as it will lead to deterioration of adhesion.Furthermore, if Fe exists on the surface of the plating layer, red rust will occur more quickly, so the surface of the plating layer should be substantially free of Fe. is desirable, and when the Fe content is highest at the steel plate interface and gradually decreases toward the plated surface, better plating adhesion and corrosion resistance can be obtained.
本発明＃板のめっき量の範囲は１０〜６０ｇ／ｒｒｆで
ある。めっき量が１０ｇ／ｒｒｆ未満であると耐食性が
不十分である。めっき量は多いほど耐食性は良好である
が、６０ｇ／ｍ超になると耐食性能に対しコストが過剰
にかかり、不経済であるばかりでなく溶接性、加工性等
が損なわれるので望ましくない。The range of the plating amount of the # plate of the present invention is 10 to 60 g/rrf. If the plating amount is less than 10 g/rrf, corrosion resistance will be insufficient. The larger the amount of plating, the better the corrosion resistance, but if it exceeds 60 g/m, it is not desirable because it is not only uneconomical but also causes excessive cost compared to the corrosion resistance performance, and impairs weldability, workability, etc.
上記本発明の鋼板はそれ自体で優れた耐食性を有するが
、さらに優れた耐食性を得るために、上述のめっき層上
にクロメート層を設けることもできる。クロメート層は
めっき鋼板を腐蝕環境から保護して耐食性を向上させる
。クロメート量はクロム付着量で２００■／ポ以下であ
る。クロム付着量は多いほど耐食性は良くなるが、２０
０ｍｇ／ｍ２超になると耐食性を向上させる効果が飽和
してしまい不経済になるばかりでなく色調が黄色になる
ので好ましくない、クロメート処理を施すにはクロメー
ト液を塗布乾燥する方法や電解法などいずれでも良く特
に限定するものではない。The steel sheet of the present invention has excellent corrosion resistance by itself, but in order to obtain even better corrosion resistance, a chromate layer can be provided on the above-mentioned plating layer. The chromate layer protects the plated steel sheet from corrosive environments and improves its corrosion resistance. The amount of chromate deposited is 200 μ/Po or less. The greater the amount of chromium deposited, the better the corrosion resistance, but 20
If it exceeds 0 mg/m2, the effect of improving corrosion resistance will be saturated, which will not only make it uneconomical but also cause the color to turn yellow, which is undesirable.To perform chromate treatment, there are two methods: coating and drying a chromate solution, electrolytic method, etc. However, it is not particularly limited.
本発明ではさらなる耐食性の向上のために、クロメート
処理層の上にシリカゾルを５０重量％以下含有する有機
’！！ＩＩを２１ｒｍ以下施すこともできる。In the present invention, in order to further improve corrosion resistance, organic '! ! II can also be applied at 21 rm or less.
２ｎ以下の有機塗膜では皮膜がポーラスなので保護皮膜
としての効果はないが腐蝕環境下で腐蝕生成物を保持し
て耐食性を向上させる。有機塗膜厚は厚いほうが耐食性
を向上させるが、２ｎＢになると耐食性は良いが溶接性
が著しく劣化するので望ましくない、シリカゾルは塗膜
中で腐蝕生成物を強固に保持して耐食性を向上させるが
、５０重量％超になると溶接性が低下するので望ましく
ない。An organic coating film of 2n or less is porous and therefore has no effect as a protective film, but it retains corrosion products in a corrosive environment and improves corrosion resistance. The thicker the organic coating, the better the corrosion resistance; however, a thickness of 2nB is undesirable because the corrosion resistance is good but the weldability deteriorates markedly.Silica sol strongly holds corrosion products in the coating and improves the corrosion resistance. If it exceeds 50% by weight, weldability deteriorates, which is not desirable.
有Ｉｌ塗膜の形成方法は通常のロールコータ−塗布、熱
風乾燥で行えば良いが、特に形成方法を限定するもので
はない。The Il-containing coating film may be formed by conventional roll coater coating and hot air drying, but the forming method is not particularly limited.
クロメート層、有機！ｔＭは目的、使用用途に応じて用
いれば良い。Chromate layer, organic! tM may be used depending on the purpose and usage.
上記の本発明の鋼板のＺｎ −Ｍｇ合金めっき鋼板のめ
っき層は、溶融塩電気めっき層であることが好ましい。The plating layer of the Zn-Mg alloy plated steel sheet of the steel sheet of the present invention is preferably a molten salt electroplating layer.
本発明者らは、Ｚｎ −Ｍｇ合金めっきが鋼板に対し優
れた防錆力を発揮するためには、合金中のＭ、Ｊ含有量
が一定量以上必要であることから、Ｍｇ含有量を多くで
きるめっき方法が重要であると考えた。The present inventors discovered that in order for Zn-Mg alloy plating to exhibit excellent rust prevention properties on steel sheets, the M and J contents in the alloy must be at a certain level or higher. We thought that the plating method that can be used is important.
そこで種々検討した結果、溶融塩を用いた電気めっきが
最も適していることを見出した０通常の水溶液を使う電
気めっきでは、Ｍ、とＺｎの単極電位が違い過ぎること
とＭｇの単極電位が大きく卑であるために、合金中には
掻く微量しかＭｇは含有されない、これに対し溶融塩を
用いる電気めっきではこのようなことはなく、浴中の１
イオン量に応じて合金中に１が含有される。また溶融塩
浴では高い電流密度でめっきできるので、高い生産性も
期待できる。As a result of various studies, we found that electroplating using molten salt is the most suitable. 0. In electroplating using a normal aqueous solution, the unipolar potentials of M and Zn are too different, and the unipolar potential of Mg is too different. Since Mg is highly base, only a trace amount of Mg is contained in the alloy.On the other hand, this does not occur in electroplating using molten salt;
1 is contained in the alloy depending on the amount of ions. Furthermore, since plating can be performed at a high current density in a molten salt bath, high productivity can be expected.
溶融塩電気めっき法はまためっき層中のＭｇ含有量の制
御が容易で、かつめうき中に鋼板からのＦｅの拡散によ
り表面に向かって漸減するようにＰｅが含有されるので
、本発明のめっき鋼板の製造に最も適している。In the molten salt electroplating method, the Mg content in the plating layer can be easily controlled, and Pe is contained during plating so that it gradually decreases toward the surface due to the diffusion of Fe from the steel sheet. Most suitable for manufacturing galvanized steel sheets.
溶融塩としてはフッ化物や硝酸塩を用いた浴もあるが、
比較的低温でめっきでき、かつ爆発や腐蝕の危険性の少
ない塩化物浴が最も優れていることが分かった０本発明
の溶融塩浴は、Ｚｎ塩化物およびＭｇ塩化物、ならびに
Ｎａ、 Ｋ、、Ｌｉの塩化物の１種または２種以上から
なっている。 Ｚｎ塩化物、Ｍｇ塩化物はＺｎイオン、
Ｍ、イオンの供給源であり、Ｎａ、Ｋ、Ｌｉの塩化物は
伝導剤および融点降下剤として作用する。めっき浴中の
各塩化物の比率は、目標のＭｇ含有率に応じて任意に決
めればよく特には限定されない。There are also baths that use fluoride or nitrate as molten salt,
It has been found that a chloride bath that allows plating at a relatively low temperature and has little risk of explosion or corrosion is the best.The molten salt bath of the present invention contains Zn chloride and Mg chloride, as well as Na, K, , one or more chlorides of Li. Zn chloride and Mg chloride are Zn ions,
M is a source of ions, and the chlorides of Na, K, and Li act as conductive agents and melting point depressants. The ratio of each chloride in the plating bath may be arbitrarily determined depending on the target Mg content and is not particularly limited.
めっき温度は３５０〜５００℃である。めっき温度が３
５０℃未満であるとめっき浴が凝固しかかるために満足
なめっきができず、５００°Ｃ超になるとめっき浴から
発煙するようになるだけでなくＦｅの拡散が大きくなっ
てＦｅ含有率が２５重量％を趨えるようになりまた鋼板
自体の材料特性が劣化するので好ましくない。The plating temperature is 350-500°C. Plating temperature is 3
If the temperature is less than 50°C, the plating bath will begin to solidify, making it impossible to achieve satisfactory plating. If the temperature exceeds 500°C, not only will the plating bath start to emit smoke, but the Fe content will increase to 25%. This is undesirable because the weight percentage will increase and the material properties of the steel sheet itself will deteriorate.
めっきの際の電解電流密度は２０〜３５０ Ａ／ｄｊで
ある。電流密度が２０Ａ／ｄｊ未満では満足なめっきが
形成されず、３５０ Ａ ／−趨になると電流を流すた
めに過大な電圧を要するばかりでなく電気抵抗熱で鋼板
が発熱して浴温度が上昇してしまうので好ましくない。The electrolytic current density during plating is 20 to 350 A/dj. If the current density is less than 20 A/dj, satisfactory plating will not be formed, and if it reaches 350 A/dj, not only will an excessive voltage be required to flow the current, but the steel sheet will generate heat due to electrical resistance heat, and the bath temperature will rise. This is not desirable because it causes
〈実施例〉 次に、本発明の実施例および比較例について説明する。<Example> Next, examples and comparative examples of the present invention will be described.
冷延鋼板を通常の脱脂、酸洗したのち非酸化性雰囲気中
で乾燥し、めっき温度まで余熱し直ちに下記のＡ−Ｄの
熔融塩めっき浴でＺｎ−Ｍｇ合金めっきを行い、さらに
一部の鋼板にはクロメート処理、有機塗布を行って各種
Ｚｎ −Ｍｇ合金めっき鋼板を作成した。After degreasing and pickling the cold-rolled steel sheet, it is dried in a non-oxidizing atmosphere, preheated to the plating temperature, and immediately subjected to Zn-Mg alloy plating in the following molten salt plating baths A-D. The steel plates were subjected to chromate treatment and organic coating to create various Zn-Mg alloy plated steel plates.
（めっき浴Ａ）
’ＺｎＣ１ｚ ６３．００−％Ｍｇｃｊ、
ｓ、ｏｏＷｉ％
ＮａＣ１３０，００−％
ＫＣＩ ２．００−％
（めっき浴Ｂ）
ＺｎＣ１ｘ ６１．００−％
ＭｇＣＺ寞 ９．００−％
ＮａＣ１２６，００−％
ＫＣＩ ４．００−％
１めっき浴Ｃ）
ＺｎｌＪｚ ６０．４０−％
ＨｇＣ１ｔ ４．６０−％
ＮａＣ１２８，６０−％
ＭＣＩ １．８０−％
ＬｉＣＺ ４．６０−％
（めっき浴Ｄ）
ＺｎＣ１１５５，３０−％
ＨｇＣ１ｍ １６．８０−％
ＮａＣ１２６，２０−％
ＭＣＩ １．７０−％
（めっき浴Ｅ）
ＺｎＣ１＊ ６６．３５−％
？ＩｇＣＺ、 ０．２５−％
ＮａＣ１３１，４０−％
ＭＣＩ ２．００−％
（クロメート処理１
リバース式ロールコータ−で日本バー力うイジング■製
クロメート液４５１３ Ｈを塗布し、１１０℃×２０算
の乾燥を行った。(Plating bath A) 'ZnC1z 63.00-% Mgcj,
s,ooWi% NaC130,00-% KCI 2.00-% (Plating bath B) ZnC1x 61.00-% MgCZ-9.00-% NaC126,00-% KCI 4.00-% 1 Plating bath C) ZnlJz 60.40-% HgC1t 4.60-% NaC128, 60-% MCI 1.80-% LiCZ 4.60-% (Plating bath D) ZnC1155, 30-% HgC1m 16.80-% NaC126, 20-% MCI 1.70-% (Plating bath E) ZnC1* 66.35-%? IgCZ, 0.25-% NaC131,40-% MCI 2.00-% (Chromate treatment 1 Apply chromate solution 4513 H manufactured by Nippon Bar Uising ■ with a reverse roll coater and dry at 110°C x 20 times. I did it.
（有機皮膜塗布）
リバース式ロールコータ−９でエポキシウレタン系有機
樹脂とシリカゾルを混合した塗布液を塗布し、１５０°
ＣＸ３０ｓｅｃの乾燥を行った。(Organic film application) Apply a coating solution containing a mixture of epoxy urethane organic resin and silica sol using a reverse roll coater 9, and
CX drying was performed for 30 seconds.
（めっき密着性評価）
１８０度曲げテープ剥離法によりめっき剥離量を評価し
た。(Evaluation of plating adhesion) The amount of plating peeled off was evaluated by the 180 degree bending tape peeling method.
（評価） ◎：めっき剥離なし ０：めっき剥離率 ×；めっき剥離量 （耐食性評価） 塩水噴霧試験により赤錆発生時間を測定した。(Evaluation) ◎: No plating peeling 0: Plating peeling rate ×; Amount of plating peeled off (Corrosion resistance evaluation) The red rust generation time was measured by a salt spray test.
各鋼板の諸性能を示した表１から明らかなように、本発
明のＺｎ −Ｍｇ合金めっき鋼板は優れためつき密着性
および耐食性を示す。As is clear from Table 1 showing the various performances of each steel sheet, the Zn-Mg alloy plated steel sheet of the present invention exhibits excellent tamping adhesion and corrosion resistance.
〈発明の効果〉
以上のように本発明のＺｎ −Ｍｇ合金めっき鋼板は、
充分な量のＭ、と適量なＦｅを含有しているので、優れ
ためっき密着性と耐食性が得られ、またＦｅ含有量が鋼
板界面から表面に向かって漸減しめっき表面では実質的
にＦｅを含まないのでより良いめっき密着性と耐食性が
得られる。まためっき層上のクロメート層によりさらに
優れた耐食性が得られ、最上層にシリカゾルを含有する
有機塗膜層によりさらなる優れた耐食性が得られる。<Effects of the Invention> As described above, the Zn-Mg alloy plated steel sheet of the present invention has the following effects:
Since it contains a sufficient amount of M and an appropriate amount of Fe, excellent plating adhesion and corrosion resistance can be obtained, and the Fe content gradually decreases from the steel plate interface to the surface, virtually eliminating Fe on the plated surface. Better plating adhesion and corrosion resistance can be obtained because it does not contain Further, the chromate layer on the plating layer provides even better corrosion resistance, and the top layer of the organic coating layer containing silica sol provides even better corrosion resistance.
特許出願人 川崎製鉄株式会社Patent applicant: Kawasaki Steel Corporation
Claims (6)
含有し、めっき層中のＦｅ含有量が０．５〜２５重量％
で残部が実質的にＺｎと不可避的不純物からなるめっき
層を１０〜６０ｇ／ｍ＾２有することを特徴とするめっ
き密着性および耐食性に優れたＺｎ−Ｍｇ合金めっき鋼
板。(1) 1 to 35% by weight of Mg on at least one side of the steel plate
Fe content in the plating layer is 0.5 to 25% by weight.
A Zn-Mg alloy coated steel sheet with excellent plating adhesion and corrosion resistance, characterized by having a plating layer of 10 to 60 g/m^2 with the remainder essentially consisting of Zn and unavoidable impurities.
高く、表面に向かって漸減し、表面ではＦｅを実質的に
含まないことを特徴とする請求項（１）記載のめっき密
着性および耐食性に優れたＺｎ−Ｍｇ合金めっき鋼板。(2) The plating adhesion according to claim (1), characterized in that the content of Fe in the plating layer is highest at the interface with the steel plate, gradually decreases toward the surface, and substantially contains no Fe at the surface. Zn-Mg alloy plated steel sheet with excellent strength and corrosion resistance.
以下のクロメート処理層を有することを特徴とする請求
項（１）又は（２）記載のめっき密着性および耐食性に
優れたＺｎ−Ｍｇ合金めっき鋼板。(3) Amount of chromium deposited on the plating layer: 200mg/m^2
A Zn-Mg alloy plated steel sheet with excellent plating adhesion and corrosion resistance according to claim 1 or 2, characterized by having the following chromate treatment layer.
以下を含有する有機塗膜を２μｍ以下有することを特徴
とする請求項（３）記載のめっき密着性および耐食性に
優れたＺｎ−Ｍｇ合金めっき鋼板。(4) 50% by weight of silica sol on top of the chromate treatment layer
A Zn-Mg alloy plated steel sheet with excellent plating adhesion and corrosion resistance according to claim 3, characterized in that the organic coating film has a thickness of 2 μm or less and contains the following:
とする請求項（１）、（２）、（３）および（４）のい
ずれか記載のめっき密着性および耐食性に優れたＺｎ−
Ｍｇ合金めつき鋼板。(5) The Zn-plating layer having excellent plating adhesion and corrosion resistance according to any one of claims (1), (2), (3) and (4), wherein the plating layer is a molten salt electroplating layer.
Mg alloy plated steel plate.
、Ｌｉの塩化物の１種又は２種以上からなるめっき浴を
用いて温度３５０〜５００℃、電流密度２０〜３５０Ａ
／ｄｍ＾２で電気めっきすることを特徴とするめっき密
着性および耐食性に優れたＺｎ−Ｍｇ合金めっき鋼板の
製造方法。(6) Zn chloride and Mg chloride, as well as Na, K
, using a plating bath consisting of one or more chlorides of Li at a temperature of 350 to 500°C and a current density of 20 to 350 A.
A method for producing a Zn-Mg alloy coated steel sheet with excellent plating adhesion and corrosion resistance, which comprises electroplating at /dm^2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30710090A JPH04180592A (en) | 1990-11-15 | 1990-11-15 | Zn-mg alloy plated steel sheet excellent in plating adhesion and corrosion resistance and its production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30710090A JPH04180592A (en) | 1990-11-15 | 1990-11-15 | Zn-mg alloy plated steel sheet excellent in plating adhesion and corrosion resistance and its production |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04180592A true JPH04180592A (en) | 1992-06-26 |
Family
ID=17965030
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30710090A Pending JPH04180592A (en) | 1990-11-15 | 1990-11-15 | Zn-mg alloy plated steel sheet excellent in plating adhesion and corrosion resistance and its production |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04180592A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7343874B2 (en) | 2002-08-07 | 2008-03-18 | The Clorox Company | Silica gel based animal litter |
| JP2019151720A (en) * | 2018-03-02 | 2019-09-12 | 東ソー株式会社 | Composition, manufacturing method, and application thereof |
| CN113227437A (en) * | 2018-12-19 | 2021-08-06 | Posco公司 | Dissimilar plated steel sheet having excellent workability and corrosion resistance and method for producing same |
-
1990
- 1990-11-15 JP JP30710090A patent/JPH04180592A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7343874B2 (en) | 2002-08-07 | 2008-03-18 | The Clorox Company | Silica gel based animal litter |
| JP2019151720A (en) * | 2018-03-02 | 2019-09-12 | 東ソー株式会社 | Composition, manufacturing method, and application thereof |
| CN113227437A (en) * | 2018-12-19 | 2021-08-06 | Posco公司 | Dissimilar plated steel sheet having excellent workability and corrosion resistance and method for producing same |
| CN113227437B (en) * | 2018-12-19 | 2023-06-30 | 浦项股份有限公司 | Heterogeneous plated steel sheet excellent in workability and corrosion resistance and method for producing same |
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