JP2698549C - - Google Patents
Info
- Publication number
- JP2698549C JP2698549C JP2698549C JP 2698549 C JP2698549 C JP 2698549C JP 2698549 C JP2698549 C JP 2698549C
- Authority
- JP
- Japan
- Prior art keywords
- steel sheet
- coating
- oxide
- silicon steel
- aluminum oxide
- 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
- 239000011248 coating agent Substances 0.000 claims description 55
- 238000000576 coating method Methods 0.000 claims description 55
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 43
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 40
- 229910000976 Electrical steel Inorganic materials 0.000 claims description 29
- PNEYBMLMFCGWSK-UHFFFAOYSA-N al2o3 Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 22
- 229910052742 iron Inorganic materials 0.000 claims description 20
- 239000000395 magnesium oxide Substances 0.000 claims description 20
- 238000000137 annealing Methods 0.000 claims description 18
- 239000002131 composite material Substances 0.000 claims description 12
- 229910052596 spinel Inorganic materials 0.000 claims description 12
- 239000011029 spinel Substances 0.000 claims description 12
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 10
- 229910052710 silicon Inorganic materials 0.000 claims description 10
- 239000010703 silicon Substances 0.000 claims description 10
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 7
- 229910052796 boron Inorganic materials 0.000 claims description 7
- OAICVXFJPJFONN-UHFFFAOYSA-N phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 5
- 229910052698 phosphorus Inorganic materials 0.000 claims description 5
- 239000011574 phosphorus Substances 0.000 claims description 5
- GSWGDDYIUCWADU-UHFFFAOYSA-N [O--].[Mg++].[Al+3] Chemical compound [O--].[Mg++].[Al+3] GSWGDDYIUCWADU-UHFFFAOYSA-N 0.000 claims description 4
- CNGGOAOYPQGTLH-UHFFFAOYSA-N [O-2].[O-2].[Mg+2].[Al+3] Chemical compound [O-2].[O-2].[Mg+2].[Al+3] CNGGOAOYPQGTLH-UHFFFAOYSA-N 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminum Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 229910000831 Steel Inorganic materials 0.000 description 31
- 239000010959 steel Substances 0.000 description 31
- 235000012245 magnesium oxide Nutrition 0.000 description 18
- 150000001875 compounds Chemical class 0.000 description 13
- 239000012071 phase Substances 0.000 description 13
- OZAIFHULBGXAKX-UHFFFAOYSA-N precursor Substances N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 description 12
- 239000000843 powder Substances 0.000 description 9
- 239000000126 substance Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 239000002002 slurry Substances 0.000 description 6
- 239000012298 atmosphere Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 4
- 229910001593 boehmite Inorganic materials 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000002441 X-ray diffraction Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 238000005452 bending Methods 0.000 description 3
- 239000002612 dispersion media Substances 0.000 description 3
- 239000012153 distilled water Substances 0.000 description 3
- 229910052839 forsterite Inorganic materials 0.000 description 3
- 230000005381 magnetic domain Effects 0.000 description 3
- 239000012299 nitrogen atmosphere Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- VSCWAEJMTAWNJL-UHFFFAOYSA-K Aluminium chloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 2
- YIXJRHPUWRPCBB-UHFFFAOYSA-N Magnesium nitrate Chemical compound [Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YIXJRHPUWRPCBB-UHFFFAOYSA-N 0.000 description 2
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L MgCl2 Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 238000005755 formation reaction Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 159000000003 magnesium salts Chemical class 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- WNROFYMDJYEPJX-UHFFFAOYSA-K Aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 1
- JLDSOYXADOWAKB-UHFFFAOYSA-N Aluminium nitrate Chemical compound [Al+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O JLDSOYXADOWAKB-UHFFFAOYSA-N 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N Boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- VTHJTEIRLNZDEV-UHFFFAOYSA-L Magnesium hydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 1
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K [O-]P([O-])([O-])=O Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- SHHIADHOJKLUIZ-UHFFFAOYSA-N azane;molecular hydrogen Chemical compound N.[H][H] SHHIADHOJKLUIZ-UHFFFAOYSA-N 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- 239000004327 boric acid Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 229910052803 cobalt Inorganic materials 0.000 description 1
- 239000008119 colloidal silica Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000011162 core material Substances 0.000 description 1
- WMWXXXSCZVGQAR-UHFFFAOYSA-N dialuminum;oxygen(2-);hydrate Chemical compound O.[O-2].[O-2].[O-2].[Al+3].[Al+3] WMWXXXSCZVGQAR-UHFFFAOYSA-N 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000001493 electron microscopy Methods 0.000 description 1
- 238000001962 electrophoresis Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atoms Chemical class [H]* 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000001678 irradiating Effects 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910001629 magnesium chloride Inorganic materials 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N oxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】
本発明は、鋼板に大きな張力を付与する被膜を表面に有することで、鉄損が低
減された一方向性珪素鋼板に関する。
【０００２】
【従来の技術】
一方向性珪素鋼板は、（１１０），〔００１〕を主方位とする結晶組織を有し
、磁気鉄芯材料として多用されており、特にエネルギーロスを少なくするために
鉄損の小さい材料が求められている。一方向性珪素鋼板の鉄損を低減する手段と
しては、仕上げ焼鈍後の鋼板表面にレーザービームを照射して局部的な歪を与え
、それによって磁区を細分化する方法が特開昭５８−２６４０５号公報に開示さ
れている。また鉄芯加工後の歪取り焼鈍（応力除去焼鈍）を施した後もその効果
が消失しない磁区細分化手段が、例えば特開昭６２−８６１７５号公報に開示さ
れている。
【０００３】
一方で、鉄および珪素を含有する鉄合金は結晶磁気異方性が大きいため、外部
張力を付加すると磁区の細分化が起こり、鉄損の主要素である渦電流損失を低下
させることができる。したがって、５％以下の珪素を含有する一方向性珪素鋼板
の鉄損の低減には鋼板に張力を付与することが有効であり、１．５kgf/mm2程度
までの張力付与によって効果的に鉄損が低減できることが知られている。この張
力は通常、表面に形成された被膜によって付与されている。
【０００４】
従来、一方向性珪素鋼板には、仕上げ焼鈍工程で鋼板表面の酸化物と焼鈍分離
剤とが反応して生成するフォルステライトを主体とする１次被膜、および特開昭
４８−３９３３８号公報等に開示されたコロイド状シリカとりん酸塩とを主体と
するコーティング液を焼き付けることによって生成する２次被膜の２層の被膜に
よって１．０kgf/mm2程度の張力が付与されている。したがって、これら現行被
膜の場合、より大きな張力付与による鉄損改善の余地は残されているものの、被
膜を厚くすることによる付与張力の増加は占積率の低下をもたらすため好ましく
ない。
【０００５】
また、一方向性珪素鋼板の鉄損を改善するもうひとつの方法として、仕上げ焼
鈍後の鋼板表面の凹凸や表面近傍の内部酸化層を除去して鏡面仕上げを行い、そ
の表面に金属メッキを施す方法が特公昭５２−２４４９９号公報に、さらにその
表面に張力被膜を形成する方法が例えば特公昭５６−４１５０号公報、特開昭６
１−２０１７３２号公報、特公昭６３−５４７６７号公報、特開平２−２１３４
８８号公報等に開示されている。これらの場合においても、被膜による鋼板への
張力付与の大きい方が鉄損改善効果が大きい。これらのことから、密着性に優れ
、薄くて鋼板に大きな張力が付与できる被膜が望まれていた。
【０００６】
【発明が解決しようとする課題】
本発明は、これら従来技術における問題点を解決し、鋼板に大きな張力を付与
する被膜を表面に有することにより鉄損が低減された一方向性珪素鋼板を提供す
ることを目的とする。
【０００７】
【課題を解決するための手段】
本発明は、仕上げ焼鈍後の表面に、酸化マグネシウム、酸化アルミニウムそ
れぞれの成分を被膜全体に対する重量割合で１０重量％以上含有してなる、酸化
マグネシウム−酸化アルミニウム系複合被膜を有する一方向性珪素鋼板、酸化
マグネシウム−酸化アルミニウム系複合被膜が結晶質スピネルを含有する一方向
性珪素鋼板、仕上げ焼鈍後の表面に酸化マグネシウム−酸化アルミニウム−非
晶質酸化物系複合被膜を有する一方向性珪素鋼板、酸化マグネシウム−酸化ア
ルミニウム−非晶質酸化物系複合被膜が、結晶質スピネル、および／または珪素
、ほう素、りんの少なくとも１種を成分として含む非晶質相を含有する一方向性
珪素鋼板を要旨とする。
【０００８】
【作用】
以下に本発明を詳細に説明する。
本発明の一方向性珪素鋼板は、その表面に酸化マグネシウム−酸化アルミニウ
ム系複合被膜を有している。従来より、珪素鋼板への張力付与には熱膨張係数の
小さい被膜材質を選択し、鋼板との熱膨張係数差によって冷却時に生じる応力を
利用していた。しかしながら、熱膨張係数だけではなく、被膜材質のヤング率も
鋼板への張力付与に影響をおよぼす因子であることが指摘されている。本発明の
被膜構成成分の役割を明確に規定することは不可能であるが、酸化アルミニウム
成分はヤング率が比較的大きく、これに酸化マグネシウムを複合化することで鋼
板に大きな張力が付与されていると推察している。
【０００９】
酸化マグネシウムはペリクレースとよばれるものだけが結晶相として知られて
いるが、酸化アルミニウムには、α−，γ−，δ−，θ−等いくつかの結晶系が
存在し、鋼板への張力付与効果はそれぞれの結晶系において必ずしも同一ではな
い。しかしながら、本発明の酸化アルミニウムはこのいずれであっても差し支え
ない。またいずれの化合物とも必ずしも良好な結晶性を有する結晶である必要は
なく、結晶性のあまり良くない非晶質的なもの、あるいは結晶の前駆体となるよ
うな化合物であっても構わない。
【００１０】
またこれらの被膜中に結晶質スピネルを含有することでより大きな張力付与が
可能となる場合がある。スピネルは、ＭｇＯ・Ａｌ2Ｏ3の化学式で表記される結
晶であり、すでに述べた低熱膨張係数、高いヤング率という性質によって鋼板に
対して高い張力付与をもたらしていると推察される。スピネルには１：１組成を
中心にアルミナ過剰側に固溶域が存在することが知られているが、本発明の被膜
中に存在する結晶質スピネルは、定比組成、固溶体のいずれであってもまったく
支障なく用いることができる。
【００１１】
本発明の複合被膜中の酸化マグネシウムと酸化アルミニウムの存在割合は、比
較的幅広い範囲とすることが可能であり、いかなる割合とすることもできる。し
かしながら複合被膜の特長を最大限に発揮させるためにはそれぞれの成分を最低
でも被膜全体に対する重量割合で５％、好ましくは１０％以上含有させるのが良
い。また、結晶質スピネルの量もいかなる割合とすることもでき、この化合物を
できるだけ多く含有させることでより高い張力の付与が可能となるが、被膜の表
面性状が悪くなる傾向があるため、必要に応じて最適な量を決定することが好ま
しい。結晶質スピネルの好ましい含有量としては、被膜全体に対する重量割合で
９０％以下、より好ましくは８０％以下であり、通常は、５〜７５％程度の範囲
から選択される。
【００１２】
本発明のもうひとつの一方向性珪素鋼板表面には、酸化マグネシウム−酸化ア
ルミニウム−非晶質酸化物系複合被膜を有している。酸化マグネシウム成分、酸
化アルミニウム成分の役割はすでに述べたとおりであるが、非晶質酸化物成分の
役割として、鋼板への張力付与にはそれほど大きな効果はなく、表面平滑性、下
地鋼板との密着性等を大きく改善していると推察している。なかでも、珪素、ほ
う素、りんの少なくとも１種を成分として含む非晶質相がとりわけこの効果が顕
著であることを見い出した。特にガラス状物質を形成しているときに著しく大き
な効果が得られる。非晶質相中の珪素、ほう素、りんの含有量は、それぞれの酸
化物換算の合計で非晶質相全体に対する重量割合で５０％以上、好ましくは７０
％以上である。
【００１３】
また、非晶質相には、珪素、ほう素、りん以外に微量の成分を含有していても
一向に差し支えない。可能性のある元素としては、被膜主成分であるＡｌ，Ｍｇ
、母材構成成分であるＦｅ、１次被膜成分であるＴｉ，Ｍｎ，Ｓの他に、Ｌｉ，
Ｎａ，Ｋ，Ｃａ，Ｓｒ，Ｂａ，Ｖ，Ｃｒ，Ｎｉ，Ｃｏ，Ｃｕをはじめとするアル
カリ金属、アルカリ土類金属、遷移金属元素、あるいはＳｎ，Ｐｂ，Ｂｉ，Ｓｂ
等があげられる。
非晶質相全体としての含有量は特に制限はないが、あまり多くなりすぎると鋼
板への張力付与が十分でなくなるため、被膜全体に対する重量割合で９０％以下
、より好ましくは７０％以下である。また少なすぎる場合には、十分に平滑な被
膜表面、良好な密着性が得られない場合があるため、被膜全体に対する重量割合
で５％以上、より好ましくは１０％以上含有することが望ましい。
【００１４】
本発明の一方向性珪素鋼板表面の被膜は、厚すぎる場合には占積率が低下する
ため目的に応じてできるだけ薄いものが良く、ひとつの目安としては鋼板厚さの
５％以下である。より好ましくは、鋼板厚さの２％以下である。また張力付与の
観点からは、極端に薄くては十分な効果が得られず、０．１μｍ以上が望ましい
。
以下に、本発明の一方向性珪素鋼板を好適に製造する方法について述べる。
【００１５】
仕上げ焼鈍が完了した鋼板表面に、酸化マグネシウム前駆体化合物、酸化アル
ミニウム前駆体化合物を含む懸濁液を塗布、乾燥後、５００〜１３５０℃の温度
で焼き付け、酸化物被膜を形成することによる製造方法である。
ここでいう仕上げ焼鈍が完了した鋼板とは、：従来公知の方法によって仕上
げ焼鈍を行い、表面にフォルステライト質の１次被膜が形成された鋼板、：１
次被膜、および付随的に生成している酸化層を酸に浸漬して除去した鋼板、：
で得た鋼板を水素中で平坦化焼鈍を行った鋼板、あるいは化学研磨、電解研磨
等の研磨を施した鋼板、：被膜生成に対して不活性であるアルミナ粉末等、ま
たは塩化物等の微量添加物を添加した従来公知の焼鈍分離剤を塗布し、１次被膜
を生成させない条件下で仕上げ焼鈍を行った鋼板、等を指す。
【００１６】
酸化マグネシウム前駆体化合物は、焼き付け後（熱処理）に酸化マグネシウム
となる化合物の総称であり、酸化マグネシウムはもとより、水酸化マグネシウム
、あるいは硝酸マグネシウム、塩化マグネシウムをはじめとする各種のマグネシ
ウム塩等を指す。酸化アルミニウム前駆体化合物も同様に焼き付け後（熱処理）
に酸化アルミニウムとなる化合物の総称であり、酸化アルミニウムはもとより、
ベーマイトのようなＡｌ2Ｏ3・ｎＨ2Ｏで表記される酸化アルミニウムの水和物
、水酸化アルミニウム、あるいは硝酸アルミニウム、塩化アルミニウムをはじめ
とする各種のアルミニウム塩等を含む。
【００１７】
これらの原料を分散媒に分散させて懸濁液（スラリー）を作製する。分散媒は
作業性、コスト等の点から水が最も好適であるが、他の工程で特に支障がなけれ
ば有機溶媒、あるいはこれらの混合物が使用できる。スラリーを作製した時点で
原料のうちのある種のものは溶解する可能性があるが、これは一向に差し支えな
い。
【００１８】
こうして得たスラリーをロールコーター等のコーター、ディップ法、スプレー
吹き付け、あるいは電気泳動等従来公知の方法によって仕上げ焼鈍が完了した一
方向性珪素鋼板表面に塗布する。乾燥後、５００〜１３５０℃で焼き付けること
によって表面に酸化物被膜を形成する。焼き付け時の雰囲気は、窒素等の不活性
ガス雰囲気、窒素−水素混合雰囲気等の還元雰囲気が好ましく、空気、あるいは
酸素を含む雰囲気は鋼板を酸化させる可能性があり、好ましくない。雰囲気ガス
の露点については特に制限はない。焼き付け温度が５００℃未満の場合、塗布し
た前駆体が酸化物とならない場合があり、また焼き付け温度が低いため十分な張
力が発現せず、好ましくない。一方、１３５０℃を超える場合、特に大きな不都
合はないものの経済的でなく、より好ましくは１２５０℃以下である。
【００１９】
前述のスラリーのうち、酸化アルミニウム前駆体として、いわゆるゾルとよば
れる微粒子分散系を用いることにより薄くて均一、かつ密着性の良い被膜が得ら
れる場合がある。これは表面に非金属物質が存在せず、金属面上に直接被膜を形
成するような場合に特に顕著である。かかるときには上述の微粒子分散系ゾル、
あるいは可溶性成分を含んだゾルが好適に用いられる。
塗布液としてゾル溶液を用いる場合には、酸化アルミニウム前駆体化合物とし
て上述のベーマイトゾル、および／またはアルミナゾルとよばれているものが作
業性、あるいは価格の点から特に好適に用いられる。
【００２０】
酸化アルミニウム前駆体化合物として酸化アルミニウム前駆体ゾルを用いる場
合、酸化マグネシウム前駆体化合物としては気相法等によって作製した酸化マグ
ネシウム超微粉末、液相法等によって作製した微粉末あるいはそれを分散させた
ままの状態のもの、可溶性マグネシウム塩類を用いることが好ましく、これによ
ってきわめてミクロなレベルでの均一混合が実現する。
酸化アルミニウム前駆体ゾルの使用においても、前述のスラリーの場合と同様
に分散媒、特に水に分散させて使用することが可能である。特に良好な分散性を
得るために、酸、アルカリ等の添加による塗布液のｐＨ制御等はしばしば用いら
れる手法であり、本発明においても特に支障なく行うことができる。また、鋼板
への塗布性を改善するための極微量の界面活性剤等の添加についてもまったく問
題がない。
以下に本発明を実施例を用いて具体的に説明するが、本発明はかかる実施例に
のみ限定されるものではない。
【００２１】
【実施例】
実施例１
市販の酸化マグネシウム微粉末、酸化アルミニウム粉末（α−Ａｌ2Ｏ3）を表
１に示した割合に混合し、これに蒸留水を加えてスラリーを作製した。これを、
Ｓｉを３．２％含有する厚さ０．２mmの仕上げ焼鈍が完了した一方向性珪素鋼板
（フォルステライト質の１次被膜あり）に片面４ｇ／ｍ2となるように塗布、乾
燥後、Ｈ2を５ vol％含有するＮ2雰囲気中で８００℃、５分間焼き付けることに
よって表面に酸化物被膜を形成した。
【００２２】
化学分析、Ｘ線回折、電子顕微鏡等の結果から、得られた被膜はＭｇＯ，α−
Ａｌ2Ｏ3，スピネルを主体としていることがわかった。２０mmφの円柱の周囲に
、その角度が１８０度となるように巻き付け試験を行い、その剥離状況から評価
した被膜の密着性はきわめて良好であった。片面の被膜を除去し、板の曲がりか
ら測定した鋼板への付与張力、および磁気特性を表１に記した。
表１の結果から、いずれも著しく鉄損の低い一方向性珪素鋼板が得られている
ことがわかる。また表面に形成された被膜の化学的安定性もきわめて良好であっ
た。
【００２３】
【表１】
【００２４】
実施例２
市販の酸化マグネシウム微粉末、ベーマイト粉末（平均粒径：１００nm）を表
２に示した割合に混合しこれに蒸留水を加えて混合ゾルを作製した。これをＳｉ
を３．２％含有し、酸化アルミニウムを焼鈍分離剤として塗布し、２次再結晶と
同時に鏡面化処理を施した厚さ０．２mmの一方向性珪素鋼板に片面４ｇ／ｍ2と
なるように塗布、乾燥後、Ｈ2を１０ vol％含有するＮ2雰囲気中で１０００℃、
１０分間焼き付けることによって表面に酸化物被膜を形成した。
【００２５】
化学分析、Ｘ線回折、電子顕微鏡等の結果から測定した被膜の結晶相を表２に
記した。表中の全ての組成において、スピネルの生成が確認された。実施例１と
同様に評価した被膜の密着性はきわめて良好であった。片面の被膜を除去し、板
の曲がりから測定した鋼板への付与張力、および磁気特性を表２に併記した。
表２の結果から、いずれも著しく鉄損の低い一方向性珪素鋼板が得られている
ことがわかる。また表面に形成された被膜の化学的安定性もきわめて良好であっ
た。
【００２６】
【表２】
【００２７】
実施例３
市販の酸化マグネシウム微粉末、ベーマイト粉末（平均粒径：１００nm）、テ
トラエトキシシラン、ほう酸試薬を表３に示した割合に混合し、これに蒸留水を
加えて混合ゾルを作製した。これを、Ｓｉを３．２％含有する厚さ０．２mmの仕
上げ焼鈍が完了した一方向性珪素鋼板（フォルステライト質の１次被膜あり）に
片面４ｇ／ｍ2となるように塗布、乾燥後、Ｈ2を３ vol％含有するＮ2雰囲気中
で８５０℃、３分間焼き付けることによって表面に酸化物被膜を形成した。
【００２８】
化学分析、Ｘ線回折、電子顕微鏡等の結果から測定した被膜の結晶相を表３に
記した。ほう素、珪素を含有する結晶質相が観察されないことより、ほう素、珪
素成分は非晶質相となって存在していることがわかる。実施例１と同様に評価し
た被膜の密着性はきわめて良好であった。片面の被膜を除去し、板の曲がりから
測定した鋼板への付与張力、および磁気特性を表３に併記した。
表３の結果から、いずれも著しく鉄損の低い一方向性珪素鋼板が得られている
ことがわかる。また表面に形成された被膜の化学的安定性もきわめて良好であっ
た。
【００２９】
【表３】
【００３０】
【発明の効果】
本発明により、特定成分の被膜を有し、化学的に安定で、かつその張力付与効
果によって鉄損が著しく改善された一方向性珪素鋼板を提供することができる。
本発明は特に、従来から用いられている１次被膜を有する鋼板、あるいは著し
い低鉄損化を目的とした鏡面化鋼板のいずれに対しても良好な特性を示し、汎用
性の観点からも工業的効果は甚大である。BACKGROUND OF THE INVENTION [0001] Field of the Invention The present invention is to have a coating that imparts a large tension to the steel sheet surface, about the grain oriented silicon steel sheet the iron loss is reduced. 2. Description of the Related Art A grain-oriented silicon steel sheet has a crystal structure with (110) and [001] as main orientations and is widely used as a magnetic iron core material. There is a demand for a material with small iron loss. As a means for reducing iron loss of a unidirectional silicon steel sheet, a method of irradiating a laser beam to a steel sheet surface after finish annealing to give local strain and thereby subdivide magnetic domains is disclosed in JP-A-58-26405. No. 6,086,045. Japanese Patent Application Laid-Open No. 62-86175 discloses a magnetic domain refining means which does not lose its effect even after performing stress relief annealing (stress relief annealing) after iron core processing. On the other hand, an iron alloy containing iron and silicon has a large crystal magnetic anisotropy. Therefore, when an external tension is applied, the magnetic domain is subdivided to reduce eddy current loss, which is a main element of iron loss. Can be. Therefore, it is effective to apply a tension to the steel sheet to reduce iron loss of a unidirectional silicon steel sheet containing 5% or less of silicon, and it is effective to apply a tension up to about 1.5 kgf / mm 2 to effectively reduce iron loss. It is known that loss can be reduced. This tension is usually provided by a coating formed on the surface. Conventionally, a unidirectional silicon steel sheet has a primary coating mainly composed of forsterite formed by a reaction between an oxide on the steel sheet surface and an annealing separator in a finish annealing step, and Japanese Patent Application Laid-Open No. 48-39338. A tension of about 1.0 kgf / mm 2 is given by a two-layer coating of a secondary coating formed by baking a coating liquid mainly composed of colloidal silica and phosphate disclosed in Japanese Patent Application Laid-Open Publication No. H10-163,086. . Therefore, in the case of these existing coatings, although there is room for improving iron loss by applying a larger tension, an increase in the applied tension by increasing the thickness of the coating is not preferable because it results in a decrease in the space factor. Further, as another method for improving iron loss of a grain-oriented silicon steel sheet, mirror finishing is performed by removing irregularities on the steel sheet surface after finish annealing and an internal oxide layer near the surface, and performing metal finishing on the surface. Japanese Patent Publication No. 52-24499 discloses a method of plating, and Japanese Patent Publication No. 56-4150 and Japanese Patent Application Laid-Open No.
JP-A-2017732, JP-B-63-54767, and JP-A-2-134
No. 88, for example. In these cases as well, the greater the tension applied to the steel sheet by the coating, the greater the effect of improving iron loss. For these reasons, there has been a demand for a coating film having excellent adhesion and being thin and capable of applying a large tension to a steel sheet. SUMMARY OF THE INVENTION The present invention solves these problems in the prior art, and has a coating that imparts a large tension to a steel sheet on its surface to reduce the iron loss of the unidirectional silicon. The purpose is to provide steel sheets. Means for Solving the Problems [0007] The present invention provides a magnesium oxide, comprising, on a surface after finish annealing, 10% by weight or more of each component of magnesium oxide and aluminum oxide in a weight ratio to the entire coating. Unidirectional silicon steel sheet with aluminum oxide-based composite coating, magnesium oxide-aluminum oxide-based composite coating containing crystalline spinel, unidirectional silicon steel sheet, magnesium oxide-aluminum oxide-amorphous oxidation on surface after finish annealing Grain-oriented silicon steel sheet, a magnesium oxide-aluminum oxide-amorphous oxide-based composite coating having a composite-based coating, comprising a crystalline spinel and / or at least one of silicon, boron and phosphorus. The gist is a unidirectional silicon steel sheet containing a crystalline phase. Hereinafter, the present invention will be described in detail. The grain-oriented silicon steel sheet of the present invention has a magnesium oxide-aluminum oxide-based composite coating on its surface. Conventionally, a coating material having a small thermal expansion coefficient has been selected for applying tension to a silicon steel sheet, and a stress generated during cooling due to a difference in thermal expansion coefficient from the steel sheet has been used. However, it has been pointed out that not only the coefficient of thermal expansion but also the Young's modulus of the coating material is a factor that affects the application of tension to the steel sheet. Although it is impossible to clearly define the role of the coating components of the present invention, the aluminum oxide component has a relatively large Young's modulus, and a large tension is applied to the steel sheet by combining magnesium oxide with the aluminum oxide component. I guess. [0009] Magnesium oxide is known only as a periclase as a crystal phase, but aluminum oxide has several crystal systems such as α-, γ-, δ-, and θ-, Is not necessarily the same in each crystal system. However, the aluminum oxide of the present invention may be any of these. In addition, each of the compounds does not necessarily need to be a crystal having good crystallinity, and may be an amorphous compound having poor crystallinity, or a compound that is a precursor of the crystal. [0010] In addition, in some cases, the inclusion of crystalline spinel in these films makes it possible to impart a higher tension. Spinel is a crystal represented by the chemical formula of MgO.Al 2 O 3 , and is presumed to have given a high tension to the steel sheet due to the above-mentioned properties of a low thermal expansion coefficient and a high Young's modulus. It is known that a spinel has a solid solution region on the alumina excess side with a 1: 1 composition as the center, but the crystalline spinel present in the coating of the present invention may be either a stoichiometric composition or a solid solution. It can be used without any problem. The proportions of magnesium oxide and aluminum oxide in the composite coating of the present invention can be set in a relatively wide range, and can be any proportion. However, in order to maximize the characteristics of the composite coating, it is preferable that each component is contained at least 5% by weight, preferably 10% or more based on the whole coating. In addition, the amount of the crystalline spinel can be any ratio, and by containing this compound as much as possible, it is possible to impart higher tension.However, since the surface properties of the coating tend to deteriorate, It is preferred to determine the optimal amount accordingly. The content of the crystalline spinel is preferably 90% or less, more preferably 80% or less by weight based on the whole coating film, and is usually selected from the range of about 5 to 75%. [0012] Another unidirectional silicon steel sheet surface of the present invention has a magnesium oxide-aluminum oxide-amorphous oxide-based composite coating. The role of the magnesium oxide and aluminum oxide components has already been described, but the role of the amorphous oxide component has no significant effect on the application of tension to the steel sheet, and the surface smoothness and adhesion to the base steel sheet It is speculated that the properties have been greatly improved. Among them, it has been found that an amorphous phase containing at least one of silicon, boron and phosphorus as a component has a remarkable effect. Particularly when a glassy substance is formed, a remarkably great effect can be obtained. The content of silicon, boron and phosphorus in the amorphous phase is at least 50% by weight, preferably 70% by weight, based on the total amount of the respective amorphous phases.
% Or more. The amorphous phase may contain a small amount of components other than silicon, boron, and phosphorus. Potential elements include Al and Mg
In addition to Fe as a constituent material of a base material, Ti, Mn, and S as primary coating components, Li,
Na, K, Ca, Sr, Ba, V, Cr, Ni, Co, Cu and other alkali metals, alkaline earth metals, transition metal elements, or Sn, Pb, Bi, Sb
And the like. The content of the entire amorphous phase is not particularly limited. However, if the content is too large, the tension is not sufficiently applied to the steel sheet. Therefore, the content of the amorphous phase is 90% or less, more preferably 70% or less, based on the entire coating. . If the amount is too small, a sufficiently smooth coating surface and good adhesion may not be obtained in some cases. Therefore, it is desirable that the content be 5% or more, more preferably 10% or more, by weight relative to the entire coating. When the coating on the surface of the unidirectional silicon steel sheet of the present invention is too thick, the space factor is reduced. Therefore, it is preferable that the coating be as thin as possible according to the purpose. It is. More preferably, it is 2% or less of the thickness of the steel sheet. From the viewpoint of imparting tension, if the thickness is extremely thin, a sufficient effect cannot be obtained, and the thickness is preferably 0.1 μm or more. Hereinafter, a method for suitably producing the grain-oriented silicon steel sheet of the present invention will be described. [0015] A suspension containing a magnesium oxide precursor compound and an aluminum oxide precursor compound is applied to the steel sheet surface that has been subjected to finish annealing, dried, and then baked at a temperature of 500 to 1350 ° C to form an oxide film. Is a manufacturing method. The steel sheet which has been subjected to the finish annealing here is: a steel sheet which has been subjected to finish annealing by a conventionally known method and has a forsterite-based primary film formed on its surface.
A steel sheet, in which the secondary coating and the accompanying oxide layer have been removed by immersion in an acid:
Steel sheet which has been subjected to flattening annealing in hydrogen, or a steel sheet which has been polished by chemical polishing, electrolytic polishing, etc .: Alumina powder which is inert to film formation, or a trace amount of chloride It refers to a steel sheet or the like to which a conventionally known annealing separator containing an additive has been applied and which has been subjected to finish annealing under conditions that do not produce a primary coating. The magnesium oxide precursor compound is a general term for compounds that become magnesium oxide after baking (heat treatment). In addition to magnesium oxide, magnesium hydroxide or various magnesium salts such as magnesium nitrate, magnesium chloride, etc. Point to. Aluminum oxide precursor compound after baking (heat treatment)
Is a general term for compounds that become aluminum oxide.
Includes aluminum oxide hydrate represented by Al 2 O 3 .nH 2 O such as boehmite, aluminum hydroxide, or various aluminum salts such as aluminum nitrate and aluminum chloride. These raw materials are dispersed in a dispersion medium to prepare a suspension (slurry). The dispersion medium is most preferably water from the viewpoints of workability, cost and the like, but an organic solvent or a mixture thereof can be used unless there is any particular problem in other steps. Certain of the raw materials may dissolve at the time the slurry is made, but this is no problem. The slurry thus obtained is applied to the surface of the unidirectional silicon steel sheet which has been subjected to finish annealing by a coater such as a roll coater, a dipping method, spraying, or electrophoresis, which is a conventionally known method. After drying, an oxide film is formed on the surface by baking at 500 to 1350 ° C. The atmosphere at the time of baking is preferably a reducing atmosphere such as an inert gas atmosphere such as nitrogen or a nitrogen-hydrogen mixed atmosphere. An atmosphere containing air or oxygen is not preferable because it may oxidize the steel sheet. There is no particular limitation on the dew point of the atmospheric gas. If the baking temperature is lower than 500 ° C., the applied precursor may not become an oxide, and the baking temperature is low, so that sufficient tension is not developed, which is not preferable. On the other hand, when the temperature exceeds 1350 ° C., it is not economical, although there is no particular inconvenience, and it is more preferably 1250 ° C. or less. In the above-mentioned slurry, a thin, uniform and well-adhesive coating film may be obtained by using a fine particle dispersion system called a sol as an aluminum oxide precursor. This is particularly remarkable when a non-metallic substance does not exist on the surface and a film is formed directly on the metal surface. In such a case, the fine particle dispersion sol described above,
Alternatively, a sol containing a soluble component is suitably used. When a sol solution is used as the coating solution, the above-mentioned boehmite sol and / or alumina sol are particularly preferably used as the aluminum oxide precursor compound from the viewpoint of workability and cost. When an aluminum oxide precursor sol is used as the aluminum oxide precursor compound, the magnesium oxide precursor compound may be an ultrafine magnesium oxide powder prepared by a gas phase method or the like, a fine powder prepared by a liquid phase method or the like. It is preferable to use those in a state of being dispersed and soluble magnesium salts, thereby realizing uniform mixing at an extremely microscopic level. Also in the use of the aluminum oxide precursor sol, it is possible to disperse it in a dispersion medium, particularly water, as in the case of the above-mentioned slurry, and use it. In order to obtain particularly good dispersibility, pH control of the coating solution by addition of an acid, an alkali or the like is a frequently used technique, and can be performed without any particular problem in the present invention. Also, there is no problem at all in adding a trace amount of a surfactant or the like for improving the applicability to the steel sheet. Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples. Example 1 Commercially available magnesium oxide fine powder and aluminum oxide powder (α-Al 2 O 3 ) were mixed in the proportions shown in Table 1, and distilled water was added thereto to prepare a slurry. . this,
A 0.2-mm-thick finish-annealed unidirectional silicon steel sheet (containing a forsterite-type primary coating) containing 3.2% of Si was applied to a surface of 4 g / m 2 on one side, dried, and dried. 800 ° C. 2 a in an N 2 atmosphere containing 5 vol%, to form an oxide film on the surface by baking for 5 minutes. From the results of chemical analysis, X-ray diffraction, electron microscopy, etc., the coating obtained was MgO, α-
It turned out that it is mainly composed of Al 2 O 3 and spinel. A winding test was performed around a 20 mmφ cylinder so that the angle was 180 degrees, and the adhesion of the coating evaluated from the peeling state was extremely good. The coating on one side was removed, and the applied tension to the steel sheet measured from the bending of the sheet and the magnetic properties are shown in Table 1. From the results shown in Table 1, it can be seen that unidirectional silicon steel sheets having remarkably low iron loss are obtained. The chemical stability of the film formed on the surface was also very good. [Table 1] Example 2 Commercially available magnesium oxide fine powder and boehmite powder (average particle diameter: 100 nm) were mixed in the proportions shown in Table 2, and distilled water was added thereto to prepare a mixed sol. This is Si
And an aluminum oxide is applied as an annealing separator, and is subjected to a secondary recrystallization and a mirror finishing simultaneously with a 0.2 mm thick unidirectional silicon steel sheet to be 4 g / m 2 on one side. And dried at 1000 ° C. in an N 2 atmosphere containing 10 vol% of H 2 .
An oxide film was formed on the surface by baking for 10 minutes. Table 2 shows the crystal phase of the coating film measured from the results of chemical analysis, X-ray diffraction, electron microscope and the like. In all the compositions in the table, formation of spinel was confirmed. The adhesion of the coating evaluated in the same manner as in Example 1 was extremely good. The coating on one side was removed, and the applied tension to the steel sheet measured from the bending of the sheet and the magnetic properties were also shown in Table 2. From the results shown in Table 2, it can be seen that unidirectional silicon steel sheets having significantly low iron loss were obtained. The chemical stability of the film formed on the surface was also very good. [Table 2] Example 3 Commercially available fine magnesium oxide powder, boehmite powder (average particle size: 100 nm), tetraethoxysilane, and boric acid reagent were mixed in the proportions shown in Table 3, and distilled water was added thereto to form a mixed sol. Produced. This was applied to a 0.2-mm-thick finish-annealed unidirectional silicon steel sheet (having a forsterite primary coating) containing 3.2% of Si so as to have a surface of 4 g / m 2 and dried. Thereafter, the film was baked at 850 ° C. for 3 minutes in an N 2 atmosphere containing 3 vol% of H 2 to form an oxide film on the surface. Table 3 shows the crystal phase of the coating film measured from the results of chemical analysis, X-ray diffraction, electron microscope and the like. The absence of the crystalline phase containing boron and silicon indicates that the boron and silicon components are present in an amorphous phase. The adhesion of the coating evaluated in the same manner as in Example 1 was extremely good. The coating on one side was removed, and the applied tension to the steel sheet and the magnetic properties measured from the bending of the sheet were also shown in Table 3. From the results shown in Table 3, it can be seen that unidirectional silicon steel sheets having significantly low iron loss were obtained. The chemical stability of the film formed on the surface was also very good. [Table 3] According to the present invention, it is possible to provide a unidirectional silicon steel sheet having a coating of a specific component, being chemically stable, and having significantly improved iron loss due to its tension imparting effect. . The present invention shows good properties especially for conventionally used steel sheets having a primary coating or mirror-finished steel sheets for the purpose of remarkably reducing iron loss. The effect is enormous.
Claims (1)
、酸化アルミニウムそれぞれの成分を被膜全体に対する重量割合で１０重量％以
上含有することを特徴とする、酸化マグネシウム−酸化アルミニウム系複合被膜
を有する低鉄損一方向性珪素鋼板。 【請求項２】 酸化マグネシウム−酸化アルミニウム系複合被膜が結晶質スピ
ネルを含有する請求項１に記載の低鉄損一方向性珪素鋼板。 【請求項３】 仕上げ焼鈍後の一方向性珪素鋼板の表面に酸化マグネシウム−
酸化アルミニウム−非晶質酸化物系複合被膜を有する低鉄損一方向性珪素鋼板。 【請求項４】 酸化マグネシウム−酸化アルミニウム−非晶質酸化物系複合被
膜が、結晶質スピネル、および／または珪素、ほう素、りんの少なくとも１種を
成分として含む非晶質相を含有する請求項３に記載の低鉄損一方向性珪素鋼板。Claims 1. The surface of a grain-oriented silicon steel sheet after finish annealing contains at least 10% by weight of each component of magnesium oxide and aluminum oxide in a weight ratio to the whole coating. Low iron loss unidirectional silicon steel sheet having a magnesium oxide-aluminum oxide based composite coating. 2. The low iron loss unidirectional silicon steel sheet according to claim 1, wherein the magnesium oxide-aluminum oxide composite coating contains a crystalline spinel. 3. The surface of a grain-oriented silicon steel sheet after finish annealing is coated with magnesium oxide.
A low iron loss unidirectional silicon steel sheet having an aluminum oxide-amorphous oxide composite coating. 4. The magnesium oxide-aluminum oxide-amorphous oxide-based composite coating contains a crystalline spinel and / or an amorphous phase containing at least one of silicon, boron and phosphorus as a component. Item 4. A low iron loss unidirectional silicon steel sheet according to item 3.
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