JP2004323948A - Electrocrystallization plating bath for forming magnetic film, and electrocrystallization plating method using the same - Google Patents
Electrocrystallization plating bath for forming magnetic film, and electrocrystallization plating method using the same Download PDFInfo
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- JP2004323948A JP2004323948A JP2003123228A JP2003123228A JP2004323948A JP 2004323948 A JP2004323948 A JP 2004323948A JP 2003123228 A JP2003123228 A JP 2003123228A JP 2003123228 A JP2003123228 A JP 2003123228A JP 2004323948 A JP2004323948 A JP 2004323948A
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- 238000007747 plating Methods 0.000 title claims abstract description 54
- 238000000034 method Methods 0.000 title claims description 19
- 238000007714 electro crystallization reaction Methods 0.000 title abstract 6
- 229910001252 Pd alloy Inorganic materials 0.000 claims abstract description 24
- 229910001260 Pt alloy Inorganic materials 0.000 claims abstract description 23
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 12
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 claims abstract description 10
- NGPGDYLVALNKEG-UHFFFAOYSA-N azanium;azane;2,3,4-trihydroxy-4-oxobutanoate Chemical compound [NH4+].[NH4+].[O-]C(=O)C(O)C(O)C([O-])=O NGPGDYLVALNKEG-UHFFFAOYSA-N 0.000 claims abstract description 9
- SURQXAFEQWPFPV-UHFFFAOYSA-L iron(2+) sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Fe+2].[O-]S([O-])(=O)=O SURQXAFEQWPFPV-UHFFFAOYSA-L 0.000 claims abstract description 8
- 239000007788 liquid Substances 0.000 claims abstract description 8
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 6
- SORXVYYPMXPIFD-UHFFFAOYSA-N iron palladium Chemical compound [Fe].[Pd] SORXVYYPMXPIFD-UHFFFAOYSA-N 0.000 claims abstract description 6
- OBACEDMBGYVZMP-UHFFFAOYSA-N iron platinum Chemical compound [Fe].[Fe].[Pt] OBACEDMBGYVZMP-UHFFFAOYSA-N 0.000 claims abstract description 6
- BZOVBIIWPDQIHF-UHFFFAOYSA-N 3-hydroxy-2-methylbenzenesulfonic acid Chemical compound CC1=C(O)C=CC=C1S(O)(=O)=O BZOVBIIWPDQIHF-UHFFFAOYSA-N 0.000 claims abstract description 5
- 239000002253 acid Substances 0.000 claims abstract description 5
- 235000019270 ammonium chloride Nutrition 0.000 claims abstract description 5
- PIBWKRNGBLPSSY-UHFFFAOYSA-L palladium(II) chloride Chemical compound Cl[Pd]Cl PIBWKRNGBLPSSY-UHFFFAOYSA-L 0.000 claims abstract description 5
- 238000004070 electrodeposition Methods 0.000 claims description 29
- QUPIGYNEMXNSHO-UHFFFAOYSA-J iron(4+) disulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Fe+4].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O QUPIGYNEMXNSHO-UHFFFAOYSA-J 0.000 claims description 2
- 239000010408 film Substances 0.000 description 83
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 37
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 26
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 23
- 229910052742 iron Inorganic materials 0.000 description 19
- 239000000203 mixture Substances 0.000 description 10
- 239000002244 precipitate Substances 0.000 description 10
- 239000013078 crystal Substances 0.000 description 9
- 229910045601 alloy Inorganic materials 0.000 description 8
- 239000000956 alloy Substances 0.000 description 8
- 229910052763 palladium Inorganic materials 0.000 description 8
- 229910052697 platinum Inorganic materials 0.000 description 7
- 238000005259 measurement Methods 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000006104 solid solution Substances 0.000 description 4
- 238000002441 X-ray diffraction Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000008139 complexing agent Substances 0.000 description 3
- 238000001771 vacuum deposition Methods 0.000 description 3
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 2
- 238000001255 X-ray photoelectron diffraction Methods 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 238000005185 salting out Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229910001285 shape-memory alloy Inorganic materials 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 235000002906 tartaric acid Nutrition 0.000 description 1
- 239000011975 tartaric acid Substances 0.000 description 1
Images
Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は、磁気記録媒体を構成する磁性膜の形成に関し、特に、鉄−白金合金（以下、Ｆｅ−Ｐｔ合金と略す場合もある）磁性膜及び、鉄−パラジウム合金（以下、Ｆｅ−Ｐｄ合金と略す場合もある）磁性膜を電析めっきにより形成する技術に関する。
【０００２】
【従来の技術】
近年、磁気記録媒体の製造においては、記録密度の高密度化のため、スパッタリング法や真空蒸着法のような乾式法によりディスク基板上に形成した磁性膜を記録層とする薄膜型の磁気記録媒体の研究開発が盛んに行われている。
【０００３】
この磁気記録媒体の磁性膜材料としては、Ｆｅを含む鉄系合金等が一般的に知られている。これらの磁性膜は高記録密度特性を有し、乾式法により形成した薄膜の記録層はその記録密度を飛躍的に向上させているのが現状である。
【０００４】
しかしながら、乾式法により磁性膜を形成する場合、大量生産性の観点からすると、十分に満足するものとはいえない。いわゆるブロードバンド化による大量情報通信技術の進展を考慮すると、今後、高密度の記録媒体は必須であり、より高密度記録媒体を大量且つ低コストで提供できる製造技術が必要となる。このようなことから、大量生産が可能となる電析めっきという湿式法による磁性膜製造技術が現在注目されている。
【０００５】
例えば、鉄系合金磁性膜では、Ｆｅ−Ｎｉ系合金磁性膜（特許文献１、２参照）のめっき浴が知られている。
【０００６】
【特許文献１】特開２００２−２４９８９４号公報
【特許文献２】特開２００１−２８４１５４号公報
【０００７】
【発明の解決する課題】
このようにＦｅ−Ｎｉ系合金は磁性特性に優れ、電析めっきにより磁性膜を形成する技術も存在するため、現在はＦｅ系合金磁性膜として多く利用さている。
【０００８】
【発明の解決する課題】
ところで、Ｆｅ系合金のなかにはＦｅ−Ｐｔ合金やＦｅ−Ｐｄ合金が磁性特性に優れるものとして知られている。Ｆｅ−Ｐｔ合金はＬ１０構造を有し、高い磁気異方性を持つことが知られており、微粒状態でも熱の影響が少ない磁性膜となることが期待されている。しかしながら、このＦｅ−Ｐｔ合金に関しては、本発明者らが知る限りにおいて、真空蒸着法やスパッタリング法などの乾式法にて膜形成が行われているのみで、電析めっきによりＦｅ−Ｐｔ合金磁性膜を形成する技術はない。
【０００９】
また、Ｆｅ−Ｐｄ合金は、ＦｅとＰｄの組成が１：１及び１：３の原子比組成の付近で、不規則ｆｃｃ（面心立方晶）とＬ１０及びＬ１２との相変態を示し、３０ａｔ％Ｐｄ付近の組成ではマルテンサイト変態を示すことがしられており、磁性特性を有する形状記憶合金として注目されている。しかしながら、このＦｅ−Ｐｄ合金に関しても、本発明者らが知る限りにおいて、真空蒸着法やアーク溶解法などの乾式法にて膜形成が行われているのみで、電析めっきによりＦｅ−Ｐｄ合金磁性膜を形成する技術はない。
【００１０】
本発明は、以上のような事情のもとになされたもので、磁気記録媒体を構成する磁性膜のバリエーションを増やし、大量、且つ低コストで磁性膜の形成が可能となるべく、新たな電析めっき浴、即ち、Ｆｅ−Ｐｔ合金磁性膜及びＦｅ−Ｐｄ合金磁性膜形成用の電析めっき液を提供する。
【００１１】
【課題を解決するための手段】
かかる課題を解決するため、本発明者らは、鉄系合金磁性膜材料として、Ｆｅ−Ｐｔ合金及びＦｅ−Ｐｄ合金について鋭意研究した結果、これら鉄系合金で磁性膜を形成できる新しい電析めっき浴を見出した。
【００１２】
まず、第一の本発明は、Ｆｅ−Ｐｔ合金磁性膜を形成するもので、硫酸鉄七水和物を１〜５０ｇ／Ｌと、塩化白金酸（ＩＶ）を２〜６０ｇ／Ｌと、酒石酸アンモニウムを０．５〜５０ｇ／Ｌと、アンモニアを５〜２５０ｇ／Ｌとを含有することを特徴とする鉄−白金合金の磁性膜形成用電析めっき浴である。そして、第二の本発明はＦｅ−Ｐｄ合金磁性膜を形成するもので、硫酸鉄七水和物を１〜５０ｇ／Ｌと、塩化パラジウムを０．２〜５０ｇ／Ｌと、酒石酸アンモニウムを０．５〜７０ｇ／Ｌと、塩化アンモニウムを０．５〜３０ｇ／Ｌと、クレゾールスルホン酸を０．１〜１０ｇ／Ｌを含有することを特徴とする鉄−パラジウム合金の磁性膜形成用電析めっき浴である。
【００１３】
以下、本発明に係る各電析めっき浴について説明する。まず、第一の発明であるＦｅ−Ｐｔ合金磁性膜については、硫酸鉄七水和物と、塩化白金酸（ＩＶ）と、酒石酸アンモニウムと、アンモニアとを含有する組成の電析めっき浴により形成することができる。
【００１４】
硫酸鉄七水和物は、１ｇ／Ｌ未満であると、析出物中の鉄の析出がしづらくなり、５０ｇ／Ｌを超えると鉄が沈殿しやすくなる傾向となる。塩化白金酸（ＩＶ）は、２ｇ／Ｌ未満であると、白金が析出しづらくなり、６０ｇ／Ｌを超えると、合金比率をコントロールしづらくなる傾向となる。
【００１５】
酒石酸アンモニウムは、鉄の錯化剤の役割をし、０．５ｇ／Ｌ未満であると、鉄が沈殿しやすくなり、６０ｇ／Ｌを超えると鉄が共析しづらくなる傾向となる。また、アンモニアは、白金の錯化剤の役割をし、５ｇ／Ｌ未満であると、白金が沈殿しやすくなり、２５０ｇ／Ｌを超えると白金が共析しづらくなる傾向となる。
【００１６】
本発明に係る鉄−白金合金の磁性膜形成用電析めっき浴により磁性膜を形成する場合、電流密度を１００〜１０００Ａ／ｍ２、液温３０〜８０℃でめっき処理を行うことが好ましい。電流密度が１００Ａ／ｍ２未満であると、析出物の外観が均一となり、１０００Ａ／ｍ２を超えると、析出物の外観が焼けた状態になる傾向となる。そして、液温が３０℃未満であると析出しなくなり、８０℃を超えるとアンモニアが揮発し、めっき液の安定性が悪くなる傾向となる。
【００１７】
本発明に係る鉄−白金合金の磁性膜形成用電析めっき浴により磁性膜を形成すると、得られる磁性膜は微細な結晶により構成されており、３４ａｔ％〜８１ａｔ％という白金の比率が高い場合にあってはｆｃｃの固溶体を形成するものである。
【００１８】
次に、第二の発明であるＦｅ−Ｐｄ合金磁性膜については、硫酸鉄七水和物と、塩化パラジウムと、酒石酸アンモニウムと、塩化アンモニウムと、クレーゾールスルホン酸とを含有する組成の電析めっき浴から形成することができる。
【００１９】
硫酸鉄七水和物は、１ｇ／Ｌ未満であると、析出物中の鉄が析出しづらくなり、５０ｇ／Ｌを超えると鉄が沈殿しやすくなる傾向となる。塩化パラジウムは、０．２ｇ／Ｌ未満であると、パラジウムが析出しづらく、不均一な析出物となる傾向があり、５０ｇ／Ｌを超えると、鉄が析出しなくなる傾向となる。
【００２０】
酒石酸アンモニウムは、鉄の錯化剤の役割をし、０．５ｇ／Ｌ未満であると、鉄が沈殿しやすくなり、７０ｇ／Ｌを超えると鉄が共析しづらくなる傾向となる。塩化アンモニウムは、電気電導塩の役割をし、０．５ｇ／Ｌ未満であると、電気伝導の能力が低下して析出物の外観が不均一となり、３０ｇ／Ｌを超えると、塩析を生じやすくなる傾向となる。クレーゾールスルホン酸は、光沢剤の役割をし、０．１ｇ／Ｌ未満であると、十分な光沢外観が得られず、１０ｇ／Ｌを超えると析出物の外観に曇りが発生する傾向となる。
【００２１】
本発明に係る鉄−パラジウム合金の磁性膜形成用電析めっき浴により磁性膜を形成する場合、電流密度を６０〜１２０Ａ／ｍ２、液温２０〜６０℃でめっき処理を行うことが好ましい。電流密度が６０Ａ／ｍ２未満であると、析出物の外観が不均一で且つ鉄の析出がしづらくなり、１２０Ａ／ｍ２を超えると、析出物の外観が不均一となるからである。そして、液温が２０℃未満であると全く析出しなくなり、６０℃を超えると鉄の析出がしづらくなる傾向となるからである。
【００２２】
本発明に係る鉄−パラジウム合金の磁性膜形成用電析めっき浴により磁性膜を形成すると、得られる磁性膜は微細な結晶により構成され、パラジウムの比率が高い場合（４８ａｔ％〜７７ａｔ％）にあってはｆｃｃの固溶体を形成するものである。
【００２３】
【発明の実施の形態】
以下に、本発明の好ましい実施形態について説明する。
【００２４】
第一実施形態：この第一実施形態では、Ｆｅ−Ｐｔ合金磁性膜を形成する場合を説明する。磁性膜の形成は、表１に示す組成のめっき浴を準備し、チタン製のメッシュコーティングがされたＰｔアノード電極と、Ｃｕカソード電極とを用いて電析めっきすることにより行った。めっき処理は、液温６０℃、電流密度を１０、２５、５０、７３、９０Ａ／ｍ２の５つの条件で行い、電析厚み０．２〜０．５μｍの磁性膜を形成した。また、電析中にめっき液の撹拌を行った。
【００２５】
【表１】
実施例１及び２のめっき浴において、５つの電流密度条件により得られたＦｅ−Ｐｔ合金磁性膜をそれぞれエネルギー分散型Ｘ線分光器（ＥＤＳ）により分析し、磁性膜のＰｔ比率（ａｔ％）を調べた。その結果を図１に示す。図１より、電流密度が大きくなると、磁性膜中でのＰｔの占める割合が増加していることが判明した。また、めっき浴中のＰｔ濃度が高いほど磁性膜中でのＰｔの占める割合が大きいことが確認された。この結果より、めっき浴の組成や電流密度を変化させることにより、組成の異なるＦｅ−Ｐｔ合金磁性膜（Ｐｔ３４．６〜８１．８ａｔ％）が得られることが判明した。
【００２７】
次に、本実施形態で得られたＦｅ−Ｐｔ合金磁性膜の化学結合状態をＸ線光電子回折法（ＸＰＳ）により調べた結果について説明する。この測定は、実施例１の電流密度１０Ａ／ｍ２（Ｐｔ５７．２ａｔ％、図１参照）で得られた膜により行った。その結果、膜中のＦｅ、Ｐｔは、ともに金属状態のものであることが判明した。
【００２８】
そして、本実施形態で得られたＦｅ−Ｐｔ合金磁性膜の結晶構造、結晶粒径をＸ線回折（ＸＲＤ）、透過電子顕微鏡（ＴＥＭ、倍率６０万倍）により調べた結果について説明する。この測定は、実施例２の電流密度１０Ａ／ｍ２（Ｐｔ３４．０ａｔ％、図１参照）、実施例１の電流密度１０Ａ／ｍ２（Ｐｔ５７．２ａｔ％、図１参照）、実施例１の電流密度５０Ａ／ｍ２（Ｐｔ７５．５ａｔ％、図１参照）で得られた３つの膜について行った。その結果、電析めっきにより得られたＦｅ−Ｐｔ合金磁性膜は、５ｎｍオーダーの非常に微細化した結晶であることが判明した。
【００２９】
さらに、本実施形態で得られたＦｅ−Ｐｔ合金磁性膜の磁気的性質を振動型磁気天秤（ＶＳＭ）により調査した結果について説明する。この測定は、実施例１の電流密度１０Ａ／ｍ２（Ｐｔ５７．２ａｔ％、図１参照）で得られた膜について行った。その結果、めっきしたままのサンプルでは、保持力は面方向で、わずか１０．３Ｏｅであった。これに対して、同じサンプルで、真空下（１０−５〜１０−６Ｐａ）４５０°、１時間のアニール処理をした磁性膜についてＸ線回折（ＸＲＤ）、透過電子顕微鏡（ＴＥＭ、倍率６０万倍）により観察したところ、磁性膜構造の規則化が規則ｆｃｔ構造であることが判明した。そして、その保持力は面垂直方向で５７２．８Ｏｅであった。
【００３０】
第二実施形態：この第二実施形態では、Ｆｅ−Ｐｄ合金磁性膜を形成する場合を説明する。磁性膜の形成は、表２に示す組成のめっき浴を準備し、白金製のメッシュコーティングがされたアノード電極と、Ｃｕカソード電極とを用いて電析めっきすることにより行った。めっき処理は、液温４０℃、電流密度を６０、７０、８０、９０、１００、１１０、１２０Ａ／ｍ２の７つの条件で行い、電析厚み０．２〜０．５μｍの磁性膜を形成した。また、電析中にめっき液の撹拌を行った。
【００３１】
【表２】
実施例３〜５のめっき浴において、７つの電流密度条件により得られた各Ｆｅ−Ｐｄ合金磁性膜をそれぞれエネルギー分散型Ｘ線分光器（ＥＤＳ）により分析し、磁性膜のＰｄ比率（ａｔ％）を調べた。その結果を図２に示す。図２より、電流密度が大きくなると、磁性膜中でのＰｄの占める割合が減少していることが判明した。また、めっき浴中のＰｄ濃度が高いほど磁性膜中でのＰｄの占める割合が増加することが確認された。この結果より、めっき浴の組成や電流密度を変化させることにより、組成の異なるＦｅ−Ｐｄ合金磁性膜（Ｐｄ８〜７７ａｔ％）が得られることが判明した。
【００３３】
次に、本実施形態で得られたＦｅ−Ｐｄ合金磁性膜の化学結合状態をＸ線光電子回折法（ＸＰＳ）により調べた結果について説明する。この測定は、実施例３の電流密度８０Ａ／ｍ２（Ｐｄ７７ａｔ％、図２参照）で得られた膜により行った。その結果、膜中のＦｅ、Ｐｄは、ともに金属状態のものであることが判明した。
【００３４】
そして、本実施形態で得られたＦｅ−Ｐｄ合金磁性膜の結晶構造、結晶粒径をＸ線回折（ＸＲＤ）、透過電子顕微鏡（ＴＥＭ、倍率６０万倍）により観察した結果について説明する。この観察は、実施例４の電流密度１１０Ａ／ｍ２（Ｐｄ１５ａｔ％、図２参照）、実施例５の電流密度９０Ａ／ｍ２（Ｐｄ４８ａｔ％、図２参照）、実施例３の電流密度８０Ａ／ｍ２（Ｐｄ７７ａｔ％、図２参照）で得られた３つの膜について行った。その結果、電析めっきにより得られたＦｅ−Ｐｄ合金磁性膜は、５ｎｍオーダーの非常に微細化した結晶で構成されており、膜中のＰｄ比率が高くなると結晶粒径が小さくなる傾向も判明した。また、Ｐｄが１５ａｔ％の低い比率の磁性膜ではｂｃｃ固溶体構造をしており、Ｐｄが４８ａｔ％、７７ａｔ％の高い比率の磁性膜ではｆｃｃ固溶体構造をしていることが判明した。
【００３５】
さらに、本実施形態で得られたＦｅ−Ｐｄ合金磁性膜の磁気的性質を振動型磁気天秤（ＶＳＭ）により調査した結果について説明する。この測定は、実施例４の電流密度９０Ａ／ｍ２（Ｐｄ５２ａｔ％、図２参照）で得られた膜について行った。その結果、５２ａｔ％Ｐｄである磁性膜では、面内方向に磁化容易軸を持つことが判った。
【００３６】
最後に、本実施形態で得られたＦｅ−Ｐｄ合金磁性膜の表面状態を操作電子顕微鏡（ＳＥＭ、傾斜角３０°倍率６５０００）により観察した結果について説明する。この観察は、実施例５の電流密度１２０Ａ／ｍ２（Ｐｄ８ａｔ％、図２参照）、実施例５の電流密度１１０Ａ／ｍ２（Ｐｄ２８ａｔ％、図２参照）、実施例５の電流密度８０Ａ／ｍ２（Ｐｄ５４ａｔ％、図２参照）、実施例５の電流密度６０Ａ／ｍ２（Ｐｄ７７ａｔ％、図２参照）で得られた４つの膜について行った。その結果、Ｐｄ８ａｔ％、Ｐｄ２８ａｔ％の磁性膜については、若干の起伏が見られるものの、表面状態は非常に滑らかであることが判った。
【００３７】
【発明の効果】
以上説明したように、本発明の磁性膜形成用電析めっき浴によれば、Ｆｅ−Ｐｔ合金磁性膜及びＦｅ−Ｐｄ合金磁性膜を形成することができ、磁気記録媒体を構成する磁性膜のバリエーションを増やし、大量、且つ低コストで磁性膜の形成が可能となる。
【図面の簡単な説明】
【図１】第一実施形態の電流密度とＰｔ比率の関係を示すグラフ。
【図２】第二実施形態の電流密度とＰｄ比率の関係を示すグラフ。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to the formation of a magnetic film constituting a magnetic recording medium, and more particularly, to an iron-platinum alloy (hereinafter sometimes abbreviated to Fe-Pt alloy) magnetic film and an iron-palladium alloy (hereinafter Fe-Pd alloy). (Sometimes abbreviated as "abbreviated").
[0002]
[Prior art]
In recent years, in the production of magnetic recording media, in order to increase the recording density, a thin film type magnetic recording medium in which a magnetic film formed on a disk substrate by a dry method such as a sputtering method or a vacuum evaporation method is used as a recording layer. R & D is actively conducted.
[0003]
As a magnetic film material of this magnetic recording medium, an iron-based alloy containing Fe or the like is generally known. At present, these magnetic films have high recording density characteristics, and the recording layer of a thin film formed by a dry method has dramatically improved the recording density.
[0004]
However, when a magnetic film is formed by a dry method, it cannot be said that it is sufficiently satisfactory from the viewpoint of mass productivity. In view of the progress of mass information communication technology due to the so-called broadband technology, a high-density recording medium is indispensable in the future, and a manufacturing technology capable of providing a higher-density recording medium in a large amount at low cost is required. For this reason, a magnetic film manufacturing technique by a wet method called electrodeposition plating, which enables mass production, has attracted attention at present.
[0005]
For example, as an iron-based alloy magnetic film, a plating bath for an Fe-Ni-based alloy magnetic film (see
[0006]
[Patent Document 1] JP-A-2002-249894 [Patent Document 2] JP-A-2001-284154
[Problems to be solved by the invention]
As described above, Fe-Ni-based alloys have excellent magnetic properties, and there is also a technique for forming a magnetic film by electrodeposition plating.
[0008]
[Problems to be solved by the invention]
By the way, among Fe-based alloys, Fe-Pt alloy and Fe-Pd alloy are known as having excellent magnetic properties. Fe-Pt alloys have an L1 0 structure, it is known to have a high magnetic anisotropy, the influence of heat in fine condition that is less magnetic film is expected. However, regarding the Fe-Pt alloy, as far as the present inventors know, the film is formed only by a dry method such as a vacuum evaporation method or a sputtering method. There is no technology for forming a film.
[0009]
Further, Fe-Pd alloy, the composition of Fe and Pd is 1: 1 and 1: in the vicinity of the third atomic ratio, shows a phase transformation irregular fcc and (face-centered cubic) and L1 0 and L1 2 , 30 at% Pd, it is known that the composition exhibits martensitic transformation, and is attracting attention as a shape memory alloy having magnetic properties. However, as far as the present inventors know, as far as the present inventors know, the film is formed only by a dry method such as a vacuum deposition method or an arc melting method, and the Fe-Pd alloy is formed by electrodeposition plating. There is no technique for forming a magnetic film.
[0010]
The present invention has been made under the above circumstances, and a new deposition method has been developed to increase the variations of the magnetic film constituting the magnetic recording medium and to form the magnetic film at a large amount and at low cost. Provided is a plating bath, that is, an electrodeposition plating solution for forming an Fe—Pt alloy magnetic film and an Fe—Pd alloy magnetic film.
[0011]
[Means for Solving the Problems]
In order to solve this problem, the present inventors have conducted intensive studies on Fe-Pt alloys and Fe-Pd alloys as iron-based alloy magnetic film materials. As a result, a new electrodeposition plating method capable of forming a magnetic film with these iron-based alloys has been conducted. I found a bath.
[0012]
First, the first invention forms an Fe—Pt alloy magnetic film, and contains 1 to 50 g / L of iron sulfate heptahydrate, 2 to 60 g / L of chloroplatinic acid (IV), and tartaric acid. An electrodeposition plating bath for forming a magnetic film of an iron-platinum alloy, comprising 0.5 to 50 g / L of ammonium and 5 to 250 g / L of ammonia. The second invention forms a Fe-Pd alloy magnetic film, and contains 1 to 50 g / L of iron sulfate heptahydrate, 0.2 to 50 g / L of palladium chloride, and 0 to 50 g / L of ammonium tartrate. 0.5 to 70 g / L, 0.5 to 30 g / L of ammonium chloride, and 0.1 to 10 g / L of cresol sulfonic acid, for depositing an iron-palladium alloy for forming a magnetic film. It is a plating bath.
[0013]
Hereinafter, each electrodeposition plating bath according to the present invention will be described. First, the Fe—Pt alloy magnetic film of the first invention is formed by an electrodeposition plating bath having a composition containing iron sulfate heptahydrate, chloroplatinic acid (IV), ammonium tartrate, and ammonia. can do.
[0014]
If the iron sulfate heptahydrate is less than 1 g / L, precipitation of iron in the precipitate becomes difficult, and if it exceeds 50 g / L, iron tends to precipitate. If the amount of chloroplatinic acid (IV) is less than 2 g / L, it is difficult to deposit platinum, and if it exceeds 60 g / L, the alloy ratio tends to be difficult to control.
[0015]
Ammonium tartrate acts as a complexing agent for iron, and if it is less than 0.5 g / L, iron tends to precipitate, and if it exceeds 60 g / L, it tends to be difficult for eutectoid. Ammonia serves as a complexing agent for platinum. When the amount is less than 5 g / L, platinum is likely to precipitate, and when it exceeds 250 g / L, platinum tends to be difficult to eutectoid.
[0016]
When a magnetic film is formed by the electrodeposition plating bath for forming a magnetic film of an iron-platinum alloy according to the present invention, it is preferable to perform plating at a current density of 100 to 1000 A / m 2 and a liquid temperature of 30 to 80 ° C. When the current density is less than 100 A / m 2 , the appearance of the precipitate becomes uniform, and when the current density exceeds 1000 A / m 2 , the appearance of the precipitate tends to be burnt. If the solution temperature is lower than 30 ° C., no precipitation occurs, and if it exceeds 80 ° C., ammonia evaporates and the stability of the plating solution tends to deteriorate.
[0017]
When a magnetic film is formed by the electrodeposition plating bath for forming a magnetic film of an iron-platinum alloy according to the present invention, the obtained magnetic film is composed of fine crystals and has a high platinum ratio of 34 at% to 81 at%. Is to form a solid solution of fcc.
[0018]
Next, regarding the Fe—Pd alloy magnetic film of the second invention, electrodeposition of a composition containing iron sulfate sulfate heptahydrate, palladium chloride, ammonium tartrate, ammonium chloride, and cresol sulfonic acid. It can be formed from a plating bath.
[0019]
When the amount of iron sulfate heptahydrate is less than 1 g / L, iron in the precipitate becomes difficult to precipitate, and when it exceeds 50 g / L, iron tends to precipitate. If the amount of palladium chloride is less than 0.2 g / L, palladium tends to hardly precipitate and tends to be a non-uniform precipitate. If the amount exceeds 50 g / L, iron does not tend to precipitate.
[0020]
Ammonium tartrate acts as a complexing agent for iron, and if it is less than 0.5 g / L, iron tends to precipitate, and if it exceeds 70 g / L, iron tends to be difficult to eutectoid. Ammonium chloride plays the role of an electrically conductive salt. When the amount is less than 0.5 g / L, the ability of electric conduction is reduced and the appearance of the precipitate becomes uneven. When the amount exceeds 30 g / L, salting out occurs. It tends to be easier. Cresol sulfonic acid acts as a brightener, and if it is less than 0.1 g / L, sufficient gloss appearance cannot be obtained, and if it exceeds 10 g / L, the appearance of the precipitate tends to be cloudy. .
[0021]
When a magnetic film is formed by the iron-palladium alloy electrodepositing plating bath for forming a magnetic film according to the present invention, it is preferable to perform plating at a current density of 60 to 120 A / m 2 and a liquid temperature of 20 to 60 ° C. If the current density is less than 60 A / m 2 , the appearance of the precipitate is uneven and the precipitation of iron is difficult, and if it exceeds 120 A / m 2 , the appearance of the precipitate is uneven. If the liquid temperature is lower than 20 ° C., no precipitation occurs, and if the liquid temperature exceeds 60 ° C., the precipitation of iron tends to be difficult.
[0022]
When a magnetic film is formed by the electrodeposition plating bath for forming a magnetic film of an iron-palladium alloy according to the present invention, the obtained magnetic film is composed of fine crystals, and when the ratio of palladium is high (48 at% to 77 at%). In this case, a fcc solid solution is formed.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
[0024]
First Embodiment : In the first embodiment, a case where an Fe—Pt alloy magnetic film is formed will be described. The formation of the magnetic film was performed by preparing a plating bath having the composition shown in Table 1, and performing electrodeposition plating using a Pt anode electrode coated with titanium mesh and a Cu cathode electrode. The plating treatment was performed under five conditions of a liquid temperature of 60 ° C. and current densities of 10, 25, 50, 73, and 90 A / m 2 , to form a magnetic film having an electrodeposition thickness of 0.2 to 0.5 μm. Further, the plating solution was stirred during the electrodeposition.
[0025]
[Table 1]
In the plating baths of Examples 1 and 2, the Fe—Pt alloy magnetic films obtained under the five current density conditions were respectively analyzed by an energy dispersive X-ray spectrometer (EDS), and the Pt ratio (at%) of the magnetic films was measured. Was examined. The result is shown in FIG. From FIG. 1, it was found that as the current density increased, the proportion of Pt in the magnetic film increased. It was also confirmed that the higher the Pt concentration in the plating bath, the greater the proportion of Pt in the magnetic film. From these results, it was found that Fe--Pt alloy magnetic films (Pt 34.6 to 81.8 at%) having different compositions can be obtained by changing the composition of the plating bath and the current density.
[0027]
Next, the result of examining the chemical bonding state of the Fe—Pt alloy magnetic film obtained in the present embodiment by X-ray photoelectron diffraction (XPS) will be described. This measurement was performed on the film obtained in Example 1 at a current density of 10 A / m 2 (Pt: 57.2 at%, see FIG. 1). As a result, it was found that both Fe and Pt in the film were in a metal state.
[0028]
Then, the results of examining the crystal structure and crystal grain size of the Fe—Pt alloy magnetic film obtained in this embodiment by X-ray diffraction (XRD) and transmission electron microscope (TEM, magnification: 600,000) will be described. This measurement, a current density of 10A /
[0029]
Further, the results of investigating the magnetic properties of the Fe—Pt alloy magnetic film obtained in this embodiment using a vibration type magnetic balance (VSM) will be described. This measurement was performed on the film obtained in Example 1 at a current density of 10 A / m 2 (Pt: 57.2 at%, see FIG. 1). As a result, in the as-plated sample, the holding force was only 10.3 Oe in the plane direction. On the other hand, the same sample was annealed at 450 ° C. for 1 hour under vacuum (10 −5 to 10 −6 Pa), and the magnetic film was subjected to X-ray diffraction (XRD), transmission electron microscope (TEM, magnification: 600,000). Observation), it was found that the regularization of the magnetic film structure was a regular fct structure. The holding force was 572.8 Oe in the direction perpendicular to the surface.
[0030]
Second Embodiment In the second embodiment, a case where a Fe—Pd alloy magnetic film is formed will be described. The formation of the magnetic film was performed by preparing a plating bath having the composition shown in Table 2 and performing electrodeposition plating using an anode electrode coated with platinum mesh and a Cu cathode electrode. The plating process is performed under seven conditions of a liquid temperature of 40 ° C. and current densities of 60, 70, 80, 90, 100, 110, and 120 A / m 2 to form a magnetic film having an electrodeposition thickness of 0.2 to 0.5 μm. did. Further, the plating solution was stirred during the electrodeposition.
[0031]
[Table 2]
In the plating baths of Examples 3 to 5, each Fe—Pd alloy magnetic film obtained under the seven current density conditions was analyzed by an energy dispersive X-ray spectrometer (EDS), and the Pd ratio (at%) of the magnetic film was analyzed. ). The result is shown in FIG. From FIG. 2, it was found that as the current density increased, the proportion of Pd in the magnetic film decreased. It was also confirmed that the higher the Pd concentration in the plating bath, the higher the proportion of Pd in the magnetic film. From this result, it was found that by changing the composition and current density of the plating bath, Fe—Pd alloy magnetic films (
[0033]
Next, the result of examining the chemical bonding state of the Fe—Pd alloy magnetic film obtained in the present embodiment by X-ray photoelectron diffraction (XPS) will be described. This measurement was performed on the film obtained in Example 3 at a current density of 80 A / m 2 (Pd 77 at%, see FIG. 2). As a result, it was found that both Fe and Pd in the film were in a metal state.
[0034]
The crystal structure and crystal grain size of the Fe—Pd alloy magnetic film obtained in the present embodiment will be described with reference to the results of observation by X-ray diffraction (XRD) and transmission electron microscope (TEM, magnification: 600,000 times). This observation was made by observing the current density of 110 A / m 2 (Pd 15 at%, see FIG. 2) of Example 4, the current density of 90 A / m 2 of Example 5 (Pd 48 at%, see FIG. 2), and the current density of 80 A / m 2 of Example 3. This was performed on three films obtained with m 2 (Pd 77 at%, see FIG. 2). As a result, the Fe-Pd alloy magnetic film obtained by electrodeposition plating was composed of very fine crystals of the order of 5 nm, and it was found that the crystal grain size tended to decrease as the Pd ratio in the film increased. did. It was also found that a magnetic film having a low Pd content of 15 at% had a bcc solid solution structure, and a magnetic film having a high Pd content of 48 at% and 77 at% had an fcc solid solution structure.
[0035]
Further, the results of investigating the magnetic properties of the Fe—Pd alloy magnetic film obtained in this embodiment using a vibration type magnetic balance (VSM) will be described. This measurement was performed on the film obtained in Example 4 at a current density of 90 A / m 2 (Pd: 52 at%, see FIG. 2). As a result, it was found that the magnetic film of 52 at% Pd had an easy axis of magnetization in the in-plane direction.
[0036]
Finally, the result of observing the surface state of the Fe—Pd alloy magnetic film obtained in the present embodiment with an operation electron microscope (SEM,
[0037]
【The invention's effect】
As described above, according to the electrodeposition plating bath for forming a magnetic film of the present invention, the Fe—Pt alloy magnetic film and the Fe—Pd alloy magnetic film can be formed, and the magnetic film constituting the magnetic recording medium can be formed. The number of variations can be increased, and a magnetic film can be formed in large quantities at low cost.
[Brief description of the drawings]
FIG. 1 is a graph showing a relationship between a current density and a Pt ratio according to the first embodiment.
FIG. 2 is a graph showing a relationship between a current density and a Pd ratio according to the second embodiment.
Claims (4)
電流密度１００〜１０００Ａ／ｍ２、液温３０〜８０℃でめっき処理を行う電析めっき方法。An electrodeposition plating method for performing a plating process for forming a magnetic film using the electrodeposition plating bath for forming a magnetic film according to claim 1,
An electrodeposition plating method in which plating is performed at a current density of 100 to 1000 A / m 2 and a liquid temperature of 30 to 80 ° C.
電流密度６０〜１２０Ａ／ｍ２、液温２０〜６０でめっき処理を行う電析めっき方法。An electrodeposition plating method for performing a plating treatment for forming a magnetic film using the electrodeposition plating bath for forming a magnetic film according to claim 3,
An electrodeposition plating method for performing plating at a current density of 60 to 120 A / m 2 and a solution temperature of 20 to 60.
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| WO2005068688A2 (en) * | 2004-01-16 | 2005-07-28 | Canon Kabushiki Kaisha | Plating solution, process for producing a structure with the plating solution, and apparatus employing the plating solution |
| JP2007154285A (en) * | 2005-12-07 | 2007-06-21 | Electroplating Eng Of Japan Co | Method for producing magnetic film of cobalt-platinum alloy |
| JP2011063842A (en) * | 2009-09-16 | 2011-03-31 | Shinshu Univ | METHOD FOR PLATING ARTICLE WITH Fe-Pt ALLOY AND LIQUID FOR PLATING ARTICLE WITH Fe-Pt ALLOY |
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- 2003-04-28 JP JP2003123228A patent/JP2004323948A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005068688A2 (en) * | 2004-01-16 | 2005-07-28 | Canon Kabushiki Kaisha | Plating solution, process for producing a structure with the plating solution, and apparatus employing the plating solution |
| WO2005068688A3 (en) * | 2004-01-16 | 2006-03-02 | Canon Kk | Plating solution, process for producing a structure with the plating solution, and apparatus employing the plating solution |
| US7641783B2 (en) | 2004-01-16 | 2010-01-05 | Canon Kabushiki Kaisha | Plating solution, process for producing a structure with the plating solution, and apparatus employing the plating solution |
| JP2007154285A (en) * | 2005-12-07 | 2007-06-21 | Electroplating Eng Of Japan Co | Method for producing magnetic film of cobalt-platinum alloy |
| JP2011063842A (en) * | 2009-09-16 | 2011-03-31 | Shinshu Univ | METHOD FOR PLATING ARTICLE WITH Fe-Pt ALLOY AND LIQUID FOR PLATING ARTICLE WITH Fe-Pt ALLOY |
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