JPH0321638B2 - - Google Patents
Info
- Publication number
- JPH0321638B2 JPH0321638B2 JP19890787A JP19890787A JPH0321638B2 JP H0321638 B2 JPH0321638 B2 JP H0321638B2 JP 19890787 A JP19890787 A JP 19890787A JP 19890787 A JP19890787 A JP 19890787A JP H0321638 B2 JPH0321638 B2 JP H0321638B2
- Authority
- JP
- Japan
- Prior art keywords
- silver
- tin
- acid
- plating
- salt
- 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
Links
- 238000007747 plating Methods 0.000 claims description 51
- 239000002253 acid Substances 0.000 claims description 31
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical class [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 25
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 19
- 229910052709 silver Inorganic materials 0.000 claims description 19
- 239000004332 silver Substances 0.000 claims description 19
- 150000003839 salts Chemical class 0.000 claims description 14
- 229910001128 Sn alloy Inorganic materials 0.000 claims description 13
- KXZJHVJKXJLBKO-UHFFFAOYSA-N chembl1408157 Chemical compound N=1C2=CC=CC=C2C(C(=O)O)=CC=1C1=CC=C(O)C=C1 KXZJHVJKXJLBKO-UHFFFAOYSA-N 0.000 claims description 7
- NNFCIKHAZHQZJG-UHFFFAOYSA-N potassium cyanide Chemical compound [K+].N#[C-] NNFCIKHAZHQZJG-UHFFFAOYSA-N 0.000 claims description 7
- 229910021626 Tin(II) chloride Inorganic materials 0.000 claims description 6
- 229940100890 silver compound Drugs 0.000 claims description 4
- 150000003379 silver compounds Chemical class 0.000 claims description 4
- 150000005846 sugar alcohols Chemical class 0.000 claims description 4
- 239000007864 aqueous solution Substances 0.000 claims description 2
- QCEUXSAXTBNJGO-UHFFFAOYSA-N [Ag].[Sn] Chemical compound [Ag].[Sn] QCEUXSAXTBNJGO-UHFFFAOYSA-N 0.000 description 11
- 239000008139 complexing agent Substances 0.000 description 9
- -1 silver cyanide compound Chemical class 0.000 description 7
- 238000002845 discoloration Methods 0.000 description 6
- 238000001556 precipitation Methods 0.000 description 4
- 229940098221 silver cyanide Drugs 0.000 description 4
- GGCZERPQGJTIQP-UHFFFAOYSA-N sodium;9,10-dioxoanthracene-2-sulfonic acid Chemical compound [Na+].C1=CC=C2C(=O)C3=CC(S(=O)(=O)O)=CC=C3C(=O)C2=C1 GGCZERPQGJTIQP-UHFFFAOYSA-N 0.000 description 4
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 3
- 229910001432 tin ion Inorganic materials 0.000 description 3
- GEZAUFNYMZVOFV-UHFFFAOYSA-J 2-[(2-oxo-1,3,2$l^{5},4$l^{2}-dioxaphosphastannetan-2-yl)oxy]-1,3,2$l^{5},4$l^{2}-dioxaphosphastannetane 2-oxide Chemical compound [Sn+2].[Sn+2].[O-]P([O-])(=O)OP([O-])([O-])=O GEZAUFNYMZVOFV-UHFFFAOYSA-J 0.000 description 2
- RGHNJXZEOKUKBD-SQOUGZDYSA-N D-gluconic acid Chemical compound OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C(O)=O RGHNJXZEOKUKBD-SQOUGZDYSA-N 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 150000003863 ammonium salts Chemical class 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- XPPKVPWEQAFLFU-UHFFFAOYSA-N diphosphoric acid Chemical compound OP(O)(=O)OP(O)(O)=O XPPKVPWEQAFLFU-UHFFFAOYSA-N 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- 150000002825 nitriles Chemical class 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- 229940005657 pyrophosphoric acid Drugs 0.000 description 2
- LFAGQMCIGQNPJG-UHFFFAOYSA-N silver cyanide Chemical compound [Ag+].N#[C-] LFAGQMCIGQNPJG-UHFFFAOYSA-N 0.000 description 2
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 2
- 229910052708 sodium Inorganic materials 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 229940071182 stannate Drugs 0.000 description 2
- 125000005402 stannate group Chemical group 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 229910001369 Brass Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- FBPFZTCFMRRESA-KVTDHHQDSA-N D-Mannitol Chemical compound OC[C@@H](O)[C@@H](O)[C@H](O)[C@H](O)CO FBPFZTCFMRRESA-KVTDHHQDSA-N 0.000 description 1
- RGHNJXZEOKUKBD-AIHAYLRMSA-N D-altronic acid Chemical compound OC[C@@H](O)[C@@H](O)[C@@H](O)[C@H](O)C(O)=O RGHNJXZEOKUKBD-AIHAYLRMSA-N 0.000 description 1
- RGHNJXZEOKUKBD-UHFFFAOYSA-N D-gluconic acid Natural products OCC(O)C(O)C(O)C(O)C(O)=O RGHNJXZEOKUKBD-UHFFFAOYSA-N 0.000 description 1
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 1
- 241000360590 Erythrites Species 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- FOIXSVOLVBLSDH-UHFFFAOYSA-N Silver ion Chemical compound [Ag+] FOIXSVOLVBLSDH-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000010951 brass Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- UNXHWFMMPAWVPI-ZXZARUISSA-N erythritol Chemical compound OC[C@H](O)[C@H](O)CO UNXHWFMMPAWVPI-ZXZARUISSA-N 0.000 description 1
- 239000000174 gluconic acid Substances 0.000 description 1
- 235000012208 gluconic acid Nutrition 0.000 description 1
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000010907 mechanical stirring Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- LNOPIUAQISRISI-UHFFFAOYSA-N n'-hydroxy-2-propan-2-ylsulfonylethanimidamide Chemical compound CC(C)S(=O)(=O)CC(N)=NO LNOPIUAQISRISI-UHFFFAOYSA-N 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 229940044652 phenolsulfonate Drugs 0.000 description 1
- HKSGQTYSSZOJOA-UHFFFAOYSA-N potassium argentocyanide Chemical compound [K+].[Ag+].N#[C-].N#[C-] HKSGQTYSSZOJOA-UHFFFAOYSA-N 0.000 description 1
- WSHYKIAQCMIPTB-UHFFFAOYSA-M potassium;2-oxo-3-(3-oxo-1-phenylbutyl)chromen-4-olate Chemical compound [K+].[O-]C=1C2=CC=CC=C2OC(=O)C=1C(CC(=O)C)C1=CC=CC=C1 WSHYKIAQCMIPTB-UHFFFAOYSA-M 0.000 description 1
- CQLFBEKRDQMJLZ-UHFFFAOYSA-M silver acetate Chemical compound [Ag+].CC([O-])=O CQLFBEKRDQMJLZ-UHFFFAOYSA-M 0.000 description 1
- 229940071536 silver acetate Drugs 0.000 description 1
- 229910001961 silver nitrate Inorganic materials 0.000 description 1
- XNGYKPINNDWGGF-UHFFFAOYSA-L silver oxalate Chemical compound [Ag+].[Ag+].[O-]C(=O)C([O-])=O XNGYKPINNDWGGF-UHFFFAOYSA-L 0.000 description 1
- YPNVIBVEFVRZPJ-UHFFFAOYSA-L silver sulfate Chemical compound [Ag+].[Ag+].[O-]S([O-])(=O)=O YPNVIBVEFVRZPJ-UHFFFAOYSA-L 0.000 description 1
- 229910000367 silver sulfate Inorganic materials 0.000 description 1
- IYAGECKNKFUYAJ-UHFFFAOYSA-N silver;sodium;dicyanide Chemical compound [Na+].[Ag+].N#[C-].N#[C-] IYAGECKNKFUYAJ-UHFFFAOYSA-N 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- 150000003606 tin compounds Chemical class 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
- FAKFSJNVVCGEEI-UHFFFAOYSA-J tin(4+);disulfate Chemical compound [Sn+4].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O FAKFSJNVVCGEEI-UHFFFAOYSA-J 0.000 description 1
- HPGGPRDJHPYFRM-UHFFFAOYSA-J tin(iv) chloride Chemical compound Cl[Sn](Cl)(Cl)Cl HPGGPRDJHPYFRM-UHFFFAOYSA-J 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- HEBKCHPVOIAQTA-SCDXWVJYSA-N xylitol Chemical compound OC[C@H](O)[C@@H](O)[C@H](O)CO HEBKCHPVOIAQTA-SCDXWVJYSA-N 0.000 description 1
Landscapes
- Electroplating And Plating Baths Therefor (AREA)
Description
産業上の利用分野
本発明は、銀−錫合金めつき浴に関する。
従来の技術及びその問題点
銀は、電気抵抗が金属中で最も小さく、良好な
ハンダ付け性を有するため、電気工業、電気工業
等の分野では、銀めつきとして広く使用されてい
る。しかしながら、銀は大気中で硫化物の生成に
よつて変色しやすいという欠点があり、通常、銀
めつきを行なつた後、変色防止のための後処理を
行なうことが必要とされている。
一方、冶金学的には、銀に錫を添加した銀−錫
合金は、銀の優れた性質を有し、かつ耐変色性に
優れた合金であることが知られている。
従来銀−錫合金めつき浴としては、銀シアン化
合物と錫酸塩とを基本成分とするめつき浴、銀シ
アン化合物とピロリン酸錫錯塩とを基本成分とす
るめつき浴等が知られており、これらのめつき浴
から得られる銀−錫合金皮膜も優れた耐変色性を
有することが確認されている。
この様な、銀成分として銀シアン化合物を用い
るめつき浴では、銀の還元析出をさけるために遊
離のシアン化カリウム、シアン化ナトリウム等を
めつき浴中に多量に存在させることが必要であ
り、この様なシアン化合物を多量に使用するめつ
き液は通常PH11以上の高PH状態となる。ところ
が、この様な高PHのめつき浴では、錫成分とし
て、錫酸塩を用いる場合には、錫イオンが４価の
イオンとなり、めつき皮膜中に析出し難くなる。
このため浴中の銀イオン濃度を極端に低く押さえ
て、錫イオンの比率を非常に高くしなければ銀−
錫合金めつき皮膜を得ることができない。しかし
ながら、銀イオンと錫イオンとに極端な濃度差が
あると、めつき浴の管理が難しく、一定比率の合
金皮膜を安定に析出させることが困難となり、め
つき浴としては実用的ではない。
一方、ピロリン酸を錫の錯化剤として用いるめ
つき浴では、ピロリン酸と錫とはPH８〜10程度で
安定な錯体を形成するので、PH11以上の高PH状態
では、錯塩の安定性が悪く、二酸化錫の沈澱が生
じ易くなる。
更に、上記したいずれのめつき浴も、良好なめ
つき皮膜が得られる電流密度範囲が非常に狭いと
いう欠点もある。
問題点を解決するための手段
本発明者は、上記した如き現状に鑑みて、安定
性が高く、かつ広範囲の電流密度で良好なめつき
皮膜を形成し得る銀−錫合金めつき浴を得るべく
鋭意研究を重ねてきた。その結果、糖酸又はその
塩、アルドン酸又はその塩、及び糖アルコールか
ら選ばれた少なくとも１種の化合物を錫の錯化剤
として用いる場合には、PH11以上という高PH状態
でも安定な錫錯塩が形成され、このためシアン化
カリウム、シアン化ナトリウム等の銀化合物の錯
化剤を多量に添加した高PHのめつき浴において
も、錫化合物を安定な錯塩として存在させること
が可能となり、しかもこの様な錯化剤を用いて得
られためつき浴は、広範囲の電流密度で良好な銀
−錫合金めつき皮膜を形成し得ることを見出し、
ここに本発明を完成した。
即ち、本発明は、
() 銀化合物、
() ２価の錫塩、
() シアン化ナトリウム及び／又はシアン化カ
リウム、並びに
() 糖酸、糖酸の塩、アルドン酸、アルドン酸
の塩、及び糖アルコールの少なくとも１種を含
有する水溶液からなることを特徴とする銀−錫
合金めつき浴に係る。
本発明めつき浴では、錫塩としては、２価の錫
塩であればいずれも使用でき、例えば、硫酸錫
（）、塩化錫（）、酸化錫（）、ピロリン酸錫
（）、スルフアミン酸錫（）、フエノールスル
ホン酸錫（）、アルカノールスルホン酸錫（）
等を単独又は適宜混合して使用できる。錫塩の使
用量は、錫分として、１〜40ｇ／程度が適当で
あり、好ましくは５〜30ｇ／程度とする。
銀塩としては、公知のものがいずれも使用で
き、例えばシアン化銀、シアン化銀カリウム、シ
アン化銀ナトリウム、硝酸銀、硫酸銀、酢酸銀、
シユウ酸銀等を単独又は適宜混合して使用でき
る。銀塩の使用量は、銀分として、１〜50ｇ／
程度が適当であり、好ましくは５〜30ｇ／程度
とする。
錫塩と銀塩の使用割合は、銀分１モルに対し
て、錫分を１〜５モル程度、好ましくは１〜３モ
ル程度とする。
本発明めつき浴では、銀の錯化剤としてシアン
化カリウム及び／又はシアン化ナトリウムを用い
る。シアン化カリウム及び／又はシアン化ナトリ
ウムの使用量は、１〜300ｇ／程度が適当であ
り、好ましくは20〜100ｇ／程度とする。
銀塩とシアン化カリウム及び／又はシアン化ナ
トリウムとの使用割合は、銀分１モルに対してシ
アン化カリウム及び／又はシアン化ナトリウムを
２〜10モル程度、好ましくは５〜10モル程度とす
る。
また、錫の錯化剤として、糖酸、糖酸の塩、ア
ルドン酸、アルドン酸の塩、及び糖アルコールの
少なくとも１種を用いる。糖酸としては、キシロ
糖酸、リボ糖酸、アラボ糖酸、マンノ糖酸、グル
コ糖酸、ノド糖酸、タロ粘液酸、アロ粘液酸、粘
液酸等が使用できる。糖酸の塩としては、これら
の糖酸のナトリウム、カリウム、アンモニウム塩
等が使用できる。アルドン酸としては、グルコン
酸、グルコヘプトン酸、アルトロン酸等が使用で
きる。アルドン酸の塩としては、上記した各種の
アルドン酸のナトリウム、カリウム、アンモニウ
ム塩等が使用できる。糖アルコールとしては、ト
レイツト、エリトリツト、アラビツト、アドニツ
ト、キシリツト、リキシツト、グルシツト、マン
ニツト、イジツト、ソルビツト、ズルシツト、ア
リツト、タリツト、ベルセイツト、ボレミツト、
セドヘプチツト等が使用できる。
錫の錯化剤の使用量は、１〜500ｇ／程度が
適当であり、好ましくは50〜200ｇ／程度とす
る。また、錫分１モルに対する錯化剤の使用量
は、２〜20モル程度が適当であり、好ましくは５
〜15モル程度とする。
上記した錫の錯化剤を用いる場合には、遊離の
シアン化合物が多量に存在する高PHのめつき浴に
おいても、２価の錫を安定な錯塩として溶解する
ことができる。それ故、銀化合物の還元析出を防
止し得る充分な量のシアン化合物をめつき浴に添
加することができ、安定な銀−錫合金めつき液が
得られる。また、得られるめつき浴は、広範囲の
電流密度において、平滑性のある良好なめつき皮
膜を形成し得るものである。
本発明めつき浴は、PH11〜13程度に調整して用
いられる。PH調整は、水酸化ナトリウム、水酸化
カリウム等によつて行なえばよい。
本発明めつき浴では、浴温25〜50℃程度、陰極
電流密度0.1〜5A／ｄm2程度の条件でめつきを行
なうことができ、通常、機械攪拌下でめつきを行
なえばよい。
本発明めつき浴では、浴中の組成や作業条件が
多少変動しても、形成されるめつき皮膜中の銀−
錫量の比率の変化は少なく、通常ほぼ13〜17％程
度の錫含有量のめつき皮膜が形成される。
本発明のめつき浴の使用に際しては、従来のめ
つき方法となんら異なる工程あるいは技法を必要
としない。即ち、常法に従つてバフ研磨、脱脂、
希酸浸等の前処理を行なつた後、必要に応じて、
銅、銀等によるストライクめつきを行ない、陽極
として、白金めつきチタン板、ステンレス板、カ
ーボン板、銀板等を用いて銀−錫合金めつきを行
なつた後、水洗、洗浄、乾燥などの処理を行なえ
ばよい。
発明の効果
本発明は銀−錫合金めつき浴は、銀、錫等の化
合物が自然に析出することのない安定性に優れた
ものであつて、広範囲の電流密度において、平滑
性のある良好なめつき皮膜を形成できる。このた
め、該めつき浴は、バレルめつきや複雑な形状物
のめつき時に生じる広範囲の電流密度のばらつき
に十分に対応し得るものである。また、析出する
合金めつき皮膜は、電気抵抗が低く、良好なハン
ダ付け性を有し、かつ耐変色性に優れた有用性の
高いものである。
実施例
以下に実施例を挙げ本発明の特徴を更に詳しく
説明する。
実施例 １〜９
下記第１表に示す各組成のめつき浴を使用し
て、第１表に示すPH、浴温度、陰極電流密度にお
いて攪拌下にめつきを行なつた。被めつき物は、
あらかじめバフ研磨、アルカリ脱脂、希酸浸漬を
施した真鍮板である。得られた各めつき皮膜の銀
含有率及び錫含有率を第１表に示す。尚、めつき
皮膜は、約10μｍとした。
INDUSTRIAL APPLICATION FIELD OF THE INVENTION The present invention relates to a silver-tin alloy plating bath. BACKGROUND ART AND PROBLEMS Silver has the lowest electrical resistance among metals and has good solderability, so it is widely used as silver plating in fields such as the electrical industry and electric industry. However, silver has the disadvantage that it is susceptible to discoloration due to the formation of sulfides in the atmosphere, and after silver plating, it is usually necessary to carry out post-treatment to prevent discoloration. On the other hand, from a metallurgical point of view, it is known that a silver-tin alloy, in which tin is added to silver, has the excellent properties of silver and has excellent discoloration resistance. Conventionally, known silver-tin alloy plating baths include a plating bath containing a silver cyanide compound and a stannate as basic ingredients, a plating bath containing a silver cyanide compound and a tin pyrophosphate complex salt as basic ingredients, and the like. It has been confirmed that silver-tin alloy films obtained from these plating baths also have excellent discoloration resistance. In such a plating bath that uses silver cyanide as a silver component, it is necessary to have a large amount of free potassium cyanide, sodium cyanide, etc. in the plating bath in order to avoid reduction precipitation of silver. Plating solutions that use large amounts of cyanide compounds typically have a high pH of 11 or higher. However, in such a high pH plating bath, when stannate is used as the tin component, tin ions become tetravalent ions and are difficult to precipitate into the plating film.
Therefore, unless the silver ion concentration in the bath is kept extremely low and the tin ion ratio is extremely high, the silver
It is not possible to obtain a tin alloy plating film. However, if there is an extreme concentration difference between silver ions and tin ions, it becomes difficult to manage the plating bath and it becomes difficult to stably deposit an alloy film at a certain ratio, making it impractical as a plating bath. On the other hand, in a plating bath that uses pyrophosphoric acid as a tin complexing agent, pyrophosphoric acid and tin form a stable complex at a pH of about 8 to 10, so in a high pH state of 11 or higher, the stability of the complex is poor. , precipitation of tin dioxide is likely to occur. Furthermore, all of the above-mentioned plating baths have the disadvantage that the current density range in which a good plating film can be obtained is very narrow. Means for Solving the Problems In view of the current situation as described above, the present inventor aimed to obtain a silver-tin alloy plating bath that is highly stable and capable of forming a good plating film over a wide range of current densities. I have conducted extensive research. As a result, when at least one compound selected from sugar acid or its salt, aldonic acid or its salt, and sugar alcohol is used as a tin complexing agent, a tin complex salt is stable even in a high pH state of PH11 or higher. is formed, making it possible for tin compounds to exist as stable complex salts even in high pH plating baths containing large amounts of silver compound complexing agents such as potassium cyanide and sodium cyanide. We have discovered that a soaking bath obtained using a complexing agent can form a good silver-tin alloy plating film over a wide range of current densities,
The present invention has now been completed. That is, the present invention provides () a silver compound, () a divalent tin salt, () sodium cyanide and/or potassium cyanide, and () a sugar acid, a salt of a sugar acid, an aldonic acid, a salt of an aldonic acid, and a sugar. The present invention relates to a silver-tin alloy plating bath characterized by comprising an aqueous solution containing at least one kind of alcohol. In the plating bath of the present invention, any divalent tin salt can be used as the tin salt, such as tin sulfate (), tin chloride (), tin oxide (), tin pyrophosphate (), and sulfamic acid. Tin (), tin phenolsulfonate (), tin alkanolsulfonate ()
These can be used alone or in appropriate mixture. The appropriate amount of tin salt to be used is approximately 1 to 40 g/approx., preferably 5 to 30 g/approx. Any known silver salt can be used, such as silver cyanide, silver potassium cyanide, silver sodium cyanide, silver nitrate, silver sulfate, silver acetate,
Silver oxalate and the like can be used alone or in combination as appropriate. The amount of silver salt used is 1 to 50g/silver content.
The amount is appropriate, preferably about 5 to 30 g/. The proportion of tin salt and silver salt to be used is about 1 to 5 moles, preferably about 1 to 3 moles of tin per mole of silver. In the plating bath of the present invention, potassium cyanide and/or sodium cyanide are used as a silver complexing agent. The amount of potassium cyanide and/or sodium cyanide to be used is suitably about 1 to 300 g/, preferably about 20 to 100 g/. The ratio of silver salt to potassium cyanide and/or sodium cyanide is about 2 to 10 moles, preferably about 5 to 10 moles, per mole of silver. Further, as a tin complexing agent, at least one of a sugar acid, a salt of a sugar acid, an aldonic acid, a salt of an aldonic acid, and a sugar alcohol is used. As the sugar acid, xylo-sugar acid, ribo-sugar acid, arabo-sugar acid, manno-sugar acid, gluco-sugar acid, nodo-sugar acid, talomucacic acid, allomucacid acid, mucinic acid, etc. can be used. As the sugar acid salt, sodium, potassium, ammonium salts, etc. of these sugar acids can be used. As the aldonic acid, gluconic acid, glucoheptonic acid, altronic acid, etc. can be used. As the aldonic acid salt, the sodium, potassium, ammonium salts, etc. of the various aldonic acids mentioned above can be used. Examples of sugar alcohols include Trait, Erythrit, Arabit, Adnit, Xylit, Lixit, Glucit, Mannit, Izit, Sorbit, Sulcit, Aritz, Talit, Berseit, Boremit,
Sedoheptitate etc. can be used. The amount of tin complexing agent used is suitably about 1 to 500 g/approx, preferably about 50 to 200 g/approx. The appropriate amount of the complexing agent to be used per 1 mol of tin is about 2 to 20 mol, preferably 5 to 20 mol.
The amount should be about 15 moles. When the above tin complexing agent is used, divalent tin can be dissolved as a stable complex salt even in a high pH plating bath in which a large amount of free cyanide compounds are present. Therefore, a sufficient amount of a cyanide compound capable of preventing reduction precipitation of silver compounds can be added to the plating bath, and a stable silver-tin alloy plating solution can be obtained. Furthermore, the resulting plating bath can form a smooth and good plating film over a wide range of current densities. The plating bath of the present invention is used after adjusting the pH to about 11 to 13. PH adjustment may be performed using sodium hydroxide, potassium hydroxide, or the like. In the plating bath of the present invention, plating can be carried out under the conditions of a bath temperature of about 25 to 50°C and a cathode current density of about 0.1 to 5 A/dm 2 , and usually plating can be carried out under mechanical stirring. In the plating bath of the present invention, even if the bath composition and working conditions vary slightly, the silver in the plating film formed is
There is little change in the proportion of tin, and a plating film with a tin content of about 13 to 17% is usually formed. Use of the plating bath of the present invention does not require any different steps or techniques from conventional plating methods. That is, buffing, degreasing, and
After pretreatment such as dilute acid immersion, if necessary,
After strike plating with copper, silver, etc., and silver-tin alloy plating using a platinum-plated titanium plate, stainless steel plate, carbon plate, silver plate, etc. as an anode, washing with water, washing, drying, etc. All you have to do is process. Effects of the Invention The present invention provides a silver-tin alloy plating bath that has excellent stability without spontaneous precipitation of compounds such as silver and tin, and has good smoothness over a wide range of current densities. Can form a tanned film. Therefore, the plating bath can sufficiently cope with a wide range of current density variations that occur during barrel plating or plating of complex-shaped objects. Furthermore, the deposited alloy plating film has low electrical resistance, good solderability, and excellent discoloration resistance, making it highly useful. Examples The features of the present invention will be explained in more detail with reference to Examples below. Examples 1 to 9 Using plating baths having the compositions shown in Table 1 below, plating was carried out under stirring at the pH, bath temperature, and cathode current density shown in Table 1. The covering is
This is a brass plate that has been previously buffed, alkaline degreased, and diluted in dilute acid. Table 1 shows the silver content and tin content of each of the plated films obtained. The plating film was approximately 10 μm thick.
【表】【table】
【表】【table】
【表】
得られた銀−錫合金めつき皮膜は、いずれも良
好な外観を有し、硫化水素雰囲気中において優れ
た耐変色性を示した。[Table] All of the obtained silver-tin alloy plating films had a good appearance and exhibited excellent discoloration resistance in a hydrogen sulfide atmosphere.
Claims (1)
リウム、並びに () 糖酸、糖酸の塩、アルドン酸、アルドン酸
の塩、及び糖アルコールの少なくとも１種 を含有する水溶液からなることを特徴とする銀−
錫合金めつき浴。[Scope of Claims] 1 () a silver compound, () a divalent tin salt, () sodium cyanide and/or potassium cyanide, and () a sugar acid, a salt of a sugar acid, an aldonic acid, a salt of an aldonic acid, and Silver characterized by comprising an aqueous solution containing at least one kind of sugar alcohol.
Tin alloy plating bath.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19890787A JPS6442594A (en) | 1987-08-07 | 1987-08-07 | Silver-tin alloy plating bath |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19890787A JPS6442594A (en) | 1987-08-07 | 1987-08-07 | Silver-tin alloy plating bath |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6442594A JPS6442594A (en) | 1989-02-14 |
| JPH0321638B2 true JPH0321638B2 (en) | 1991-03-25 |
Family
ID=16398928
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19890787A Granted JPS6442594A (en) | 1987-08-07 | 1987-08-07 | Silver-tin alloy plating bath |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6442594A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6172811B2 (en) * | 2014-03-24 | 2017-08-02 | Ｊｘ金属株式会社 | Ag-Sn alloy plating solution and method for manufacturing electronic component |
| JP6207655B1 (en) * | 2016-04-12 | 2017-10-04 | 日本エレクトロプレイテイング・エンジニヤース株式会社 | Non-cyan Au-Sn alloy plating solution |
| JP2022108290A (en) * | 2021-01-13 | 2022-07-26 | 三菱マテリアル株式会社 | Tin alloy plating solution |
-
1987
- 1987-08-07 JP JP19890787A patent/JPS6442594A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6442594A (en) | 1989-02-14 |
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