ʻO ke Kaʻina Hana Zinc Sodium Cyanide Electroplating: He Kaʻina Hana Kūʻai

Introduction

ʻO ka electroplating kahi hana i hoʻohana nui ʻia i nā ʻoihana like ʻole e hoʻomaikaʻi i nā waiwai o nā ʻili metala. Ma waena o nā ʻano hana electroplating like ʻole, ʻO ka sodium Cyanide paʻa ka zinc electroplating i kahi kūlana koʻikoʻi ma muli o kāna mau hiʻohiʻona kūikawā a me nā pono. Makemake kēia ʻatikala e hāʻawi i kahi kikoʻī kikoʻī o ka ʻO ka sodium cyanide electroplating zinc kaʻina hana, e uhi ana i kona mau loina, kaʻina hana, ka ʻauʻau ʻauʻau, a me nā manaʻo hana.

Nā Kumu o ka Sodium Cyanide Electroplating Zinc

I ka ka sodium cyanide ʻO ke kaʻina hana zinc electroplating, ʻo ke kumu nui e pili ana i ka electrolysis. Aia ka ʻauʻau electroplating i nā ion zinc a me nā mea ʻē aʻe. Ke hoʻohana ʻia ke au uila, hoʻemi ʻia nā ion zinc i loko o ka ʻauʻau ma ka cathode (ka mea e hoʻopaʻa ʻia), a waiho ʻia nā ʻātoma zinc ma ka ʻili o ka cathode, e hana ana i kahi uhi zinc. Ka noho ana o ʻO Sodium cyanide i loko o ka ʻauʻau he kuleana koʻikoʻi. Hana ʻo ia ma ke ʻano he mea paʻakikī, e hana ana i nā paʻa paʻa me nā ion zinc. Kōkua kēia paʻakikī i ka mālama ʻana i ka helu deposition o ka zinc a hoʻomaikaʻi i ka maikaʻi o ka papa zinc i waiho ʻia. No ka laʻana, hiki ke hōʻike wale ʻia ka pane e like me: Zn(CN)₄²⁻ + 2e⁻ → Zn + 4CN⁻ ma ka cathode. ʻO nā ion zinc paʻakikī i ke ʻano o Zn(CN)₄²⁻ ʻoi aku ka paʻa i ka ʻauʻau, kahi e alakaʻi ai i kahi hoʻoheheʻe zinc ʻoi aʻe a ʻoi aku ka maikaʻi ma mua o nā ʻōnaehana paʻakikī ʻole.

Ke Kaʻina Hana

1. Hoʻomaʻamaʻa mua ʻia o ka substrate

Ma mua o ka electroplating, pono e hoʻomaʻamaʻa mua ʻia ka substrate (ka mea metala e uhi ʻia). Pono kēia ʻanuʻu e hōʻoia i ka hoʻopili maikaʻi ʻana o ka uhi zinc.

• Degreasing: Hoʻohemo mua ʻia ka substrate e wehe i kekahi aila, momona, a i ʻole nā ​​​​mea haumia organik ma kona ʻili. Hiki ke hoʻokō ʻia kēia ma o nā ʻano hana e like me ka alkaline degreasing, kahi e hoʻokomo ʻia ai ka substrate i loko o kahi hopena alkaline e loaʻa ana nā surfactants. Hoʻopili ka hopena alkaline me ka momona, e hoʻopili ana iā ia a ʻae ʻia e holoi ʻia. No ka laʻana, hiki i kahi hopena alkaline degreasing maʻamau ke loaʻa ka sodium hydroxide, sodium Keleponaʻai, a me nā surfactants e like me ka sodium dodecyl sulfate.

• ʻIkepili: Ma hope o ka degreasing, lawe ʻia ka pickling e wehe i ka ʻōpala, oxides, a me nā mea haumia ʻē aʻe mai ka ʻili substrate. Hoʻohana maʻamau ʻia kahi hopena waika, e like me ka waika hydrochloric a i ʻole sulfuric acid, no ka pickling. Hoʻopili ka ʻakika me nā oxides ma ka ʻili, e hoʻoheheʻe iā lākou. No ka laʻana, inā ʻo ka ʻōpala (iron oxide) ma kahi pani kila, ʻo ka pane ʻana me ka waikawa hydrochloric: Fe₂O₃ + 6HCl → 2FeCl₃ + 3H₂O. Ma hope o ka pickling, holoi maikaʻi ʻia ka substrate me ka wai e hoʻoneʻe i ke koena waikawa.

2. Hoʻomākaukau ʻana i ka ʻauʻau Electroplating

ʻO ka hoʻomākaukau ʻana i ka ʻauʻau electroplating kahi hana koʻikoʻi i ka sodium cyanide kaʻina hana zinc electroplating.

• nā mea hoʻohui: ʻO nā mea nui o ka ʻauʻau ʻo ia ka zinc oxide (ZnO) ma ke ʻano he kumu o nā ion zinc, sodium cyanide (NaCN) ma ke ʻano he mea paʻakikī, a me ka sodium hydroxide (NaOH) ma ke ʻano he paʻakai conductive. Eia kekahi, hiki ke hoʻohui ʻia nā mea hoʻohui ʻē aʻe e hoʻomaikaʻi i ka maikaʻi o ka plating, e like me nā mea hoʻomālamalama. No ka ʻauʻau electroplating haʻahaʻa haʻahaʻa maʻamau, ʻo ka haku mele: ZnO 8 - 12 g/L, NaCN 10 - 20 g/L, NaOH 80 - 120 g/L.

• Kaʻina huikau: ʻO ka mua, hoʻohui ʻia kahi ʻāpana o ka wai (ma kahi o hoʻokahi - hapakolu o ka nui o ka ʻauʻau ʻauʻau) i ka pahu paʻi. A laila, hoʻohui ʻia ka nui o ka sodium cyanide a me ka sodium hydroxide a hoʻoulu ʻia a pau loa. A laila, hoʻohui mālie ʻia ka zinc oxide i ka hopena me ka hoʻoulu ʻana. Hoʻopili ka Zinc oxide me ka sodium hydroxide a me ka sodium cyanide e hana i nā paʻakikī e pono ai. Ma hope o ka hoʻohui ʻana o ka zinc oxide, hoʻoheheʻe ʻia ka ʻauʻau i ka nui i makemake ʻia me ka wai. ʻO ka hope, hoʻohui ʻia nā mea hoʻohui e like me nā ʻōlelo a ka mea hana.

3. Kaʻina Electroplating

• Hoʻonohonoho i ka Electroplating Cell: Aia i loko o ke kelepona electroplating ka ʻauʻau plating, ka cathode (ke substrate e hoʻopaʻa ʻia), a me ka anode. Hana ʻia ka anode me ka metala zinc. Ke hoʻoheheʻe ʻia ke au uila ma ka ʻauʻau, hoʻoheheʻe ʻia nā ion zinc mai ka anode i loko o ka ʻauʻau a waiho ʻia ma ka cathode. ʻO ka mānoanoa o kēia manawa, ʻo ia ka nui o kēia manawa no kēlā me kēia ʻāpana o ka cathode, e mālama pono ʻia. No ka sodium cyanide electroplating zinc, ʻo ka mānoanoa maʻamau o kēia manawa mai 1 - 5 A/dm². Hiki i ka ha'aha'a ha'aha'a o kēia manawa ke hopena i ka lohi o ka waiho 'ana akā hiki ke alaka'i i ka 'a'ahu a 'oi aku ka maika'i. Ma ka ʻaoʻao ʻē aʻe, hiki i ka nui o kēia manawa ke hoʻonui i ka helu deposition akā hiki ke hoʻoulu i nā pilikia e like me ka pale ʻole ʻana a me ka puhi ʻana o ka uhi ma nā wahi kiʻekiʻe.

• Ka Mahana a me ka Haʻalulu: Hoʻopili pū ka mahana o ka ʻauʻau electroplating i ke kaʻina hana plating. ʻO ka maʻamau, mālama ʻia ka mahana ʻauʻau ma waena o 20 - 40 °C. Hiki i nā mahana kiʻekiʻe ke hoʻonui i ka helu deposition akā hiki ke hōʻemi i ka polarization cathode, e alakaʻi ana i kahi uhi ʻoi ʻoi loa. He mea nui ka hoʻoulu ʻana o ka ʻauʻau e hōʻoia i ka hāʻawi like ʻana o nā ion a puni ka cathode. Hiki ke hoʻokō ʻia kēia ma o ka hoʻoulu ʻana i ka mīkini, e like me ka hoʻohana ʻana i ka mea hoʻoheheʻe, a i ʻole ma ka ʻūhū ʻana o ka ea. Kōkua ka hoʻoulu ʻana i ka hoʻopiha ʻana i nā ion zinc ma kahi kokoke i ka ʻili cathode, e pale ana i ka hoʻokumu ʻia ʻana o nā gradients noʻonoʻo e hiki ke alakaʻi i ka hoʻopaʻa ʻole ʻana.

4. Mahope - lapaau

• ʻO ka holoiʻana: Ma hope o ka electroplating, holoi maikaʻi ʻia ka mea i hoʻopaʻa ʻia me ka wai e hoʻoneʻe i ke koena o ka hopena plating ma luna o kona ʻili. Hiki ke hana ʻia nā ʻanuʻu hoʻomaʻemaʻe he nui, me ka holoi mua ʻana i loko o ka wai anuanu e wehe i ka nui o ka hopena, a ukali ʻia e nā holoi holoi hou i ka wai maʻemaʻe e hōʻoia i ka wehe piha ʻana i nā mea haumia.

• ʻO ka Chromating: Hoʻohana pinepine ʻia ka Chromating no ka hoʻomaikaʻi ʻana i ke kūpaʻa ʻino o ka papa zinc-plated. Hoʻokomo ʻia ka mea i hoʻopaʻa ʻia i loko o kahi solution chromating, aia ka chromic acid a i ʻole kona mau paʻakai. Hoʻokumu ke kaʻina hana chromating i kahi ʻāpana hoʻololi chromate ʻili a pale ma ka ʻili o ka uhi zinc. Hāʻawi kēia papa i ka pale hou aku i ka ʻinoʻino ma o ka hana ʻana ma ke ʻano he mea pale a me ka hoʻōla ʻana iā ia iho i kekahi manawa ke ʻoki ʻia ka ʻili. Aia nā ʻano chromating like ʻole, e like me ka chromating melemele, chromating uliuli - keʻokeʻo, a me ka chromating ʻeleʻele, hāʻawi kēlā me kēia me nā pae like ʻole o ka pale ʻana i ka corrosion a me nā hiʻohiʻona nani.

• ʻOhi: ʻO ka hope, maloʻo ka mea i hoʻopaʻa ʻia a chromated. No nā ʻāpana liʻiliʻi, hiki ke hoʻomaloʻo ʻia i loko o kahi mea maloʻo centrifugal me ka ea wela, ʻoiai ʻo nā ʻāpana nui e hoʻomaloʻo ʻia i ka mahana wela. He mea nui ka hoʻomaloʻo ʻana i mea e pale ai i ka hoʻokumu ʻana o nā wahi wai a me ka hōʻoia ʻana i ka paʻa lōʻihi o ka uhi.

ʻO ka ʻauʻau ʻauʻau a me kona mana

1. Zinc Oxide (ZnO)

ʻO Zinc oxide ke kumu o nā ion zinc i loko o ka ʻauʻau electroplating. Hoʻopili ka ʻike o ka zinc oxide i ka ʻauʻau i ka helu deposition o ka zinc. ʻO ke kiʻekiʻe o ka zinc oxide e alakaʻi i kahi kiʻekiʻe o ka deposition rate. Eia nō naʻe, inā kiʻekiʻe loa ka manaʻo o ka zinc ion, hiki iā ia ke hoʻoulu i nā pilikia e like me ka maikaʻi ʻole o ka hoʻolei ʻana i ka mana (ka hiki i ka hoʻonā plating ke waiho i kahi uhi ʻaʻahu ma luna o nā mea paʻakikī) a me ka uhi ʻana i ka palaoa. I loko o nā ʻauʻau haʻahaʻa cyanide, ʻo ka nui o ka zinc oxide kūpono i ka laulā i ʻōlelo ʻia ma mua (8 - 12 g/L), e hāʻawi ana i ke kaulike ma waena o ka helu deposition a me ka maikaʻi o ka uhi.

2. Sodium Cyanide (NaCN)

Hana ʻia ka sodium cyanide ma ke ʻano he mea paʻakikī i ka ʻauʻau. Hoʻokumu ia i nā paʻakikī me nā ion zinc, e like me Zn(CN)₄²⁻. Hoʻopili ka neʻe ʻana o ka sodium cyanide i ka paʻa o kēia mau paʻakikī a, no laila, ke ʻano deposition o ka zinc. I loko o nā ʻauʻau kiʻekiʻe - cyanide, hoʻohana ʻia kahi ʻano kiʻekiʻe o ka sodium cyanide, kahi e hāʻawi ai i ka mana hoʻolei maikaʻi loa a me ka uhi ʻana i ka palaoa maikaʻi loa. Eia nō naʻe, ʻo nā ʻauʻau kiʻekiʻe-cyanide ke kumu nui o ka pōʻino a me ka palekana ma muli o ke ʻona o ka cyanide. ʻO ka ʻokoʻa, nā ʻauʻau haʻahaʻa - cyanide, i hoʻohana pinepine ʻia i kēia mau lā, e hoʻohana i ka haʻahaʻa haʻahaʻa o ka sodium cyanide (e laʻa, 10 - 20 g/L). Hāʻawi kēia mau ʻauʻau i ka mana hoʻolei maikaʻi a me ka maikaʻi o ka uhi ʻana i ka wā e hōʻemi ana i ka hopohopo kaiapuni a me ka palekana. ʻO ka ratio o ka sodium cyanide i ka zinc oxide (NaCN/ZnO ratio) he mea nui hoʻi. ʻO ka ratio kūpono e hōʻoia i ka hoʻokumu ʻana o nā paʻakikī paʻa a me nā kūlana plating maikaʻi loa. No ka laʻana, ma kekahi mau noi, makemake ʻia kahi ratio NaCN/ZnO ma kahi o 1.5 - 2.5.

3. Sodium Hydroxide (NaOH)

Hana ka sodium hydroxide ma ke ʻano he paʻakai conductive i ka ʻauʻau, e hoʻonui ana i ka conductivity uila o ka hopena. Hāʻawi kēia i ka hoʻololi maikaʻi ʻana o kēia manawa i ka wā electroplating. He kōkua nō hoʻi e mālama i ka pH o ka ʻauʻau. ʻO ka pH o ka ʻauʻau zinc electroplating sodium cyanide ma ke ʻano maʻamau, ma kahi o ka pH 12 - 14. He mea nui ka pH paʻa no ka paʻa o nā paʻakikī a me ke kaʻina hana plating holoʻokoʻa. Inā haʻahaʻa loa ka pH, hiki ke hoʻoheheʻe ʻia nā paʻakikī, e alakaʻi ana i nā hopena plating maikaʻi ʻole. Ma ka ʻaoʻao ʻē aʻe, inā kiʻekiʻe ka pH, hiki iā ia ke hoʻoulu i nā pilikia e like me ka corrosion nui o ka anode a me ka hoʻokumu ʻana o ka zinc hydroxide precipitates i ka ʻauʻau.

4. Nā mea hoʻohui

• Nā mea hoʻomālamalama: Hoʻohui ʻia nā mea hoʻomālamalama i ka ʻauʻau e hoʻomaikaʻi i ka ʻōlinolino a me ka luster o ka uhi zinc. Hana lākou ma ka hoʻololi ʻana i ka morphology ili o ka papa zinc i waiho ʻia ma ka pae atomika. Hoʻohana mau ʻia nā mea hoʻohuihui e like me saccharin, coumarin, a me kekahi mau paʻakai ammonium quaternary i mea hoʻomālamalama. No ka laʻana, hiki i ka saccharin ke adsorb ma ka ʻili o ka cathode i ka wā electroplating, ke kāohi ʻana i ka ulu ʻana o nā kristal zinc i kekahi mau kuhikuhi a me ka hoʻoikaika ʻana i ka hoʻokumu ʻia ʻana o kahi ʻano maʻalahi a mālamalama.

• Papa pae: Kōkua nā mea hoʻohālikelike i ka hoʻomaʻemaʻe ʻana i nā ʻano like ʻole ma ka ʻili o ka substrate i ka wā electroplating. Makemake lākou e waiho ma nā wahi kiʻekiʻe - o kēia manawa - ʻoi aku ka nui o ka substrate, e hōʻemi ana i ka ʻokoʻa mānoanoa ma waena o nā ʻāpana kiʻekiʻe - a me nā ʻāpana haʻahaʻa - i kēia manawa a me ka hopena i kahi uhi ʻokoʻa. Hiki i kekahi mau polymers a me nā surfactants ke hana ma ke ʻano he pae i loko o ka ʻauʻau electroplating.

• Nā Antioxidants a me nā Stabilizers: Hoʻohana ʻia kēia mau mea hoʻohui i mea e pale ai i ka oxidation o nā mea i loko o ka ʻauʻau, ʻoi aku ka nui o nā ion cyanide. Hiki ke oxidized ka cyanide i ke alo o ka ea a me kekahi mau mea haumia, hiki ke alakaʻi i ka emi ʻana o ka pono o ka mea paʻakikī a me nā loli i ka kemika ʻauʻau. Hiki ke hoʻohui ʻia nā antioxidants e like me ka sodium sulfite i ka ʻauʻau e hoʻopau i ka oxygen a pale i ka hoʻoheheʻe ʻana o ka cyanide. Hoʻohui pū ʻia nā stabilizers e mālama i ka paʻa o ka ʻauʻau i ka manawa, e hōʻoia i nā hopena plating mau.

Manaʻo Operational

1. Ka Maluhia o ka Lehulehu

No ka mea he mea ʻawaʻawa loa ka sodium cyanide, pono e mālama pono i ka mālama ʻana a me ka hana ʻana o ke kaʻina hana electroplating. Pono nā limahana a pau e komo i ke kaʻina hana e ʻaʻahu i nā lako pale pilikino kūpono, me nā mīkina lima, nā maka aniani, a me nā respirator. Pono e hoʻoheheʻe maikaʻi ʻia ka wahi electroplating e pale ai i ka hōʻiliʻili ʻana o nā uahi ʻona. I ka hihia o kekahi kahe a i ʻole nā ​​pōʻino e pili ana i ka sodium cyanide, pono e hahai koke i nā kaʻina hana hoʻoponopono ulia pōpilikia. Hiki i kēia ke komo i ka pale ʻana i ka cyanide me nā kemika kūpono (e like me ka hypochlorite solutions) a me ka hoʻolaha ʻana i nā luna palekana kūpono.

2. Mālama ʻauʻau

• ʻIkepili mau: Pono e nānā mau ʻia ke ʻano o ka ʻauʻau electroplating e hōʻoia i ka nui o ka nui o ka zinc oxide, sodium cyanide, sodium hydroxide, a me nā mea hoʻohui. Hiki ke hoʻohana ʻia nā ʻano analytical e like me ka titration no ka hoʻoholo ʻana i ke ʻano o kēia mau ʻāpana. No ka laʻana, hiki ke hoʻoholo ʻia ka neʻe ʻana o nā ion zinc ma ka titrating i kahi laʻana o ka ʻauʻau me kahi hopena EDTA (ethylenediaminetetraacetic acid) maʻamau.

• Ka hoʻomāinoino ʻana: Hiki ke hoʻohaumia i ka ʻauʻau mai nā kumu like ʻole, e like me nā haumia i loko o nā mea maka, 带入 o nā mea ʻē aʻe mai ka substrate i ka wā o ka plating, a me ke kūkulu ʻana o ka hopena e nā - huahana. No ka pale ʻana i ka haumia, pono e hoʻokō ʻia ka kānana kūpono o ka ʻauʻau. Hiki i kahi ʻōnaehana kānana me ka media kānana kūpono ke wehe i nā ʻāpana paʻa a me kekahi mau mea haumia. Eia kekahi, pono ka hoʻomaʻemaʻe manawa o ka ʻauʻau. No ka laʻana, inā hōʻuluʻulu ʻia nā metala kaumaha (e like me ke keleawe a i ʻole ke kēpau) i loko o ka ʻauʻau, hiki ke hoʻoneʻe ʻia ma ka hoʻohui ʻana i nā kinikona e hoʻoheheʻe ʻia me kēia mau haumia, a ukali ʻia e ka kānana.

• Hoʻopiha hou i nā ʻāpana: Ke holo nei ke kaʻina hana electroplating, pau nā mea i loko o ka ʻauʻau. Waiho ʻia ka Zinc ma ka cathode, a hiki ke hoʻopau ʻia a ʻai ʻia paha kekahi o nā mea paʻakikī a me nā mea hoʻohui. No laila, pono ka hoʻopiha pinepine ʻana o ka zinc oxide, sodium cyanide, sodium hydroxide, a me nā mea hoʻohui e mālama i ka ʻauʻau. Hiki ke hoʻoholo ʻia ka helu o ka hoʻopiha ʻana ma muli o ka manawa plating, ka nui o nā ʻāpana i hoʻopaʻa ʻia, a me nā hopena o ka ʻauʻau ʻauʻau.

3. Nā pilikia pili pilikia

• Hoʻopili ʻino i ka uhi ʻana: Inā maikaʻi ʻole ka hoʻopili ʻana o ka uhi zinc i ka substrate, hiki i nā kumu ke hoʻomaʻamaʻa mua ʻole i ka substrate, ka ʻauʻau ʻauʻau kūpono ʻole (e like me ka pH hewa ʻole a i ʻole ka haʻahaʻa haʻahaʻa o ka mea paʻakikī), a i ʻole nā ​​kiʻekiʻe o ka haumia i ka ʻauʻau. No ka hoʻoponopono ʻana i kēia pilikia, pono e nānā a hoʻoponopono ʻia ke kaʻina hana mua. Pono e nānā ʻia a hoʻoponopono ʻia ka ʻauʻau ʻauʻau inā pono, a pono e hana i nā hana e hōʻemi ai i ka ʻino.

• ʻO ka pāpaʻi like ʻole: Hiki ke hoʻokumu ʻia ka hoʻoheheʻe ʻole ʻia e nā kumu e like me ka hāʻawi pono ʻole ʻana i kēia manawa i loko o ka cell electroplating, ka hoʻoulu ʻole ʻana o ka ʻauʻau, a i ʻole nā ​​ʻano like ʻole o ka geometry o ka substrate. No ka hoʻoponopono ʻana i kēia pilikia, hiki ke hoʻoponopono ʻia ka hoʻonohonoho kelepona electroplating e hōʻoia i ka hāʻawi like ʻana o kēia manawa. Hiki ke hoʻopaʻa ʻia ke ala hoʻonāukiuki, a hiki ke hoʻolālā ʻia nā mea paʻa e hoʻopaʻa i ka substrate ma ke ʻano e hoʻoikaika ai i ka plating like. No nā substrates paʻakikī, pono nā ʻenehana plating kūikawā a i ʻole ka hoʻohana ʻana i nā anodes kōkua.

• Ka uhi ʻeleʻele a ʻeleʻele paha: Ma muli paha o ka lawa ʻole o ka hoʻonaʻauao ʻana i ka ʻauʻau, nā kiʻekiʻe o ka haumia, a i ʻole nā ​​ʻāpana hoʻoheheʻe hewa ʻole (e like me ke kiʻekiʻe kiʻekiʻe o kēia manawa a i ʻole ka wela ʻauʻau). Pono e nānā ʻia a hoʻoponopono ʻia ka manaʻo hoʻomālamalama inā pono. Pono e hoʻomaʻemaʻe ʻia ka ʻauʻau e wehe i nā mea haumia, a pono e hoʻomaikaʻi ʻia nā ʻāpana plating.

Panina

ʻO ke kaʻina hana zinc electroplating sodium cyanide he ʻano hoʻohana nui a koʻikoʻi no ka hāʻawi ʻana i ka pale ʻana i ka corrosion a me ka hoʻopau hoʻonaninani i nā mea metala. He mea koʻikoʻi ka hoʻomaopopo ʻana i kāna mau loina, nā kaʻina hana, ka ʻauʻau ʻauʻau, a me nā noʻonoʻo hana no ka loaʻa ʻana o nā hopena plating kiʻekiʻe. ʻOiai aia kekahi mau pilikia kaiapuni a me ka palekana e pili ana i ka hoʻohana ʻana i ka sodium cyanide, me nā ana palekana kūpono a me ka hoʻomohala ʻana i nā mea ʻē aʻe e pili ana i ke kaiapuni (e like me ka haʻahaʻa - cyanide a i ʻole cyanide - nā kaʻina manuahi), ke hoʻomau nei ka hana nui i nā ʻoihana like ʻole, me ka automotive, aerospace, a me nā uila. Ma ka mālama pono ʻana i nā ʻano āpau o ke kaʻina hana, hiki i nā mea hana ke hana i nā huahana zinc-plated me ka maikaʻi a me ka hana.