Hōʻike kēia pepa i nā manaʻo ʻenehana o ka hoʻomohala ʻana i nā kīwaha electroplating

Hōʻike kēia pepa i nā manaʻo ʻenehana o ka hoʻomohala ʻana i nā kiwi electroplating ʻEkolu yuan ethylene propylene ahi paipu kāleka e hoʻopaʻa ana i ke apo pulupulu, 63-65 Shaw A,15MPA, kaomi mau ma lalo o 25% o ka hoʻolālā hoʻohui waiwai. ʻO ka hoʻopaʻa ʻana i ka wai (gas, wai) he ʻenehana maʻamau e pono ai i nā ʻoihana ʻoihana like ʻole, ʻaʻole wale ke kūkulu ʻana, petrochemical, ka hana moku, ka hana mīkini, ka ikehu, ka lawe ʻana, ka mālama ʻana i ke kaiapuni a me nā ʻoihana ʻē aʻe ʻaʻole hiki ke hana me ka ʻole o ka hoʻopaʻa ʻana i ka ʻenehana, aviation, aerospace a me nā mea ʻē aʻe. pili loa nā ʻoihana i ka ʻenehana hoʻopaʻa. ʻO ke kahua o ka hoʻohana ʻana i ka ʻenehana sealing ua holomua loa. ʻO nā mea hana a pau e pili ana i ka mālama ʻana i ka wai, ka lawe ʻana a me ka hoʻololi ʻana i ka ikehu, loaʻa nā pilikia sila. ʻO ka mea mua, e hoʻoholo i nā hōʻailona hana o nā pono a me nā pōʻino o nā mea hoʻopaʻa inoa 1 ʻO nā waiwai Tensile nā ​​waiwai mua e noʻonoʻo ʻia no ka hoʻopaʻa ʻana i nā mea, ʻo ia hoʻi ka ikaika tensile, ke koʻikoʻi elongation mau, ka elongation ma ka haʻihaʻi a me ka deformation lōʻihi i ka wā hoʻomaha. ʻO ka ikaika tensile ke koʻikoʻi nui o kahi laʻana mai ka tensile a i ka haki. ʻO ke koʻikoʻi elongation mau (modulu elongation mau) ʻo ia ke koʻikoʻi i loaʻa i ka elongation i kuhikuhi ʻia. ʻO ka elongation ka deformation o ka specimen ma lalo o kahi ikaika tensile i kuhikuhi ʻia, a ʻo ia ka ratio o ka hoʻonui ʻana o ka elongation i ka lōʻihi kumu. ʻO ka elongation ma ka haʻihaʻi ka elongation o ka specimen i ka haki. ʻO ka deformation tensile lōʻihi ke koena deformation ma waena o nā kaha ma hope o ka haki ʻana. 2 ka paʻakikī ʻO ka paʻakikī e hōʻike ana i ka hiki o ka mea hoʻopaʻa paʻa ke kū'ē i ka ikaika o waho i loko o ka mea hoʻopaʻa, ʻo ia kekahi o nā waiwai kumu o ka mea hoʻopaʻa. ʻO ka paʻakikī o ka mea pili i nā waiwai ʻē aʻe i kekahi ʻano. ʻO ke kiʻekiʻe o ka paʻakikī, ʻoi aku ka nui o ka ikaika, ʻoi aku ka liʻiliʻi o ka elongation, ʻoi aku ka maikaʻi o ka pale ʻana, a ʻoi aku ka maikaʻi o ka haʻahaʻa haʻahaʻa haʻahaʻa. 3 Hoʻokō hoʻoemi ʻia ʻO nā sila Rubber ma kahi kūlana paʻa. Ma muli o ka viscoelasticity o nā mea lāʻau lapaʻau, e emi iho ke kaomi me ka manawa i hoʻopaʻa ʻia, i hōʻike ʻia e like me ka hoʻomaha ʻana o ke koʻikoʻi compressive. Ma hope o ka wehe ʻana i ke kaomi, ʻaʻole hiki ke hoʻi i ke ʻano kumu, i hōʻike ʻia e like me ka deformation compression no ka manawa lōʻihi. ʻOi aku ka ʻike o kēia ʻano i ka wela kiʻekiʻe a me ka ʻaila ʻaila, e pili pono ana i ka lōʻihi o ka hiki ke hoʻopaʻa ʻia o ka huahana sealing. 4 Haʻahaʻa wela hana No ke ana ʻana i nā hiʻohiʻona haʻahaʻa haʻahaʻa o nā sila lāʻau lapaʻau, ua hoʻokomo ʻia nā ʻano ʻelua o ka hoʻāʻo ʻana i ka hana haʻahaʻa haʻahaʻa: (1) Haʻahaʻa haʻahaʻa haʻahaʻa hoʻihoʻi ʻana i ka wela: ua hoʻopaʻa ʻia ka mea sila i kekahi lōʻihi, a laila hoʻopaʻa ʻia, hoʻomaha wikiwiki. i lalo o ka mahana wela, hiki i ke kaulike, hoʻokuʻu i ka ʻāpana hoʻāʻo, a ma kahi ʻano o ka mahana, e hoʻopaʻa i ka hoʻihoʻi ʻana i ke kumu o 10%, 30%, 50% a me 70% o ka mahana i TR10, TR30, TR50, TR70. Lawe ka mea maʻamau i ka TR10 ma ke ʻano he kuhikuhi, e pili ana i ka mahana brittle o ka lāʻau. (2) Haʻahaʻa haʻahaʻa flexure: ma hope o ka hāpana i ka manawa i ʻōlelo ʻia i ka haʻahaʻa haʻahaʻa i ʻōlelo ʻia, ua hoʻopiʻi like ʻia e like me ka Angle i kuhikuhi ʻia, a me nā pono a me nā hemahema o ka hiki ke hoʻopaʻa ʻia o ka sila ma hope o ka hana mau ʻana o ka ikaika. ʻimi ʻia ka ukana ma ka wela haʻahaʻa. 5 ʻAila a i ʻole ke kūpaʻa maʻamau ʻO nā mea hoʻopaʻa i hoʻohui ʻia i ka hoʻopili ʻana me ka base petroleum, nā esters pālua, ka aila momona silicone, i ka ʻoihana kemika i kekahi manawa e hoʻopili pū i ka waikawa, ka alkali a me nā mea hoʻolaha kino ʻē aʻe. Ma waho aʻe o ka corrosion i loko o kēia mau media, ma ke kiʻekiʻe wela e alakaʻi i ka hoʻonui a me ka ho'ēmi ikaika, ka ho'ēmi paʻakikī; I ka manawa like, lawe ʻia ka plasticizer a me nā mea hiki ke hoʻoheheʻe ʻia i loko o ka mea hoʻopaʻa paʻa, ka hopena o ka hoʻohaʻahaʻa nui, ka hoʻohaʻahaʻa leo, ka leakage. ʻO ka mea maʻamau i kahi mahana, ma hope o ka hoʻomoʻa ʻana i ka waena no nā manawa he nui, ua hoʻoholo ʻia ka maikaʻi, ka nui, ka ikaika, ka elongation a me ka paʻakikī o ka hoʻololi ʻana e loiloi i nā pono a me nā hemahema o ke kūpaʻa aila a i ʻole ke kū kūʻē ʻana o ka mea sealing. 6 Ke kū'ē i ka wā kahiko ʻO ka mea hoʻopaʻa e ka oxygen, ka ozone, ka wela, ka māmā, ka maʻemaʻe, ka pilikia mechanical e hoʻopōʻino i ka hana, i kapa ʻia ʻo ka ʻelemakule o nā mea sealing. Hiki ke hōʻike ʻia ke kūʻē ʻana i ka wā kahiko (ʻike ʻia ʻo ka weather resistance) e ka hoʻololi ʻana o ka ikaika, elongation a me ka paʻakikī o ke ʻano ʻelemakule ma hope o ka ʻelemakule. ʻOi aku ka liʻiliʻi o ka loli, ʻoi aku ka maikaʻi o ka pale ʻana i ka wā kahiko. Nānā: ʻO ka WEATHER RESISTANCE e pili ana i nā huahana plastik ma muli o ka lā, nā loli wela, ka makani a me ka ua a me nā ʻano ʻē aʻe o waho o ka mana, a me ke ʻano o ka mae, discoloration, māwae, pauka a me ka emi ʻana o ka ikaika a me kahi ʻano o ka ʻelemakule. I waena o lākou, ʻo ka radiation ultraviolet ke kumu nui e hoʻolaha ai i ka wā kahiko. ʻO ka lua, ua hoʻokomo ʻia ka mea o ka hoʻohana pinepine ʻana i nā sila valve 1 Nitrile butadiene rubber (NBR) He copolymer irregular o butadiene a me acrylonitrile monomer synthesized e emulsion polymerization. Penei kona ʻano molekala: - (CH2-CH=CH) M - (CH2-CH2-CH) N-CN, nitrile butadiene rubber ** ua hoʻomohala ʻia ma Kelemānia i ka makahiki 1930. He copolymer o ka butadiene a 25% acrylonitrile. Ma muli o kona kūpaʻa ʻelemakule, ʻoi aku ka maikaʻi o ka pale ʻana i ka wela a me ke kūpaʻa ʻana ma mua o ka lāʻau kūlohelohe, ua uku nui ʻia e ka ʻoihana lāʻau. I ka wā o ke Kaua Honua ʻElua, me ka hoʻomohala wikiwiki ʻana o nā mea kaua a me nā mea hana, ua piʻi nui ke koi no ka wela - a me ka ʻaila-kūpaʻa nitrile rubber e like me nā mea hoʻomākaukau kaua. A hiki i kēia manawa, ʻoi aku ma mua o 20 mau ʻāina i hoʻopuka i ka NBR, me ka hoʻopuka makahiki o 560,000 tons, ʻo ia hoʻi ka 4.1% o ka nui o ka synthetic rubber o ka honua. Ma muli o kona kūpaʻa wela maikaʻi, kūʻē aila a me nā waiwai mechanical, i kēia manawa ua lilo ia i huahana nui o ka lāʻau pale ʻaila, e helu ana ma kahi o 80% o ke koi ʻana no nā ʻaila a pau. ʻO ka nitrile butadiene rubber i nā makahiki 1950 ua hana nui i ka ulu ʻana, a hiki i kēia manawa aia ma mua o 300 mau lama, e like me ka ʻike o ka acrylonitrile, ma 18% ~ 50% acrylonitrile maʻiʻo hiki ke māhele ʻia i: ʻO ka ʻike o ka acrylonitrile he 42% no ka nui loa. papa nitrile kiʻekiʻe, 36% a 41% no ka papa nitrile kiʻekiʻe, 31% a 35% no ka papa nitrile kiʻekiʻe, 25% a 30% no ka papa nitrile waena, a emi iho ma mua o 24% no ka papa nitrile haʻahaʻa. ʻO ka hoʻohana ʻana i ka ʻoihana o ka nui he nitrile haʻahaʻa haʻahaʻa -18 (hui pū ʻia me ka maʻiʻo acrylonitrile o 17% ~ 20%), ʻano nitrile grade nitrile -26 (hui pū me ka maʻiʻo acrylonitrile o 27% ~ 30%), kiʻekiʻe nitrile grade butanitrile -40 (hui pū me ka acrylonitrile maʻiʻo o 36% ~ 40%). ʻO ka hoʻonui ʻana i ka ʻike acrylonitrile hiki ke hoʻomaikaʻi maikaʻi i ka pale ʻana i ka aila a me ke kūpaʻa wela o NBR, akā ʻaʻole i ʻoi aku ka maikaʻi, no ka mea, ʻo ka hoʻonui ʻana o ka ʻike acrylonitrile e hōʻemi hoʻi i ka hana haʻahaʻa haʻahaʻa o ka rubber. Hoʻohana nui ʻia ʻo Nitrile butadiene rubber i ka hana ʻana i ka aila hydraulic ma muli o ka aila, lubricating aila, kerosene a me ka ʻaila i ka hana o nā huahana lāʻau i kona mahana hana -50-100 degere; Hiki ke hoʻohana ʻia ka hana pōkole no 150 degere, i ka ea a me ka ethanol glycerin antifreeze hana wela o -45-100 degere. ʻAʻole maikaʻi ke kūpaʻa ʻelemakule o ka nitrile, i ka wā e kiʻekiʻe ai ka ʻike o ka ozone, e wikiwiki ana ka ʻelemakule a me ka haki ʻana, ʻaʻole kūpono ia no ka hana lōʻihi i ka ea wela, ʻaʻole hiki ke hana i ka ʻaila hydraulic o ka phosphate ester. ʻO nā hiʻohiʻona kino nui o ka nitrile butadiene rubber: (1) ʻeleʻele maʻamau ka nitrile rubber, hiki ke hoʻoponopono ʻia ke kala e like me ka makemake o ka mea kūʻai aku, akā pono e hoʻonui i kekahi mau kumukūʻai, a pili paha i ka hoʻohana ʻana i ka lāʻau. (2) He ʻono liʻiliʻi ko ka nitrile rubber. (3) E like me nā hiʻohiʻona pale ʻaila o ka nitrile rubber a me ka hoʻohana ʻana i ka pae wela e hoʻoholo ai inā he nitrile rubber ka mea o ka sila. Silicone rubber (Si a i ʻole VMQ) He polymer laina ia me ka hui paʻa Si-O (-Si-O-Si) ma ke ʻano he kaulahao nui a me ka hui organik e like me ka hui ʻaoʻao. Ma muli o ka hoʻomohala ʻana o ka mokulele, aerospace a me nā ʻoihana mua ʻē aʻe, aia kahi koi wikiwiki no ke kiʻekiʻe kiʻekiʻe a me ka haʻahaʻa haʻahaʻa haʻahaʻa haʻahaʻa e hoʻopaʻa i nā mea hoʻopaʻa. ʻAʻole hiki i ka hoʻohana mua ʻana o ka mea maoli, butadiene, chloroprene a me nā mea ʻē aʻe i nā pono o ka hoʻomohala ʻana i ka ʻoihana, no laila i nā makahiki 1940 mua ma ʻAmelika Hui Pū ʻIa i hoʻomaka ai ʻelua mau hui e hoʻokomo i ka dimethyl silicone rubber, ʻo ia ka silicone rubber mua. Ua noiʻi maikaʻi ko mākou ʻāina a hoʻokomo i ka hana i nā makahiki 1960 mua. Ma hope o nā makahiki o ka hoʻomohala ʻana, ua hoʻomohala nui ʻia ke ʻano, ka hana a me ka hua o ka silica gel. ʻO nā hiʻohiʻona nui o ka silica gel: (1) pale wela silica gel kiʻekiʻe kiʻekiʻe wela kūpaʻa hana. Hiki ke hoʻohana ma 150 ℃ no ka manawa lōʻihi, ʻaʻole e loli nui ka hana; Hiki iā ia ke hana ma mua o 10,000 mau hola ma ka 200 ℃, a hiki ke hoʻohana ʻia no kahi manawa pōkole ma 350 ℃. (2) ʻO ke kūpaʻa anu ʻO ka phenyl silica gel haʻahaʻa a me ka phenyl silica gel me ka haʻahaʻa haʻahaʻa haʻahaʻa elasticity i ka wā ma luna o 0.65 ma -60 ℃ a me -70 ℃. ʻO ka mahana maʻamau o ka silica gel he -50 ℃. (3) ʻO ka pale ʻana i ka aila a me ke kūpaʻa kemika o ka silica gel i ka ethanol, ** a me nā mea hoʻoheheʻe polar ʻē aʻe a me ka ʻae ʻana i ka aila meaʻai maikaʻi loa, ke kumu wale nō ka hoʻonui liʻiliʻi, ʻaʻole e hoʻemi ʻia nā waiwai mechanical; He maikaʻi nō hoʻi ka hoʻomanawanui o ka silica gel i ka haʻahaʻa haʻahaʻa o ka waikawa, ka alkali a me ka paʻakai. Ke waiho ʻia i loko o 10% sulfuric acid solution no 7 mau lā, ʻoi aku ka liʻiliʻi o ka hoʻololi ʻana o ka leo ma mua o 1%, a ʻaʻole i hoʻololi ʻia nā waiwai mechanical. Akā ʻaʻole kūpaʻa ka silica gel i ka sulfuric acid concentrated, alkali, carbon tetrachloride a me toluene a me nā mea hoʻonā non-polar. (4) ka ikaika o ka wā kahiko, ʻo ka silica gel ka ʻike ʻana i ka ozone a ʻaʻole i hoʻohālikelike ʻia ka pale ʻana i ka radiation me ka lāʻau maʻamau. (5) Nā waiwai dielectric He kiʻekiʻe loa ka resistivity o ka silica gel (1014 ~ 1016 ω cm) a paʻa mau kona waiwai kūʻē ma kahi ākea. He kūpono no ka hoʻohana ʻana ma ke ʻano he mea insulation ma lalo o nā kūlana voltage kiʻekiʻe. (6) ʻAʻole e ʻā koke ka silica gel hana pale ahi i ke ahi, a ʻo kona hoʻopau ʻana e hoʻohua mai i ke kinoea ʻawaʻawa, a ʻo nā huahana ma hope o ka puhi ʻana e hana i ka insulating ceramic, no laila ʻo ka silica gel kahi mea maikaʻi loa e pale ai i ka lapalapa. I ka hui pū ʻana me nā hiʻohiʻona i luna, ʻo ka silica gel ka *** * hoʻohana ʻia i nā sila ʻoihana ʻenehana uila hale a i ʻole nā ​​​​ʻāpana ʻōpala, e like me ka ipu uila, ka hao, nā ʻāpana ʻōpala umu microwave; ʻO nā sila a i ʻole nā ​​ʻāpana ʻāpana i loko o ka ʻoihana uila, e like me nā kī kelepona paʻa, nā pad haʻalulu i nā DVDS, nā sila i nā hono kelepona, etc.; ʻO nā sila ma nā ʻano lako a pau e pili ana i ke kino o ke kanaka, e like me nā hue wai, nā ʻāpana wai, a me nā mea ʻē aʻe. kaulahao nui a me ke kaulahao aoao. Mai ka makahiki 1950 mai, ua hoʻomaka ʻo ʻAmelika Hui Pū ʻIa a me ka Soviet Union mua e hoʻomohala i nā elastomers fluorinated. ʻO ka mea mua i hoʻokomo ʻia ʻo ka United States DuPont a me ka hui ʻo 3M vtionA a me KEL-F ma hope o ka hapalua o ke kenekulia o ka hoʻomohala ʻana, fluorine elastomer i ka wela wela, medium resistance, haʻahaʻa haʻahaʻa haʻahaʻa a me ke kaʻina hana a me nā mea ʻē aʻe i hoʻokō i ka hoʻomohala wikiwiki, a ua hana i kahi moʻo. o nā huahana. Loaʻa i ka Fluorine glue ke kūpaʻa wela maikaʻi, ka pale ozone a me nā ʻano ʻano ʻaila hydraulic. ʻO ka mahana hana ma ka lewa he -40 ~ 250 ℃, a ʻo ka mahana hana i ka aila hydraulic -40 ~ 180 ℃. Ma muli o ka hana ʻana, hoʻopaʻa ʻana a me ka haʻahaʻa haʻahaʻa haʻahaʻa o ka lāʻau fluorine i ʻoi aku ka maikaʻi ma mua o ka lāʻau lapaʻau maʻamau, ʻoi aku ka pipiʻi o ke kumu kūʻai, no laila ua hoʻohana ʻia i loko o ka media wela kiʻekiʻe ʻaʻole kūpono ka lāʻau lapaʻau maʻamau, akā ʻaʻole no kekahi mau hopena phosphate ester. 4 EPDM (EPDM) ʻO ia ka terpolymer o ka ethylene, propylene a me kahi liʻiliʻi o nā alkenes diene i hui ʻole ʻia. I ka makahiki 1957, ua ʻike ʻo Italia i ka hana ʻenehana o ka ethylene a me ka propylene copolymer rubber (binary EPC rubber). Ma 1963, ua hoʻohui ʻo DuPONT i kahi liʻiliʻi o unconjugated circular diene e like me ke kolu o ka monomer ma ke kumu o ka binary ethylene propylene, a synthesized haʻahaʻa unsaturated ethylene propylene ternary me nā paʻa pālua ma ke kaulahao mole. Ma muli o ka hoʻopiha ʻia ʻana o ka iwi kuamoʻo, mālama ʻo EPDM i nā waiwai maikaʻi loa o ka EPDM binary i ka wā e hoʻokō ai i ke kumu o ka vulcanization. ʻO ka Epdm rubber ka maikaʻi o ka pale ʻana i ka ozone, ma ka ozone kaila o 1 * 10-6 kaiapuni ʻaʻole naʻe e haki ʻia 2430 hola; ʻO ke kūpaʻa ʻino maikaʻi: kūpaʻa maikaʻi i ka waiʻona, waikawa, alkali ikaika, oxidants, detergents, nā aila holoholona a me nā mea kanu, nā ketones, a me kekahi mau lipids (akā i ka aila ʻaila e pili ana i ka aila, ʻoi aku ka nui o ka hoʻonui ʻana i ka aila hydraulic, ʻaʻole hiki ke hana me ka ʻaila mineral. kaiapuni); ʻO ke kūpaʻa wela maikaʻi, hiki ke hoʻohana ʻia i -60 ~ 120 ℃ wela no ka manawa lōʻihi; Loaʻa iā ia ke kūpaʻa wai maikaʻi a me ka hiki ke insulation uila. Epdm rubber waihoʻoluʻu maoli he beige, maikaʻi elasticity. 5 Polyurethane elastomer He polymer ia i hana ʻia me ka polyisocyanate a me ka polyether polyol a i ʻole polyester polyol a i ʻole/a me ka mole liʻiliʻi polyol, polyamine a i ʻole ka wai a me nā mea hoʻonui kaulahao ʻē aʻe a i ʻole crosslinkers. I ka makahiki 1937, ua ʻike mua ʻo Polofesa Otto Bayer mai Kelemania e hiki ke hana ʻia ka polyurethane ma o ka hoʻohui ʻana i nā polyisocyanate a me nā polyol, a ma kēia kumu, ua komo i loko o ka noi ʻoihana. ʻO ka pae wela o ka polyurethane elastomer mai -45 ℃ a 110 ℃. Loaʻa iā ia ka elasticity kiʻekiʻe a me ka ikaika, ke kūpaʻa maikaʻi loa i ka lole, ka pale ʻana i ka aila, ke kūpaʻa luhi a me ka haʻalulu i ka nui o ka paʻakikī. ʻOi loa no ka ʻaila lubricating a me ka ʻaila ʻaila, maikaʻi ke kūpaʻa ʻana o ka pehu a ʻike ʻia ʻo ia ʻo "wear-resistant rubber". ʻO ka polyurethane elastomer he hana piha maikaʻi loa, ua hoʻohana ʻia i ka metallurgy, petroleum, automotive, mineral processing, conservancy water, textile, paʻi, lāʻau lapaʻau, haʻuki, hana meaʻai, kūkulu a me nā ʻoihana ʻoihana ʻē aʻe. 6 Polytetrafluoroethylene (PTFE) Teflon (English abbreviation Teflon a i ʻole [PTFE,F4]), ʻike ʻia ʻo "plastic king", nā inoa kālepa Pākē "Teflon", "Teflon" (Teflon), "Teflon", "Teflon ", "Teflon", "Teflon" a pēlā aku. Hana ʻia ʻo ia me ka tetrafluorethylene e ka polymerization o nā pūhui polymer, me ke kūpaʻa kemika maikaʻi loa, ka pale ʻana i ka corrosion (ʻo ia kekahi o ke kūʻē corrosion o ka honua he mau mea maikaʻi loa ia, me ka hoʻoheheʻe ʻana i ka sodium metala a me ka fluorine wai, hiki ke kū i nā mea ʻē aʻe a pau, e paila ana i ka wai. ʻAʻole hiki ke hoʻololi i ka rega, hoʻohana ʻia ʻo *** i nā ʻano pono āpau e kūʻē i ka waika a me ka alkali a me nā mea hoʻoheheʻe organik), sealing, lubrication kiʻekiʻe non-adhesive, insulation uila a me ka hoʻomanawanui anti-aging maikaʻi, ke kūpaʻa wela maikaʻi (hiki ke hana ma + 250 ℃ i -180 ℃ wela no ka manawa lōʻihi). ʻAʻole ʻawaʻawa ʻo Teflon i nā kānaka, akā ʻo ka ammonium perfluorooctanoate (PFOA), kekahi o nā mea maka i hoʻohana ʻia i ke kaʻina hana, ua manaʻo ʻia he mea make. ʻO ka mahana -20 ~ 250 ℃ (-4 ~ + 482 ° F), e ʻae ana i ka hoʻomaha ʻana a me ka hoʻomehana ʻana, a i ʻole ka hoʻololi ʻana i ka hana wela a me ke anu. ʻO ke kaomi -0.1 ~ 6.4Mpa (ʻAha piha i ka 64kgf/cm2)