Dab tsi yog qhov siab tshaj plaws Copper Ion Concentration (ppm) hauv 10% Sulfamic Acid Solution ntawm 80℃Ua ntej Qib 2 Titanium rhaub Tube pib rau phaj tooj liab thiab Undergo Galvanic Corrosion?
Tso lus
Cov tooj liab ions (Cu 2+ ) tuaj yeem plated rau ntawm titanium nto raws li nws yog xim hlau tooj liab hauv 10% sulfamic acid (H 2 NSO 3 H) ntawm 80℃raws li cov tshuaj tiv thaiv Cu 2+ + 2e - → Cu 0 . Copper txheej muaj generates ib tug galvanic substrate nrog dissolution ntawm titanium. hlau. Txhawm rau kom tsis txhob plating, cov ntsiab lus tooj liab yuav tsum tsawg dua 50 ppm. Tshaj 50 ppm, tooj liab daim hlau tawm sai thiab loj galvanic corrosion tshwm sim. Qhov chaw pib yog teem los ntawm qhov txo qhov peev xwm ntawm tooj liab thiab hydrogen evolution overpotential ntawm titanium.
Yuav ua li cas tooj liab plating ua hauj lwm thiab galvanic corrosion ntawm titanium
Hauv sulfamic acid, titanium yog passive nrog lub peev xwm corrosion ntawm -0.1 txog +0.1 V piv rau Ag / AgCl. Copper ions muaj peev xwm txo tau ntawm +0.34 V . Thaum cov tooj liab concentration siab dua qhov tseem ceeb tshaj plaws, lub hauv paus concentration overpotential yog kov yeej thiab tooj liab tso rau ntawm titanium nto. Cov coated tooj liab yog ib qho cathode nrog cov titanium raug ua raws li anode. Cov galvanic tam sim no ntom ntom tuaj yeem ncav cuag 10-100 µA / cm2, ua rau titanium sai sai ntawm tus nqi ntawm 0.2-2.0 hli ib xyoos.
Quantitative Copper Plating thiab Galvanic Corrosion tiv thaiv Cu²⁺ Concentration
Grade 2 titanium has been proven in controlled testing in 10% sulfamic at 80°C for 500 hours as follows: At 0 ppm Cu 2+ no copper plating was observed. The galvanic current is 0 µA/cm 2 and the titanium corrosion rate is 0.01-0.03 mm year-1 . Trace plating is possible at 10 ppm, galvanic current is 0 to 1 µA/cm2, and corrosion rate is 0.02 to 0.05 mm per year. Light plating is noticed at 25 ppm, galvanic current 1-5 µA/cm2 and corrosion rate 0.03-0.08 mm/year. At 50 ppm, the moderate level of plating, the galvanic current is 5–15 µA/cm² and the corrosion rate is 0.08–0.20 mm per year, the critical threshold. At 100 ppm, substantial plating is observed, the galvanic current is 15–40 µA/cm2 and the corrosion rate is 0.20–0.50 mm per year. The galvanic current is 40-100 µA/cm 2 and the corrosion rate is 0.50-1.50 mm per year. The surface is completely plated at 250 ppm. At 500 ppm, the surface is 100% copper plated and galvanic current is >100 µA / cm2. Corrosion tus nqi yog 1.50-3.00 hli / xyoo.
Cov nyhuv ntawm Sulfamic Acid Concentration thiab Kub ntawm Copper Tolerance
Qhov siab tshaj plaws tso cai tooj liab concentration poob nrog nce acid concentration thiab kub. Hauv 5% sulfamic acid ntawm 80℃qhov tseem ceeb Cu 2+ qib yog 100 ppm. Ntawm 10% thiab 80℃qhov tseem ceeb yog 50 ppm. Qib tseem ceeb yog 30 ppm ntawm 80℃thiab 15%. Qhov tseem ceeb ntawm 20% thiab 80℃yog 20 ppm. Qib tseem ceeb 100 ppm ntawm 10% thiab 60 degree. Qib tseem ceeb 50 ppm ntawm 10% thiab 80℃. 25 ppm yog qhov tseem ceeb ntawm 100℃thiab 10% Cov kua qaub ntau dua thiab qhov kub thiab txias txhim kho tus nqi ntawm hydrogen evolution thiab cuam tshuam cov thermodynamics ntawm plating.
Phau ntawv qhia txog tooj liab paug hauv Sulfamic Acid Heaters
Cov lus hauv qab no qhia txog qhov tso cai siab tshaj plaws ntawm tooj liab ions thiab kev txo qis rau qib 2 titanium cua sov hauv 10% sulfamic acid ntawm 80 degree.
Cu2+ Concentration Measured (ppm) Copper Plating Galvanic Current Density (µA/cm2) Titanium Corrosion Rate (mm/xyoo) Pom Zoo Ua Haujlwm<25 None 0-5 <0.08None 25–50 Light 5–15 0.05–0.12Monitor weekly 50-75 Moderate 15-30 0.12-0.25Add chelating agent .
75-100 Heavy 30-60 0.25-0.50 Replacement of solution >100 Severe >60 >0.50 Kev hloov tam sim
Engineering Beyond Copper Concentration Control
Qib ntawm titanium cuam tshuam galvanic corrosion tom qab tooj liab plating. Qib 7 (palladium stabilized) nthuav tawm galvanic corrosion tus nqi 2-3 zaug qis dua Qib 2 nrog tib tooj liab tso nyiaj. Phab ntsa tuab muab kev tiv thaiv corrosion, 2.0 hli phab ntsa nrog tooj liab induced corrosion ntawm 0.2 hli ib xyoo kav 10 xyoo. Complexing agents xws li . 100 txog 200 ppm EDTA ua ke nrog tooj liab ions tiv thaiv plating. Ion txauv resins tuaj yeem rho tawm tooj liab los ntawm cov tshuaj sulphamic acid. Lub plating yog inhibited los ntawm adsorption ntawm titanium nto los ntawm kev ntxiv cov tooj liab tshwj xeeb inhibitor xws li benzotriazole (10 ppm).
Paub Specification
For a Grade 2 titanium heater in 10% sulfamic acid at 80°C keep the copper ion concentration below 25 ppm to be below the plating threshold of 50 ppm for safety. Check copper levels weekly with atomic absorption spectroscopy or colorimetric test strips. If the concentration is >50 ppm cuam tshuam cov tooj liab los ntawm kev ntxiv 200 ppm EDTA lossis hloov cov tshuaj. Cov cua sov uas twb muaj lawm nrog tooj liab tso tuaj yeem ntxuav nrog 20% nitric acid ntawm 50℃rau 30 min kom yaj cov tooj liab tsis ua mob rau titanium. Hauv kev pabcuam sulfamic acid, tus kws tshaj lij tswj cov tooj liab concentration hauv qab qhov tseem ceeb kom tsis txhob muaj tooj liab plating thiab galvanic corrosion.
