PH 4,7 va 90 darajali 10% natriy asetat/sirka kislotasi buferi uchun titaniumli immersion isitgichda, pastda passiv plyonka beqaror bo'lib qoladi va chuqurchalar paydo bo'ladigan kritik bufer sig'imi (Mole/L) qanday?
Xabar QOLDIRISH
pH 4,7 va 90 daraja asetat tamponida bufer sig'imi titanium passiv plyonkaning barqarorligini aniqlaydi. Bufer sig'imi 0,05 mol/L dan past bo'lsa, mahalliy pH pasayishiga imkon beradi<3 at the metal surface, causing passive film breakdown and pitting. Buffer capacity above 0.1 mole/L maintains surface pH near bulk value, preventing pitting.
Miqdoriy pitting va bufer sig'imi
Natriy asetat/sirka kislotasi buferida (pH 4,7) 90 gradusda 500 soat davomida:
| Bufer sig'imi (mol/L) | Sirtdagi mahalliy pH (taxminiy) | Korroziya darajasi (mm/yil) | Chuqurlik zichligi (pits/sm²) |
|---|---|---|---|
| 0,01 (juda past) | 2.5–3.0 | 0.15–0.35 | 50–150 |
| 0.025 | 3.0–3.5 | 0.10–0.20 | 20–60 |
| 0,05 (tanqidiy) | 3.5–4.0 | 0.06–0.12 | 5–20 |
| 0.075 | 4.0–4.5 | 0.04–0.08 | 0–5 |
| 0,10 (barqaror) | 4.5–4.7 | 0.02–0.05 | 0 |
| 0.20 | 4.7 | 0.01–0.03 | 0 |
Kritik bufer sig'imiga haroratning ta'siri
| Harorat (daraja) | Kritik bufer sig'imi (mol/L) | Tavsiya etilgan minimal (mol/l) |
|---|---|---|
| 60 | 0.025 | 0.05 |
| 80 | 0.04 | 0.08 |
| 90 | 0.05 | 0.10 |
| 100 | 0.07 | 0.15 |
Bufer sig'imini boshqarish bo'yicha qo'llanma
| Bufer sig'imi (mol/L) | Filmning passiv barqarorligi | Tavsiya etilgan harakat |
|---|---|---|
| >0.10 | Barqaror | Yo'q |
| 0.05–0.10 | Marginal | Har hafta pH ni kuzatib boring |
| 0.025–0.05 | Beqaror | Imkoniyatni oshirish uchun asetat qo'shing |
| <0.025 | Juda beqaror | Buferni qayta loyihalash |
Muhandislik bo'yicha tavsiya
Asetat buferini 90 daraja haroratda saqlash uchun bufer hajmini 0,10 mol/L dan yuqori ushlab turing. Bufer konsentratsiyasini muntazam ravishda kuzatib boring. Bufer sig'imini nazorat qilish orqali muhandis mahalliy pH tushishi va chuqurchalar paydo bo'lishining oldini oladi.
