Effect of Molybdate Anions On Corrosion Behavior of Stainless Steel 304 In 0.1M Nacl Solution

Abstract

The research was aimed to study the effect of molybdate ions (MoO 4 =) on corrosion behavior of SS 304 in 0.1M NaCl solution with six different concentration of molybdate ion in the range (0.01-0.3 M) at room temperature. Corrosion parameters such as open circuit potential (E ocp), corrosion potentials (E corr), corrosion current density (i corr) and Tafel slops (b c & b a)were measured and discussed. The polarization resistance (R p) and rate of the corrosion in (mpy) values were calculated, the protection efficiency (P%) in solution NaCl containing molybdate anions was also estimated. All these parameters indicated role of molybdate as inhibitor material of corrosion SS 304 in NaCl solution and exhibit that the 0.03M MoO 4-2 has the best values of R p , rate (mpy) and P%. The inhibition by molybdate was observed through adsorption process and formation of oxide layer on surface of Stainless Steel. Key Word: Corrosion of SS 304, Effect of Molybdate ions. ‫ﻋﻠﻰ‬ ‫ﺍﻟﻤﻭﻟﺒﻴﺩﺍﺕ‬ ‫ﺃﻴﻭﻨﺎﺕ‬ ‫ﺘﺄﺜﻴﺭ‬ ‫ﻟ‬ ‫ﺍﻟﺘﺄﻜﻠﻲ‬ ‫ﺍﻟﺴﻠﻭﻙ‬ ‫ﻟﻠﺼﺩﺃ‬ ‫ﺍﻟﻤﻘﺎﻭﻡ‬ ‫ﻠﺤﺩﻴﺩ‬) ٣٠٤ (‫ﻤﺤﻠﻭل‬ ‫ﻓﻲ‬ ٠.١ ‫ﺍﻟﺼﻭﺩﻴﻭﻡ‬ ‫ﻜﻠﻭﺭﻴﺩ‬ ‫ﻤﻭﻻﺭﻱ‬ ‫ﺍﻟﺨﻼﺼﺔ‬ ‫ﺍﻟ‬ ‫ﻴﺘﻀﻤﻥ‬ ‫ﺒﺤﺙ‬ ‫ﻟ‬ ‫ﻤﺤﺎﻭﻟﺔ‬ ‫ﻟﺴـﺒﻴﻜﺔ‬ ‫ﺍﻟﺘﺄﻜـل‬ ‫ﺴﻠﻭﻙ‬ ‫ﻋﻠﻰ‬ ‫ﺍﻟﻤﻭﻟﺒﻴﺩﺍﺕ‬ ‫ﺃﻴﻭﻨﺎﺕ‬ ‫ﺘﺄﺜﻴﺭ‬ ‫ﺩﺭﺍﺴﺔ‬ ٣٠٤ ‫ﻓـﻲ‬ ‫ﻤﺤﻠﻭل‬) 0.1M NaCl (‫ﺍﻟﻤﺩﻯ‬ ‫ﻀﻤﻥ‬ ‫ﺍﻟﻤﻭﻟﺒﻴﺩﺍﺕ‬ ‫ﻤﻥ‬ ‫ﺘﺭﺍﻜﻴﺯ‬ ‫ﺒﺴﺘﺔ‬) ٠.٠١-٠.٣ ‫ﻤـﻭﻻﺭﻱ‬ (‫ﺒﺩﺭﺠـﺔ‬ ‫ﺍﻟﻐﺭﻓﺔ‬ ‫ﺤﺭﺍﺭﺓ‬. ‫ﺍﻟﺘﺎﻜل‬ ‫ﺠﻬﺩ‬ ‫ﻤﺜل‬ ‫ﺍﻟﺘﺄﻜل‬ ‫ﻤﺘﻐﻴﺭﺍﺕ‬ ‫ﺒﻌﺽ‬ ‫ﻭﻤﻨﺎﻗﺸﺔ‬ ‫ﻗﻴﺎﺱ‬ ‫ﺘﻡ‬) E corr (‫ﺍﻟﺘﺎﻜـل‬ ‫ﺘﻴـﺎﺭ‬ ‫ﻭﻜﺜﺎﻓﺔ‬) i corr (‫ﻭﻤﻴﻭل‬ ‫ﻭﺍﻻﻨﻭﺩﻴﺔ‬ ‫ﺍﻟﻜﺎﺜﻭﺩﻴﺔ‬ ‫ﺘﺎﻓل‬) b c & b a .(‫ﺍﻻﺴـﺘﻘﻁﺎﺏ‬ ‫ﻤﻘﺎﻭﻤﺔ‬ ‫ﺤﺴﺎﺏ‬ ‫ﺘﻡ‬ ‫ﻜﻤﺎ‬) R p (‫ﻭﻤﻌـﺩل‬ ‫ﺒﻭﺤﺩﺓ‬ ‫ﺍﻟﺘﺎﻜل‬ ‫ﺴﺭﻋﺔ‬) ‫ﻤﻴل‬ / ‫ﺴﻨﺔ‬ (‫ﺍﻟﺼـﻭﺩﻴﻭﻡ‬ ‫ﻜﻠﻭﺭﻴـﺩ‬ ‫ﻤﺤﻠـﻭل‬ ‫ﻓﻲ‬ ‫ﺍﻟﺤﻤﺎﻴﺔ‬ ‫ﻜﻔﺎﺀﺓ‬ ‫ﺘﻘﺩﻴﺭ‬ ‫ﺍﻟﻰ‬ ‫ﺒﺎﻻﻀﺎﻓﺔ‬ ، ‫ﺍﻟﻤﻭﻟﺒﻴﺩﺍﺕ‬ ‫ﺍﻴﻭﻨﺎﺕ‬ ‫ﻋﻠﻰ‬ ‫ﺍﻟﺤﺎﻭﻱ‬. ‫ﺍﻟﻤﻘﺎﻭﻡ‬ ‫ﺍﻟﻔﻭﻻﺫ‬ ‫ﻟﺘﺄﻜل‬ ‫ﻜﻤﺜﺒﻁ‬ ‫ﺍﻟﻤﻭﻟﺒﻴﺩﺍﺕ‬ ‫ﺩﻭﺭ‬ ‫ﺒﻴﻨﺕ‬ ‫ﺍﻟﺒﻴﺎﻨﺎﺕ‬ ‫ﻫﺫﻩ‬ ‫ﻟﻠﺼـﺩﺃ‬ ٣٠٤ ‫ﺘﺭﻜﻴﺯ‬ ‫ﺍﻀﺎﻓﺔ‬ ‫ﺒﺎﻥ‬ ‫ﻭﻭﻀﺤﺕ‬ ‫ﺍﻟﺼﻭﺩﻴﻭﻡ‬ ‫ﻜﻠﻭﺭﻴﺩ‬ ‫ﻤﺤﻠﻭل‬ ‫ﻓﻲ‬ ٠.٠٣ ‫ﺍﻓﻀل‬ ‫ﺍﻋﻁﻰ‬ ‫ﺍﻟﻤﺜﺒﻁ‬ ‫ﻤﻥ‬ ‫ﻤﻭﻻﺭﻱ‬ ‫ﺍﻟﺤﻤﺎﻴﺔ‬ ‫ﻭﻜﻔﺎﺀﺓ‬ ‫ﺍﻟﻤﻘﺎﺴﺔ‬ ‫ﺍﻟﺴﺭﻋﺔ‬ ‫ﻭﻤﻌﺩل‬ ‫ﺍﻻﺴﺘﻘﻁﺎﺏ‬ ‫ﻟﻤﻘﺎﻭﻤﺔ‬ ‫ﻗﻴﻡ‬. ‫ﺨـﻼل‬ ‫ﻤﻥ‬ ‫ﹰ‬ ‫ﻭﺍﻀﺤﺎ‬ ‫ﻜﺎﻥ‬ ‫ﺍﻟﺘﺜﺒﻴﻁ‬ ‫ﺩﻭﺭ‬ ‫ﺍﻥ‬ ‫ﺍﻟﻤﻌﺩﻨﻲ‬ ‫ﺍﻟﺴﻁﺢ‬ ‫ﻋﻠﻰ‬ ‫ﺍﻟﺴﻠﺒﻴﺔ‬ ‫ﻁﺒﻘﺔ‬ ‫ﻭﺘﻜﻭﻴﻥ‬ ‫ﺍﻻﻤﺘﺯﺍﺯ‬ ‫ﻋﻤﻠﻴﺔ‬. ‫ﺘﻤـﺕ‬ ‫ﺍﻟﻘﻴﺎﺴـﺎﺕ‬ ‫ﺠﻤﻴـﻊ‬ ‫ﺍﻥ‬ ‫ﺩﺭﺠـﺔ‬ ‫ﻓـﻲ‬ ‫ﺍﻟﻐﺭﻓﺔ‬ ‫ﺤﺭﺍﺭﺓ‬ .