Corrosion Engineering MCP Server

""" NRL Physical Constants and Conversion Factors PROVENANCE: Direct 1:1 translation from MATLAB code by: Steven A. Policastro, Ph.D. Center for Corrosion Science and Engineering U.S. Naval Research Laboratory 4555 Overlook Avenue SW, Washington, DC 20375 Source: USNavalResearchLaboratory/corrosion-modeling-applications File: polarization-curve-modeling/Constants.m License: Public domain (U.S. Federal Government work) Date: 2025-10-19 """ import numpy as np class NRLConstants: """ Physical constants and conversion factors for electrochemical calculations. All values are exact transcriptions from the NRL MATLAB Constants class. """ # Fundamental Physical Constants R = 8.314 # Ideal gas constant, J/(mol·K) F = 96485.3 # Faraday constant, C/mol kb = 1.38e-23 # Boltzmann's constant, m²·kg/(s²·K) planck_h = 6.626e-34 # Planck's constant, m²·kg/s eps0 = 8.85418782e-12 # Permittivity of free space, m⁻³·kg⁻¹·s⁴·A² e = 1.6e-19 # Charge on electron, C # Reference Electrode Conversion E_SHE_to_SCE = 0.244 # Convert V_SHE to V_SCE # Unit Conversions convertCtoK = 273.15 # Celsius to Kelvin convertGtoKg = 1.0 / 1000.0 # Grams to kilograms convertKgtoMg = 1000.0 * 1000.0 # Kilograms to milligrams convertLtoCm3 = 1000 # Liters to cm³ (or mL) convertMtoCm = 100 # Meters to cm convertCm2toM2 = 1.0e-4 # cm² to m² # Solution Concentrations cH2O = 55.55 # Concentration of water, mol/L cO2 = 0.209476 # Concentration of oxygen in air, mole fraction # Molar Masses (g/mol) M_H2 = 2.016 M_OH = 17.008 M_O2 = 32.0 M_H2O = 18.01528 M_Cl = 35.5 M_NaCl = 58.4 M_Cr = 51.9961 M_Fe = 55.845 M_Ni = 58.6934 M_Cu = 63.546 # Oxide Properties MCr2O3 = 151.99 # Molar mass of Cr₂O₃, g/mol densityCr2O3 = 5.22 # Density of Cr₂O₃, g/cm³ rhoCr2O3_0 = 5000.0e9 # Resistivity of Cr₂O₃, Ω/cm iPassCr2O3 = 1.0e-6 # Passive current density for Cr₂O₃, A/cm² tCr2O3film = 2.5e-7 # Cr₂O₃ film thickness, cm # Diffusion Coefficients (cm²/s) D_H = 9.311e-5 # Diffusivity of H₃O⁺ D_H2O = 2.299e-5 # Diffusivity of H₂O D_Fe = 2.5e-12 # Diffusivity of Fe in oxide # Dielectric Constants epsH2O = 80.1 # Water epsPolyurethane = 6.19 # Polyurethane epsEpoxy = 3.6 # Epoxy # Standard Electrode Potentials (V_SHE) e0_orr_acid = 1.223 # ORR in acidic solution e0_orr_2e_alk = -0.065 # ORR 2-electron in alkaline e0_orr_alk = 0.401 # ORR in neutral/alkaline solution e0_her_alk = -0.83 # HER in neutral/alkaline solution e0_her_acid = 0.0 # HER in acidic solution e0_me_ox = 0.0 # Generic metal oxidation e0_Cr_ox = -0.74 # Cr oxidation e0_Fe_ox = -0.501 # Fe oxidation e0_Ni_ox = -0.23 # Ni oxidation e0_Cu_ox = 0.52 # Cu oxidation # Electrons Transferred z_orr = 4 # ORR: O₂ + 2H₂O + 4e⁻ → 4OH⁻ z_her = 2 # HER: 2H₂O + 2e⁻ → H₂ + 2OH⁻ z_Cr_ox = 3 # Cr → Cr³⁺ + 3e⁻ z_Fe_ox = 2 # Fe → Fe²⁺ + 2e⁻ z_Cu_ox = 1 # Cu → Cu⁺ + e⁻ z_Fe_red = 1 # Fe reduction (1 electron) z_Ni_ox = 2 # Ni → Ni²⁺ + 2e⁻ # Molar Volumes (L/mol) VO2 = 22.414 # O₂ VNaCl = 16.6 # NaCl @staticmethod def calculate_cH_and_cOH(pH: float) -> tuple[float, float]: """ Calculate H⁺ and OH⁻ concentrations from pH. Args: pH: pH value Returns: Tuple of (cH, cOH) concentrations in mol/L Example: >>> cH, cOH = NRLConstants.calculate_cH_and_cOH(7.0) >>> print(f"cH = {cH:.2e} M, cOH = {cOH:.2e} M") cH = 1.00e-07 M, cOH = 1.00e-07 M """ cH = 10.0 ** (-pH) # mol/L cOH = 10.0 ** (-(14.0 - pH)) # mol/L return cH, cOH @staticmethod def linear_linear_rational(b: np.ndarray, x: np.ndarray) -> np.ndarray: """ Linear-linear rational function. Args: b: Array of 3 parameters [b1, b2, b3] x: Domain values Returns: Range values y = (b1 + b2*x) / (1 + b3*x) Note: This function is used in the NRL MATLAB code but may not be actively used in the polarization curve calculations. """ numerator = b[0] + b[1] * x denominator = 1.0 + b[2] * x return numerator / denominator # Create module-level instance for easy access C = NRLConstants() __all__ = ['NRLConstants', 'C']